The Effects of Different Tillages on Crop Residue Sequestration

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河西灌区麦茬免耕对春玉米田土壤微生物量氮和磷的影响

河西灌区麦茬免耕对春玉米田土壤微生物量氮和磷的影响张文颖,张恩和,张凤云(甘肃农业大学农学院,甘肃兰州　730070) 摘要:2004～2005年,在甘肃河西走廊的黑河灌区,设计20cm 留茬压倒(N PS20)、40cm 留茬压倒(NPS40)、40cm 立秆(NS40)、20c m 立秆(NS20)和传统耕作(CT )5个耕作处理,I 1(5400m 3/hm 2)和I 2(3600m 3/hm 2)2个灌溉水平,研究了春小麦不同留茬高度、不同留茬方式对春玉米田在不同灌水水平下土壤微生物量N 和P 的季节性变化的影响.结果表明:土壤微生物量N 春种前有表聚的现象,土壤微生物量P 则在整个耕层分布比较均匀;留茬免耕可显著增加播种前0～5c m 土层土壤微生物量N 和P 含量,10～20c m 土层则变化较小;连续免耕2a 后,春种前0～5c m 土层土壤微生物量N 和P 的增殖,分别以20cm 留茬压倒免耕处理(NPS 20)和40c m 留茬压倒免耕处理(NP S 40)的最高,分别增加了23.97%和148.80%,且土壤水分对表土层及耕层的土壤微生物量P 的影响较土壤微生物量N 显著. 关键词:绿洲灌区;春玉米;留茬免耕;土壤微生物量氮;土壤微生物量磷中图分类号:S 154.3 文献标识码:A 文章编号:100324315(2006)0620108206Effects of no 2tillage with stubble on soil microbial bio massN and P in irrigated oasis of t he Hexi CorridorZHAN G Wen 2ying ,ZHAN G En 2he ,ZHAN G Feng 2yun(Colle ge of Agronomy ,G ansu Agricultural Univer sity ,La nzhou 730070,China) Abstract :During 2004to 2005,a field experi ment wa s carried out to st udy t he effect s of different sp ri ng wheat st ubble st ayi ng t reat ment s (N PS 20、N PS 40、NS 40、NS 20、C T )a nd 2i rri gation l evel (5400m 3/hm 2and 3600m 3/hm 2)in no 2t illage wit h st ubbl e on soil microbi al biomass N and P.The result s showed t hat soil microbial biomass N (SMB 2N )wa s collected i n soil surface layer before seedli ng ti me whil e soil microbial biomass P (SMB 2P)wa s average d.Conservation t illage increased SMB -N a nd SMB 2P in 0～5cm soil layer ,while t hat i n 10～20cm soil l ayer had no significant difference duri ng sowi ng sta 2pare d wit h t he resul t of t he last year ,t he hi ghest increased quantit y of SMB 2N and SMB 2P i n 0～5cm soil layer appeared i n N PS 20and N PS 40respectively ,w hi ch reached to 23.97%and 148.80%,and soil water had more evi dent effect on SMB 2P t han on SMB 2N. K ey w or ds :oasis i rrigat ed a rea ;no 2t illage wit h st ubbl e ;spring maize ;soil micro bial bioma ss nit rogen ;soil microbial bioma ss phosphor us作者简介:张文颖(1980-),女,甘肃民勤人,在读硕士,主要从事保护性耕作土壤生态效应方面的研究.资助基金:国家高科技研究发展计划(863计划)资助项目(2002AA2Z4191).通讯作者:张恩和(1966-),男,教授,博士生导师,主要从事农作制度和特用作物方面的研究.E -mail :zhangeh @ 收稿日期62006年12月第6期108～113甘　肃　农　业　大　学　学　报JOURNAL O F G ANSU A GRICUL TURAL UNIVERSIT Y 第41卷双月刊:200-02-27 河西走廊是西北地区的主要商品粮基地,长期以来由于片面追求高产量,盲目地开采各种资源,使得该区的生态环境每况愈下.大量研究证明[1],秸秆还田可培肥土壤,提高土壤质量,特别是能改善土壤结构,调节土壤水、肥、气、热和生物活性以及稳定、持续地供给作物养分.高留茬免耕保护性耕作在河西走廊这一特殊的绿洲气候条件下已逐渐开始试验推广,作为一项切实有效的耕作方式,它可防止风蚀、保持水土、增加土壤肥力.土壤微生物是土壤中物质分解、转化和养分循环的主动力,土壤微生物量及其周转对植物有效养分起着储备库和源的作用,对土壤碳、氮、磷和硫的植物有效性及其在陆地生态系统的信号发生深刻的影响[2].作为土壤肥力的活指标[3],其本身也是土壤氮素转化的活性库之一[4].耕作土壤由于大量农作物被移出农田,造成微生物的能源缺乏,而在秸秆还田免耕下施用有机肥则可使土壤表层的微生物量明显增加.土壤氮素主要集中在耕层,且93%～97%以有机氮的形式存在,土壤微生物是植物有效氮的重要储备,施用无机氮时添加C/N比较高的秸秆,可以减少无机氮的淋失或挥发散失,提高氮肥的利用率.土壤微生物磷通常占全磷的2.4%～23.3%,微生物磷是有机磷中活性较高的部分,它不仅是土壤有效磷的重要来源,而且与土壤有效磷直接相平衡[5].因此,在河西走廊开展免耕条件下土壤微生物量的研究,对于提高该区的土壤自然肥力、保护生态环境和推广保护性耕作具有重要的理论指导意义.1　试验设计与方法1.1　试验区概况试验区位于河西走廊凹陷带张掖盆地的黑河灌区,地理坐标E100°10′～100°35′,N38°50′～39°09′之间,海拔1440～1600m.该区属大陆性干旱气候,冬夏较长,春秋较短,春季多风少雨,冬季较为寒冷.多年平均气温7.0℃,最低气温-28℃,最高气温38.5℃,≥10℃的活动积温3234.3℃;年平均降水量125mm,蒸发量2291mm,年日照时数8～33,平均冻土深度,无霜期8具有日照时间长、太阳辐射强、昼夜温差大、降水稀少、蒸发强烈、光热资源丰富等特点,适宜多种农作物生长.试验地土壤为灌漠土,耕层(0～20cm)土壤理化性状为:有机质17.98g/kg,全氮0.77 g/kg,碱解氮49.2mg/kg,全磷0.1413%,速效磷9.11mg/kg,速效钾93.95mg/kg,阳离子代换量为8.02me/100g土,p H值为8.83.1.2　试验设计试验于2004年春小麦收割后布置留茬,分20 cm和40cm2种留茬高度,立秆留茬和留茬收后压倒2种留茬方式,连续进行2a留茬免耕.试验设NS20(20cm留茬立秆免耕)、NS40(40cm留茬立秆免耕)、N PS20(20cm留茬压倒免耕)、NP S40(40cm 留茬压倒免耕)、C T(传统耕作)5个主处理,灌水量I1(5400m3/hm2)和I2(3600m3/hm2)2个副处理,供试玉米品种为中单2号,采用裂区设计,共10个处理(表1),每处理重复3次.小区面积11.5m×8 m,在各小区之间间隔留0.5m和1.0m的走道,防止水分侧渗,并供行人和灌溉,栽培管理同大田.春玉米试验过程中不施农家肥,基肥(纯N213.3 kg/hm2,纯P2O590kg/hm2)于播种前用免耕播种机施入,追肥于拔节期和灌浆期进行.冬季灌溉定额各处理均为1200m3/hm2,玉米生育期分3次进行灌水,灌水定额分别为拔节期900m3/hm2、1500 m3/hm2;抽穗期900m3/hm2、1500m3/hm2;灌浆期600m3/hm2、1200m3/hm2.表1　试验设计Ta b.1　Experimental design试验处理试验因素灌溉定额/m3hm-2留茬高度/cm覆盖方式耕作措施S20I1570020立秆免耕NS20I2390020NP S20I1570020收后压倒免耕NP S20I2390020NS40I1570040立秆免耕NS40I2390040NP S40I1570040收后压倒免耕NP S40I2390040C TI15700不留茬铁茬传统耕作C TI23900不留茬　注:灌水处理是在覆盖、耕作措施的基础上进行裂区设计的,故休闲期和播种前土壤微生物量的测定不涉及灌水量的影响3　取样及测定方法于春小麦播种前(3年月)、春小麦收获后901第6期张文颖等:河西灌区麦茬免耕对春玉米田土壤微生物量氮和磷的影响 20000h120cm14 d.. 1.2004(2004年7月)、春小麦留茬休闲期(2004年10月)、春玉米播种前(2005年4月)和春玉米收获后(2005年10月)分3次取样.取样时采用口径6.5cm 的土钻,在各小区以蛇形取样法在0～5c m ,5～10cm ,10～20cm 土层随机选取5点,分层取样后将各层次的样制成混合样放在保鲜袋中保存,并尽快带回试验室冷藏备用.测定时,先将土壤过2mm 筛,捡去可见有机物.土壤微生物N 采用氯仿熏蒸,0.5mol/L K 2SO 4浸提法(土∶水=1∶2)测定[6];土壤微生物P 采用氯仿熏蒸,0.5mol/L Na HCO 3浸提法(土∶水=1∶4)测定[7,8].2　结果与分析2.1　麦茬免耕对土壤微生物量N 的影响测试表明(表2),春小麦收获后留茬覆盖对土壤微生物量N 的影响,在各时期有相同的结果.同一留茬量下,0～5cm 土层土壤微生物量N 均是留茬压倒处理高于立秆留茬处理,且0～5cm 土层和耕层的土壤微生物量N 以留茬量较大的处理N PS 40最高.播前和休闲期分别较对照增加261.49%和121.00%.这主要是由于:收获期,气温很高而土壤含水量很低,与立秆相比免耕的压倒处理能更好地保持表层的土壤含水量,不致使水分含量在高温季节降到很低,较大的覆盖量且将秸秆压倒为此期土壤微生物提供了较为适宜的增殖环境;而立秆处理则由于较低的表层土壤含水量,影响了微生物态养分的转化.传统耕作与免耕处理相比则由于地表完全裸露,造成微生物的能源缺乏,从而严重制约了表层微生物的增殖,使之处于最低水平.休闲期,土壤都未经扰动,但免耕处理均有留茬覆盖地表,减少了土壤水分蒸发,使土壤微生物活动具有较为丰富的碳源和土壤水分,为土壤微生物提供了适宜的增殖环境.对传统耕作而言,裸露的地表、极低的表层土壤含水量都不利于微生物的活动,从而影响了0～5cm 土层微生物体内养分的转化,而5～10cm 和10～20cm 土层则由于前茬作物大量根系和根系分泌物的存在缓解了不利因素的影响. 耕作方式对土壤微生物量及其分布影响较大(表2),休闲期土壤微生物量N 含量,免耕处理均高于传统耕作,免耕处理各层次之间的差异较大,且表层含量相对较高,而传统耕作则各层次较为接近.0～5cm 土层的土壤微生物量N 含量以留茬40cm 压倒处理的最高;5～10cm 土层则是处理N PS 20的最高,且与N S 40、NS 20差异显著(P <0.05);10～20cm 土层各处理间差异不明显.在相同覆盖量下,20cm 留茬处理的0～5cm 和5～10cm 土层的土壤微生物量N 含量均是压倒处理高于立秆处理;10～20cm 土层则是立杆留茬处理高于留茬压倒处理,但各层次之间差异不显著;40cm 留茬处理的土壤微生物量N 含量在各土层均为留茬压倒处理高于立秆留茬处理,且各层次之间差异显著.表2　麦茬免耕对土壤微生物量N 含量的影响Ta b.2　E ff ect s of no 2tillage with stubble cover on soil microbial bio ma ss N测定时间/年2月层次/cm不同处理下土壤微生物量N 含量/mg kg -1NS 20NS 40NPS 20NP S 40C T 2004204(播种期)0～529.07a bA 38.39abA 29.87abA 42.33aA 11.71bA 5～108.71a A 18.64aA 18.63aA 16.03aA 9.74aA 10～2014.78bA 14.17bA 35.77aA 18.34a bA 10.43bA 2004207(收获期)0～57.55bA 20.82abA 27.70aA 22.26a bA 22.55a bA 5～1021.09a A 21.01aA 13.48abA 16.81aA 10.86bA 10～2020.48a A 9.51aA 16.69aA 8.92aA 14.77aA 2004210(休闲期)0～518.07a bA 29.66aA 26.14aA 37.88aA 17.14bA 5～1010.36bA 11.83bA 22.32aA 14.66aA 18.40aA 10～2026.17a A 13.86abA 19.76aA 19.03aA 11.14bA 2005204(播种期)0～535.86a A 43.57aA 37.03aA 46.40aA 15.02bB 5～5a bA abA 3aA 38aA 3bA ～365B65 注灌水处理是在覆盖、耕作措施的基础上进行裂区设计的,故休闲期和播种前土壤微生物量的测定不涉及灌水量的影响011 甘肃农业大学学报 2006年101.9420.722.4424.1.0710201.7a bA1.22a 20.4aA22.19aA10.0bA:. 春种前,除2004年4月在处理NS20的5～10 cm土层,其他免耕处理各层次土壤微生物量N含量均高于传统耕作,且0～5cm土层的土壤微生物量N含量相对处于最高水平,与其他层次间差异显著(P<0.05),说明此期的微生物量N有表聚的现象.免耕处理的土壤微生物量N含量与传统耕作在0～5c m土层差异显著;5～10cm土层免耕1a后与传统耕作无明显差异,免耕2a后留茬收后压倒处理较传统耕作显著增加;10～20cm土层免耕2a 后,留茬压倒处理高于立秆留茬处理和传统耕作.不同留茬方式之间,除40cm留茬处理的5～10cm土层和20cm留茬处理的0～5cm土层外,压倒处理土壤微生物量N含量均高于立茬处理,且留茬越高,表层土壤微生物量N含量越高,这与影响土壤微生物量C在同一时期变化的低温有关.相对于免耕处理,传统耕作由于春耕使残留于地表的作物秸秆和根系均匀分布于耕层中,致使该时期传统耕作各层次之间微生物量N含量无显著差异.表3　麦茬免耕对不同灌水量下春玉米收获后土壤微生物量N含量的影响Tab.3　Effect s of n o2tillage with stubble cover on s oil mic robial biomass N under diffe rent ir rigation water qua ntitymg/kg层次/cm不同处理下土壤微生物量N含量NS20I1NS20I2NS40I1NS40I2NPS20I1NS20I2NPS40I1NP S40I2C TI1C TI20～550.38aA 6.61b B18.36bA16.96a A32.19a A13.24bB21.91aA45.29aA 3.44bB17.26aA 5～109.44b B 5.98b B18.98bA15.94a A43.50a A47.03aA13.51aA11.34bB10.63bB9.74aA 10～2023.77b B36.97aA35.51aA26.06a A38.22a A44.27aA18.43aA14.37bB41.47aA14.38aA 收获期,耕层土壤微生物量N含量处理NPS40与传统耕作接近,其他免耕处理均高于传统耕作,且处理N PS20的增幅最大(20.11%),但仍与传统耕作差异不显著.处理N PS20、N PS40、NS40和传统耕作的耕层土壤微生物量N含量最高值都出现在0～5 cm土层,而处理NS20的0～5cm土层土壤微生物量N含量在耕层处于最低水平,这可能是由于处理N S20具有较高的产量造成的.5～10cm土层的土壤微生物量N含量在此期表现为立秆留茬处理相对于留茬压倒处理和传统耕作均有所增加,且与传统耕作之间差异显著,这与播种期有所不同;10～20 cm土层各处理之间均无显著性差异.2005年10月的测定结果表明(表3),在相同的留茬量和灌水量下,0～5cm土层的土壤微生物量N含量高留茬量下压倒处理高于立秆处理;低留茬量下无规律可寻. 5～10cm土层,低留茬量下,压倒处理高于立秆处理;高留茬量下,立秆处理则相对较高;10～20cm 土层与5～10cm土层也具有相同的趋势.在同一灌水量下,高灌量的立秆留茬处理在0～5cm土层的土壤微生物量N含量,20cm留茬处理高于40cm 留茬处理,留茬压倒处理则相反;低灌量下,留茬量大的处理其微生物量N含量高于留茬量较小的处理,说明在土壤水分成为微生物活动主要制约因子的收获期,高留茬可更好地保持土壤表层水分,利于微生物的快速增殖. 年际比较表明(表2),春种前免耕处理的0～5 cm土层土壤微生物量N含量均有所增加,且留茬20cm处理的增幅较大,分别为30.24%和23.98%;5～10cm土层与此有相同的趋势;10～20cm土层则变化较小.耕层平均土壤微生物量N 含量,留茬20cm处理的变化不明显,留茬40cm处理的则表现为增加,且与传统耕作差异显著.传统耕作在各时期变化均较小,且各层次间较为接近,说明高留茬免耕处理可显著增加播种期的土壤微生物量N含量.2.2　麦茬免耕对土壤微生物量P含量的影响由表4可知,土壤微生物量P含量在各时期的变化不如微生物量N的明显.免耕1a后的收获期与春种前相比,除处理NS40外,0～5cm土层的土壤微生物量P含量均是收获期高于春种前,耕层含量则是春种前高于收获期,说明春种前土壤微生物量P有向整个耕层平均的趋势,而收获期则有表聚的现象. 春种前(2004年4月),各处理间耕层土壤微生物量P含量在各层次之间均无显著性差异.经过2a 免耕后(5年月),各处理～5土层土壤微生物量含量无显著性差异;5～土层,处理NS的含量最高,且立秆留茬处理高于留茬压倒处111第6期张文颖等:河西灌区麦茬免耕对春玉米田土壤微生物量氮和磷的影响 20040cmP10cm40理;10～20cm 土层,免耕处理均高于传统耕作,免耕处理间在同一留茬量下差异不显著.说明高留茬量下,土壤温度是微生物量P 含量的主要影响因素;低留茬量下,土壤水分又成为主要制约因素. 收获期,不同耕作方式之间土壤微生物量P 含量,0～5cm 土层和5～10cm 土层均是传统耕作高于免耕处理,尤其以5～10cm 土层差异较大,传统耕作显著高于处理N S 40(P <0.05).10～20cm 土层不同耕作方式之间无明显差异.免耕处理0～5cm 土层的土壤微生物量P 含量均为压倒处理显著高于立秆留茬处理;5～10cm 土层则有相反的趋势;10～20cm 土层各处理间差异较小.此期传统耕作表层土壤微生物量P 含量高于免耕处理的原因,可能是免耕处理的产量相对较高,从而消耗了较多的矿化态P ,造成土壤微生物和作物之间对养分吸收的激烈竞争,影响了微生物的增殖. 休闲期,不同耕作方式之间土壤微生物量P 含量,0～5cm 土层处理N S 20的最高,处理NS 40的最低,且二者差异显著(P <0.05);5～10cm 土层处理NS 20的仍最高,N PS 40的最低,前者比后者增加了213.57%;10～20cm 土层传统耕作相对处于较高水平,说明在气温较高而降水较为丰富的休闲期,留茬20cm 有助于土壤微生物态P 的转化.在同一留茬量下,0～5cm 土层的土壤微生物量P 含量,低留茬量下立秆处理高于留茬压倒处理,高留茬量下则相反;5～10cm 土层均为立秆留茬较高;10～20cm 土层则是压倒处理占优势,这可能与土壤通气状况和水分含量有关.表4　麦茬免耕对土壤微生物量P 含量的影响Tab.4　Effect s of n o 2tillage wit h stubble cover on s oil mic robial biomass Pmg/kg测定时间/年2月层次/cm不同处理下土壤微生物量P 含量/mgkg -1NS 20NS 40NPS 20NP S 40C T 0～51.30aA4.59aA2.10aA1.66aA1.71aA 2004204(春种前)5～10 1.40aA2.38aA 1.80aA 1.74aA 0.65aA 10～200.97aA 2.32aA 1.05aA 1.02aA 1.00aA 0～52.41abAB 0.55bB 4.27aAB3.59aAB 5.34aA 2004207(收获后)5～10 1.91abA 1.37bA 1.42bA 0.52bA4.87aA 10～200.50aA 0.71aA 1.72aA 0.18aA 0.68aA 0～58.31aA 2.08bA 3.58aA 5.05aA 3.40a bA 2004210(休闲期)5～10 4.39aA 1.95abA 3.57aA 1.40bA 3.17aA 10～200.54aA 0.28aA 1.56aA 0.94aA 1.02aA 0～53.11aA 3.67aA 3.43aA4.13aA 2.13aA 2005204(春种前)5～10 1.91aA 3.04aA 1.76abA 0.20bB 0.91bB 10～200.27bA0.91aA0.58abA0.67aA1.14aA 随着免耕年限的延长(2005年4月),免耕处理的土壤微生物量P 含量较传统耕作均有所增加,处理NPS 40的增幅最大(93.90%),其次为NS 40、N PS 20和NS 20,分别较传统耕作增加了72.30%、61.03%、46.01%.与2004年4月相比,除处理N S 40外,其他免耕处理0～5cm 土层的土壤微生物量P 含量均有所增加,处理N PS 40的增殖最高,达148.80%.5～10cm 土层立秆留茬处理表现为增加,留茬压倒处理却有所下降,10～20cm 土层各留茬处理较上年均表现为减少.传统耕作不同年份间微生物量P 变化较为平缓.说明留茬免耕对春种前土壤微生物量P 的增殖作用主要表现在表层.表5　麦茬免耕对不同灌水量下春玉米收获后土壤微生物量P 含量的影响Ta b.5　E ff ects of no 2tilla ge with stubble cove r on soil microbial biomass P unde r diff erent ir rigation water qua ntitymg/kg层次/cm 不同处理下土壤微生物量N 含量NS 20I 1NS 20I 2NS 40I 1NS 40I 2NPS 20I 1NS 20I 2NPS 40I 1NP S 40I 2C TI 1C TI 2～553356636835～5568538365586～55B85B638B33211 甘肃农业大学学报 2006年0 1.9aA1.4aA.71aA1.27aA.21aA0.7a A4.4a A.0aA1.0aA1.2aA 102.2aA 2.aA 2.aA 1.aA .aA 2.19a A 2.0a A 2.2aA 1.4aA 0.41aA 10201.19aA4.1aA0.2b 0.7aA0.7b 1.a A0.4b 1.4aA0.0aA1.44aA 春玉米收获期(表5),除NP S20I2外,其他免耕处理0～5cm土层的土壤微生物量P含量均高于传统耕作,整个耕层也存在着相同的趋势.处理NPS20 I1在0～5cm土层的土壤微生物量P含量最高,且与相同灌水量下对照的差异达到显著性水平.免耕处理之间的比较表明,在相同留茬量下,高灌量处理的土壤微生物量P含量高于低灌量处理,且各层次间差异显著,表层含量高于下层.在灌水量相同而留茬方式不同时,高灌量下压倒处理的土壤微生物量P含量高于立秆留茬处理;低灌量下,2种留茬方式下变化趋势相反,这与土壤微生物量C和N的变化趋势有所不同,说明土壤水分对表土层及耕层土壤微生物量P的影响较C和N显著.3　小结与讨论 1)　留茬免耕由于土壤表层留有大量的作物秸秆、根茬,使得0～5cm土层的土壤微生物学性质发生了深刻的变化.留茬免耕1a后,与传统耕作相比,春种前微生物量N含量明显增加,收获期变化不大;微生物量P含量在播种期免耕处理相对于传统耕作明显地增加,收获期反而低于传统耕作;免耕2a后,土壤微生物量N含量在春种前较上年有增加的趋势.说明土壤微生物量的季节性变化主要与能源的供应有关. 2)　留茬免耕处理后,0～5cm土层土壤微生物量N含量在各时期表现为:压倒处理高于立秆处理,且0～5cm土层土壤微生物量N含量以高留茬量下的处理NPS40为最高,说明免耕与留茬覆盖相结合,且留茬采用压倒的方式可增加耕层的土壤微生物量N,以便更好地改善土壤肥力状况,这与陈蓓等[9]的研究结果相似. 3)　土壤水分和温度是影响微生物量变化的主要因素,留茬免耕处理后土壤微生物量N在春种前有表聚的现象,土壤微生物量P则有向整个耕层平均的趋势. 4)　土壤水分对土壤微生物的增殖产生深刻的影响,收获期微生物量N含量相对处于最低水平,高留茬则有利于缓解水分对收获期微生物增殖的限制,这与高云超等[10].的结果相似土壤微生物量P 的季节性变化不明显,但土壤水分对表土层及耕层的土壤微生物量P的影响较N显著.参考文献[1]　张成娥,王栓全.作物秸秆腐解过程中土壤微生物量的研究[J].水土保持学报,2000,14(3):96～99[2]　Smit h J L,Paul E A.The significa nce of soil microbialbioma ss e stimation in soil bioche mist ry[M].Bollag,JM G Stozzy:New Y ork,Marcel de kker,Inc,1991,359～396[3]　Shaver T M,Peter son G A.Surface soil physical prop2ertie s af ter twelve year s of dryland no2tilled manage2 ment[J].Soil Science Society of Ame rica Journal, 2002,66:1296～1303[4]　田育军,林　杉,赵笃乐,等.长期不同施肥土壤微生物态氮作为土壤供氮指标的研究[J].甘肃农业大学学报,2000,35(1):24～28[5]　何振立.土壤微生物量及其在养分循环和环境质量评价中的意义[J].土壤,1997,(2):61～69[6]　Brooke s P C,La ndma n A,Pruden G,e t al.Chlorofor mf umigation and t he relea se of soil nitroge n:a rapid di2rect extraction method to mea sure microbial biomass nit rogen in soil.Soil Biol Bioc hem,1985,17:837～842 [7]　Brookes P C,Powlson D S,Je nkinson D S.Measure2ment of microbial biomass phosp horus in t he soil.SoilBiol Bioche m,1982,(14):319～329[8]　McL aughlin M J,Al ston A M.Mea surement of phos2p horus in the soil mic robial biomass:a modified p roce2 dure for field soil s.Soil Biol Bioche m,1986,18:437～443[9]　陈　蓓,张仁陟.免耕与覆盖对土壤微生物数量及组成的影响[J].甘肃农业大学学报,2004,39(6):634～638 [10]　高云超,朱文珊,陈文新.秸秆覆盖免耕土壤微生物量与养分转化的研究[J].中国农业科学,1994,27(6):41～49[11]　姜小凤,张仁陟,王玲英,等.不同耕作方式对旱地土壤酸解有机总氮的影响[J].甘肃农业大学学报,2006,41(1):48～51311第6期张文颖等:河西灌区麦茬免耕对春玉米田土壤微生物量氮和磷的影响。

Soil Erosion

Rainsplash
Rain may move soil directly: 'rainsplash erosion'. The rain must fall with sufficient intensity on bare soil to detach and move soil particles a short distance. This is solely an on-site effect.
Soil may be detached and moved by water, wind or tillage. These three processes, however, differ greatly in terms of:
•where and when they occur
•what happens to the area that is being eroded
thinking of the exhaustion of our natural resources, and especially of soil erosion and these are perhaps more dangerous still,
because once we begin to feel their repercussions it will be too late." (p144 of The Dalai Lama's Little Book of Inner Peace:
How could something so ‘natural’ be so bad? Soil erosion is natural after all. However, when we change the

不同机械化整地技术对稻田土壤理化性质和水稻产量的影响

不同机械化整地技术对稻田土壤理化性质和水稻产量的影响作者：***来源：《安徽农业科学》2021年第14期摘要 [目的]了解不同机械化整地技术对稻田土壤理化性状和水稻产量的影响，为机械化技术模式的推广和开发新型农业机械提供参考。

[方法]2017—2019年在安徽省肥东县进行田间试验，比较3种不同机械化整地方式旋耕（处理①）、深松（处理②）、深翻（处理③）对稻田0～10、10～20、20～30 cm土层土壤理化性质和水稻产量的影响。

[结果]与处理①相比，处理②和③在0～20 cm土层可导致土壤含水率降低9.67%～26.79%，土壤容重增加0.08～0.16g/cm3，且差异达到显著水平，土壤透气性有所提高，土壤孔隙度降低3.05%～11.67%;各土层总体表现出有机碳、全氮和碱解氮含量均逐渐降低，0～10 cm土层的有机质、全氮和碱解氮含量均低于处理①;处理②条件下水稻产量2年持续增加，第1、2年分别增产4.91%和9.54%，处理③对水稻产量影响较小，仅在第2年呈现出增长的趋势，但是差异不显著。

[结论]深松可以提高稻田土壤向下的透水性和容重，对土壤有机质和氮素影响较小，可连年增加水稻产量。

深翻虽然也可以改善土壤的理化性质，但是效果较深松处理差，且会降低上层土壤肥力，水稻产量增加不明显。

关键词机械化;整地技术;水稻;土壤;理化性质;产量中图分类号 S 28 文献标识码 A 文章编号 0517-6611（2021）14-0200-03Abstract [Objective] To understand the effects of different mechanized soil preparation technologies on the physical and chemical properties of paddy soil and rice yield， and to provide references for the promotion of mechanized technology models and the development of new agricultural machinery.[Method]Field trials were carried out in Feidong County， Anhui Province from 2017 to 2019. Three different mechanized land preparation methods were compared with rotary tillage （treatment ①）， subsoiling （treatment ②） and deep plowing （treatment ③） on rice fields of 0-10，10-20，20-30 cm soil physical and chemical properties and the influence of rice yield.[Result]Compared with treatment ①， treatments ② and ③ in the 0-20 cm soil layer can reduce the soil moisture content by 9.67% to 26.79%，soil bulk density increased by 0.08-0.16 g/cm3， and the difference reached a significant level， soil air permeability was improved， and soil porosity decreased by 3.05%-11.67%，the overall soil layers showed that the contents of organic carbon，total nitrogen and alkali hydrolyzed nitrogen gradually decreased， and the contents of organic matter， total nitrogen and alkali hydrolyzed nitrogen in the 0-10 cm soil layer were all lower than treatment ①;under the condition of treatment ②， the rice yield increased continuously for 2 years，and the yield increased by 4.91% and 9.54% in the first and second years respectively. Treatment ③had little effect on rice yield， and showed an increasing trend only in the second year， but the difference was not significant.[Conclusion]Subsoiling can increase the downward water permeability and bulk density of the paddy soil， and has little effect on soil organic matter and nitrogen， and can increase rice yield year after year.Although deep plowing can also improve the physical and chemical properties of the soil， it is less effective than deep loosening， and will reduce the fertility of the upper soil， and the increase in rice yield is not obvious.Key words Mechanization;Land preparation technology;Rice;Soil;Physical and chemical properties;Yield作者简介周秀梅（1976—），女，安徽合肥人，工程师，从事农业机械监管、农业机械新技术推广等工作。

高级英语(下)_习题集(含答案)

《高级英语（下）》课程习题集一、汉译英1.他们召开会议，研究该提升谁，别人准备并发布的声明上也要署上他们的名字。

2.她的头靠在窗帘上，鼻孔上是提花窗帘布上的尘土气。

3.通常电视画面凌驾于观点之上。

4.我们将感情建筑在原始的害怕、偏见和陈规老套上而不是建筑在知识和远见上。

5.他希望她不会太生气，因为她生气的时候他会想他当初该不该和她结婚，而有了这种怀疑使他感到很憋闷。

6.我受的是科学的教育，曾为一份科学刊物写过某个领域的一篇专题文章。

7.我们已总结出三种鲜明的价值准则，这样说是因为每种准则都引发出一种不同的顾客价值观8.我们以后的一切麻烦都来自于这个想法9.他很固执，和他从前一样，而且有点迟钝，但他已经准备要转过身来了10.几乎很想加上一句：没有什么东西不能引起人的势力感11.收集艺术作品是收集文化象征，而文化象征则还意味着社会声望。

12.观众中传出了因恐怖而倒吸气的声音，然后便是焦急的不停的窃笑13.寻找刺激是如此深刻的需要以至于手边没有无害途径，它便会找到这类有害途径来发泄。

14.但他们没能做到的是在任何一方面有所突破而达到新的高度。

15.可是如果人们吃葱头不是因为它们有葱头的味道，那么他们究竟为什么要吃洋葱？16.纪律在监督和激励着他们。

17.也许她再也看不到她做梦都没想过要与之分开的一切熟悉的东西了。

18.电视比报纸更依赖商业广告，既然广告是大生意，广告在本性上是亲共和党的。

19.衰老过程是人类生命周期中被忽视的非亲生儿。

20.此价值准则拥护者着重供应的不是市场所需的而是特定顾客群体所需的。

21.他站在大门口，尖顶帽推在后脑勺上，头发向前散乱垂在晒得黧黑的脸上。

22.当音乐中突然加进了萨克管，速度变快了，他小心地和她旋转起来，用自己的双肩打着拍子。

23.运作卓越的公司提供了质量、价格、购物便利的最佳组合，这是市场上其他公司无法与之相比的。

24.她没有把花放在车里带来，但她把花放在心中带来了。

成人高考成考英语(高起专)试卷及解答参考(2024年)

2024年成人高考成考英语(高起专)复习试卷及解答参考一、语音知识（本大题有5小题，每小题2分，共10分）1、Choose the word that has the same pronunciation as the word “elephant.”A. elephantB. elephantC. elephantD. elephantAnswer: BExplanation: The word “elephant” is pronounced as /ˈɛl.ɪ.fɑːnt/. Among the options provided, “elephant” in option B is pronounced the same as the original word.2、Select the word that has the opposite meaning of “increase.”A. increaseB. increaseC. decreaseD. decreaseAnswer: CExplana tion: The word “increase” means to make larger or greater. The wordthat has the opposite meaning is “decrease,” which means to make smaller or less. Among the options, “decrease” in option C is the correct answer.3、The word “communicate” is pronounced as:A. /kəˈmjuːnɪkeɪt/B. /kəˈmjuːnɪkeɪt/C. /kəˈmjuːniːkeɪt/D. /kəˈmjuːniːkeɪt/Answer: AExplanation: The correct pronunciation of “communicate” is /kəˈmjuːnɪkeɪt/. The “c” in “communicate” is not hard, as it does not precede a double vowel.4、Which of the following words has the correct pronunciation?A. “Environment” - /ɪnˌvaɪrənˈmeɪnt/B. “Education” - /ˌɛdʒuˈkeɪʃən/C. “Imagine” - /ɪˈmædʒɪneɪt/D. “Compass” - /kəˈmæpəs/Answer: BExplanation: The correct pronunciation of “education” is /ˌɛdʒuˈkeɪʃən/. The “e” in “education” is long, as it is followed by a “g” which is silent. The other options have mispronounced vowels or consonants.5、The sentence “She always has a smile on her face” emphasizes that sheis always __________.A. cheerfulC. nervousD. sadAnswer: A. cheerfulExplanation: The word “always” in the sentence indicates a constant state or behavior. The phrase “has a smile on her face” suggests that she is in a good mood or happy, which is best described by the word “cheerful.” The other options do not accurately capture the positive connotation of the sentence.二、词汇与语法知识（本大题有15小题，每小题2分，共30分）1、Choose the correct word or phrase to complete the sentence below.The_______of the meeting was quite impressive.A. atmosphereB. audienceC. attendanceD. occasionAnswer: CExplanation: The correct answer is “attendance” because it refers to the number of people who were present at the meeting. The other options do not fit the context of the sentence.2、Select the word that does not belong in the following list.A. enthusiasticC. exhaustedD. alertAnswer: CExplanation: The word “exhausted” does not belong in the list because it is an adjective that describes someone who is very tired, whereas “enthusiastic,” “energetic,” and “alert” all describe someone who is full of energy or has a positive, watchful attitude.3、Choose the word that best completes the sentence.The teacher___________the students to be quiet during the examination.A. requestedB. suggestedC. orderedD. recommendedAnswer: C. orderedExplanation: The correct choice is “ordered” because it indicates a direct command or instruction from the teacher. The other options, while they could be used in some contexts, do not convey the same level of authority or necessity as “ordered” does in this sentence.4、Complete the sentence using the correct form of the verb in parentheses.If you________(be) more careful, you would not have made so many mistakes.A. areB. wereC. will beD. had beenAnswer: B. wereExplanation: The correct form of the verb to use in this sentence is “were,” which i s the past subjunctive form of “to be.” The sentence is expressing a hypothetical situation, which is a situation that is not real but is being considered for the sake of argument. The past subjunctive is used to describea condition that is not true but could have been or would have been.5、Choose the word that best completes the sentence.The professor___________the students’ questions eagerly.A. ignoredB. addressedC. neglectedD. overlookedAnswer: B. addressedExplanation: The correct word to complet e the sentence is “addressed,” which means to speak to or write to someone formally or officially. The professor is expected to address the students’ questions, not ignore, neglect, or overlook them.6、Complete the sentence with the correct form of the verb in parentheses.They___________(be) discussing the project when the meeting was called toorder.A. wereB. had beenC. have beenD. isAnswer: A. wereExplanation: The correct form of the verb is “were,” which is the past continuous tense. The sentence describes an action that was happening at a specific past time (when the meeting was called to order), so the past continuous tense is appropriate. The other options are incorrect because they do not match the context or the tense required.7、Choose the word that best completes the sentence.The teacher was surprised by the student’s_ability to understand complex concepts.A)surpriseB)surprisedC)surprisingD)surpriseablyAnswer: C) surprisingExplanation: The correct answer is “surprising” because it is the adjective form that describes the student’s ability. “Surprise” is a noun, “surprised” is the past participle form of the verb, and “surpriseably” is not a word.8、Complete the sentence with the correct form of the given verb in brackets.They (be) (not) aware of the changes that (take) place in the company last month.A)wereB)areC)wasD)beAnswer: A) wereExplanation: The correct answer is “were” because the subject “they” is plural, and the past perfect tense “had taken” indicates that the cha nges occurred before the awareness of them. Therefore, “were” is the correct past tense form of “be.”9.Choose the word that best completes the sentence.I can’t believe how____________changes have occurred in this small town over the past decade.A)numerousB)rapidC)suddenD)gradualAnswer: D) gradualExplanation: The sentence is describing changes that have occurred over a period of time, suggesting a process that was not immediate or extreme. “Gradual” fits this context best, indicating changes that happen slowly over time.10.Select the correct form of the verb to complete the following sentence.The professor___________us a detailed outline of the research project before the deadline.A)gaveB)has givenC)will giveD)is givingAnswer: B) has givenExplanation: The sentence implies that the action of giving the outline has already occurred before the deadline. The present perfect tense (“has given”) is used to describe actions that have a present relevance or result.11.Choose the correct word to complete the sentence:The manager was_about the new project, but the team was confident.A)apprehensiveB)optimisticC)indifferentD)enthusiasticAnswer: A) apprehensiveExplanation: The correct answer is “apprehensive” because it means feeling or showing anxiety or fear about something, which fits the context of the manager being concerned about the new project. The other options do not convey the same sense of worry or anxiety.12.Select the word that is closest in meaning to the underlined word:The teacher’s_appr oach to teaching made the subject much more engaging.A)traditionalB)innovativeC)passiveD)objectiveAnswer: B) innovativeExplanation: The underlined word “innovative” means introducing new methods or ideas. The sentence suggests that the teacher’s approach was different and made the subject more engaging. The word “traditional” would imply a more conventional method, “passive” would suggest a lack of interest, and “objective” would imply a neutral approach, none of which fit the context as well as “innovative.”13.Choose the word that best completes the sentence.The company’s new policy has been widely __________, with both positive and negative reactions.A. criticizedB. implementedC. supportedD. rejectedAnswer: B. implementedExplanation: The correct word here should reflect that the policy has been put into effect. “Implemented” means to carry out or put into effect, which fits the context. “Criticized” would imply there are negative reactions,“supported” would imply positive reactions, and “rejected” wo uld imply outright refusal, none of which fully capture the act of the policy being put into practice.14.Select the correct form of the verb to complete the sentence.She_______(go) to the market every morning, but now she has a car.A. used to goB. uses to goC. used goD. uses goAnswer: A. used to goExplanation: The correct phrase to use in this context is “used to” followed by the base form of the verb, which indicates a past habit or practice that has since changed. “Used to go” is the correc t past simple form that indicates a habit in the past. The other options are grammatically incorrect or do not convey the intended meaning.15.Choose the correct word or phrase to complete the sentence.The professor___________the students to study hard for the exam.A. advisedB. recommendedC. suggestedD. proposedAnswer: B. recommendedExplanation: The correct answer is “recommended” because it is the most appropriate word to express the professor’s advice. “Advised,” “suggested,” and “proposed” can also mean giving advice or suggestions, but “recommended”is often used in a more formal context, such as in an academic setting.三、完形填空（30分）Passage:In the small town of Willow Creek, there was once a charming old library that stood at the heart of the community. The library was a hub of learning and culture, where people of all ages would gather to read, discuss, and exchange ideas. The librarian, Mrs. Thompson, was known for her warm smile and vast knowledge of books. She had been working at the library for over 30 years and was deeply loved by everyone in the town.One day, the town’s mayor announced that the library was in danger of closing due to budget cuts. The community was shocked and immediately rallied to save their beloved library. They organized a series of events, including a book sale, a bake sale, and a benefit concert, to raise funds.The most successful event was the “Willow Creek Reads” program, where local authors were invited to read to the children and talk about their writing process. The children were excited and inspired, and the adults were reminded of the power of books to bring people together.As the days went by, more and more people began to donate books and moneyto the library. Mrs. Thompson was overwhelmed by the outpouring of support from the community. She knew that the library would not only survive but thrive.One evening, as Mrs. Thompson was organizing a new shelf of donated books, she noticed a mysterious note tucked inside one of the books. The note read, “To Mrs.Thompson, from the Friends of Willow Creek Library. We hope these books bring you joy and continue to inspire the community.”Mrs. Thompson smiled, knowing that the spirit of the library was alive and well.Blanks:1.The library in Willow Creek was a___________of learning and culture.2.Mrs. Thompson was___________for her warm smile and vast knowledge of books.3.The town’s mayor announced that the library was in___________due to budget cuts.4.The community___________to save their beloved library.5.The most successful event was the___________program.6.The children were___________and inspired by the local authors.7.The adults were___________of the power of books to bring people together.8.More and more people began to___________books and money to the library.9.Mrs. Thompson was___________by the outpouring of support from the community.10.The note was a___________from the Friends of Willow Creek Library.11.Mrs. Thompson smiled, knowing that the spirit of the librarywas___________and well.Questions:11.What was the note a___________from the Friends of Willow Creek Library?A)InvitationB)ComplaintC)Thank youD)ApologyAnswer:C) Thank you四、阅读理解（本部分有5大题，每大题9分，共45分）第一题Read the following passage and answer the questions that follow.The Internet has revolutionized the way we communicate, access information, and conduct business. With just a few clicks, we can connect with people from all over the world, access a vast amount of information, and even conduct transactions online. However, along with these benefits, the Internet has also brought about various challenges and risks. One of the most significant risks is the potential for cybercrime, which includes hacking, identity theft, and phishing.1.What is one of the major risks associated with the use of the Internet?A. Improved communicationB. Access to a vast amount of informationC. Potential for cybercrimeD. Increased business opportunities2.What are some examples of cybercrimes mentioned in the passage?A. Hacking, identity theft, and phishingB. Improved communication and access to informationC. Increased business opportunitiesD. Reduced need for physical interaction3.How does the Internet impact the way we conduct business?A. It reduces the need for physical interactionB. It increases the potential for cybercrimeC. It provides a platform for global communication and transactionsD. It eliminates the need for traditional banking and financial servicesAnswers:1.C2.A3.C第二题Passage:The rapid development of technology has greatly influenced the way people communicate. Social media platforms have become an integral part of daily life,allowing individuals to connect with others across the globe. However, this shift in communication has raised concerns about the impact on face-to-face interactions and the potential loss of traditional social skills.One of the most popular social media platforms is Instagram, which is known for its focus on visual content. Users can share photos, videos, and stories, and follow others who share similar interests. While Instagram can be a great way to stay connected with friends and discover new things, it also has its downsides.A recent study found that excessive use of Instagram can lead to feelings of loneliness and depression. The constant comparison with others’ seemingly perfect lives can create a sense of inadequacy. Additionally, the platform’s algorithm can create a filter bubble, where users are only exposed to content that aligns with their existing beliefs and interests, thus limiting their exposure to diverse perspectives.Despite these concerns, many people find Instagram to be a valuable tool for networking and personal growth. It can provide a platform for artists, writers, and entrepreneurs to showcase their work and connect with potential audiences. Moreover, it can be a source of inspiration and motivation, as users are exposed to the achievements and stories of others.Questions:1、What is the main topic of the passage?A) The benefits of using social media platforms.B) The negative effects of Instagram on social interactions.C) The history of social media platforms.D) The role of technology in modern communication.2、Which of the following is NOT mentioned as a potential negative effect of using Instagram?A) Feelings of inadequacy.B) Limited exposure to diverse perspectives.C) Improved communication skills.D) Increased feelings of loneliness and depression.3、What is the author’s attitude towards Instagram?A) Highly critical.B) Indifferent.C) Positive and supportive.D) Ambiguous.Answers:1、B) The negative effects of Instagram on social interactions.2、C) Improved communication skills.3、D) Ambiguous.第三题Reading Passage:In the small town of Greenfield, there was a long-standing tradition of the annual Greenfield Festival. The festival, which took place every autumn, broughttogether local artists, musicians, and performers from around the region. It was a time for celebration, a showcase of local talent, and a chance for the community to come together and enjoy the arts.One of the highlights of the festival was the “Greenfield Talent Show,” where local residents could audition to perform. This year, the talent show had a special twist: the winner would receive a scholarship to study music at a prestigious music school in the nearby city of Bluewater.Word Count: 102Questions:1、What is the main purpose of the Greenfield Festival?A) To promote tourism in GreenfieldB) To bring the community together and celebrate local artsC) To raise funds for charityD) To promote agricultural products2、Which event at the festival was of particular interest to this year’s participants?A) The art exhibitionB) The music concertC) The Greenfield Talent ShowD) The local craft fair3、What reward did the winner of the Greenfield Talent Show receive?A) A cash prizeB) A trip to the nearby cityC) A scholarship to study musicD) A trophyAnswers:1、B) To bring the community together and celebrate local arts2、C) The Greenfield Talent Show3、C) A scholarship to study music第四题Reading ComprehensionRead the following passage and answer the questions that follow.The rise of e-commerce has revolutionized the way people shop and has had a significant impact on traditional brick-and-mortar stores. Online shopping has become increasingly popular due to its convenience and the vast variety of products available. However, this shift has also brought about challenges and changes in the retail industry.One of the main advantages of e-commerce is the convenience it offers. Customers can shop from the comfort of their own homes at any time of the day or night. This eliminates the need to travel to physical stores and wait in long queues. Additionally, online platforms often provide detailed product descriptions, customer reviews, and even virtual try-ons, which can help customers make more informed purchasing decisions.Despite these benefits, e-commerce has also presented challenges fortraditional retailers. Many have had to adapt to the changing landscape by investing in their online presence and offering competitive pricing and customer service. However, some have struggled to keep up and have been forced to close their doors.The retail industry is also witnessing a shift in consumer behavior. Customers are becoming more environmentally conscious and are increasingly looking for sustainable and ethical products. This has led to a rise ineco-friendly shopping options and a decline in demand for fast fashion.1.What is the main advantage of e-commerce mentioned in the passage?A) Competitive pricingB) ConvenienceC) Eco-friendly optionsD) Detailed product reviews2.How has e-commerce affected traditional brick-and-mortar stores?A) They have become more profitable.B) They have had to adapt and invest in online presence.C) They have seen a significant increase in foot traffic.D) They have closed down due to increased competition.3.What is the trend in consumer behavior mentioned in the passage?A) Customers are looking for more affordable products.B) Customers are becoming more environmentally conscious.C) Customers are preferring fast fashion over sustainable options.D) Customers are no longer interested in online shopping.Answers:1.B) Convenience2.B) They have had to adapt and invest in online presence.3.B) Customers are becoming more environmentally conscious.第五题Read the following passage and answer the questions that follow.In recent years, there has been a growing interest in online education. This shift is primarily due to the convenience and flexibility it offers to students. Online courses allow individuals to learn at their own pace, from any location, and often at a lower cost compared to traditional in-person classes. However, despite these advantages, online learning also comes with its own set of challenges.One of the main concerns is the potential for reduced social interaction. In traditional classrooms, students have the opportunity to engage with their peers and professors, which can enhance their learning experience. Online students, on the other hand, may feel isolated and disconnected from the academic community. This can lead to a lack of motivation and engagement in the course material.Another challenge is the need for self-discipline. Online courses require students to be self-motivated and organized. Without the structure of a traditional classroom, students must set their own schedules and manage their time effectively. This can be difficult for some individuals, especially thosewho are accustomed to the routine of attending classes on campus.Despite these challenges, many online learners find that the benefits outweigh the drawbacks. They appreciate the ability to work around their other commitments, such as full-time jobs or family responsibilities. Additionally, online courses often provide access to a wider range of resources and expertise than traditional courses.1.The primary reason for the growing interest in online education is:a) the opportunity for social interactionb) the flexibility and convenience it offersc) the lower cost compared to traditional in-person classesd) the access to a wider range of resources2.What is one of the main concerns mentioned about online learning?a) The convenience of learning at one’s own paceb) The potential for reduced social interactionc) The lower cost of online coursesd) The increased access to expertise3.According to the passage, which of the following is a challenge for online learners?a) The ease of engaging with peers and professorsb) The need for self-discipline and organizationc) The lower cost of online coursesd) The ability to work around other commitmentsAnswers:1.b) the flexibility and convenience it offers2.b) The potential for reduced social interaction3.b) The need for self-discipline and organization五、补全对话（本大题有5小题，每小题3分，共15分）第一题A: Excuse me, could you help me with some English vocabulary?B: Sure, I’d be happy to. What would you like to know about?A: I need to expand my vocabulary for the college entrance exam. Can you suggest some useful words for an “Adult Higher Education” (AHLE) English test?B: Absolutely! Here are a few words and phrases that are often included in such exams:1.(______) - a higher level of education beyond high school.2.(______) - a system of post-secondary education that allows working adults to earn degrees.3.(______) - a person who is studying or has studied at a college or university.4.(______) - a course or program of study that leads to a degree or certification.5.(______) - a test taken by students to gain admission to a college or university.A: Great, thanks! What should I write in the blank spaces?B:1.(______) - A higher level of education beyond high school.2.(______) - A system of post-secondary education that allows working adults to earn degrees.3.(______) - A person who is studying or has studied at a college or university.4.(______) - A course or program of study that leads to a degree or certification.5.(______) - A test taken by students to gain admission to a college or university.答案：1.Degree2.Adult Higher Education (AHLE)3.College student4.Curriculum5.Admission test解析：1.Degree - This word is used to describe a higher level of education, which is a key concept in the context of college education.2.Adult Higher Education (AHLE) - This specific term refers to the system that caters to working adults who wish to pursue further education.3.College student - This phrase describes someone who is currently or has been enrolled in a college or university.4.Curriculum - This word refers to the courses or program of study that an educational institution offers.5.Admission test - This term refers to the test that students must take to be admitted to a college or university, which is a common requirement for higher education.第二题1.A: I’m sorry, but I can’t help you with that right now.B: Why not?A: Because I’m currently in a meeting.B: Oh, I see. Well, can I leave you a message?A: Certainly, you can.B: Thank you. I’ll just write down my number and call you back after the meeting.A: That sounds good.B: Is there anything specific you need help with?A: Yes, actually. I need some information about the new software package our company is considering.B: Of course. Let me check if I have that information available.A: Alright, take your time.B: I should be able to find it for you. Just a moment, please.A: No problem.B: There we go. I have the information you need.A: Great, thanks. Can you send it to my email?B: Absolutely. I’ll send it over right now.A: Perfect. I appreciate your help.B: You’re welcome. Feel free to call back if you need anything else.A: Will do. Have a good meeting.B: You too. Goodbye.1.A: I’m sorry, but I can’t help you with that right now.B: Why not?A: Because I’m currently in a meeting.B: Oh, I see. Well, can I leave you a message?A: Certainly, you can.B: Thank you. I’ll just write down my number and call you back after the meeting.A: That sounds good.B: Is there anything specific you need help with?A: Yes, actually. I need some information about the new software package our company is considering.B: Of course. Let me check if I have that information available.A: Alright, take your time.B: I should be able to find it for you. Just a moment, please.A: No problem.B: There we go. I have the information you need.A: Great, thanks. Can you send it to my email?B: Absolutely. I’ll send it over right now.A: Perfect. I appreciate your help.B: You’re welc ome. Feel free to call back if you need anything else.A: Will do. Have a good meeting.B: You too. Goodbye.答案：解析：The correct continuation of the dialogue is B because it maintains the context of the original message and provides a logical progression of the conversation. It addresses the initial reason for the inability to assist and then moves on to offering a solution (leaving a message) and asking for further details about the assistance needed. The dialogue then proceeds with the person finding the information, offering to send it via email, and concluding with a friendly farewell.第三题A: Excuse me, I’m looking for the English section of the Adult College Entrance Examination. Can you help me?B: Sure, follow me. You need to go to the second floor and then turn right. The English section is located in Room 202.A: Oh, okay. Thank you. By the way, what time does the exam start?B: The exam will begin at 9:00 a.m. sharp. Make sure you arrive 30 minutes early to get settled.A: Got it. I’ll be there on t ime. One more thing, is there a specific roomfor the English exam?B: Yes, it’s Room 202 as well. You’ll see a sign indicating the English section.A: Perfect. Thanks again for your help.B: You’re welcome. Good luck with your exam!Answer:B: Yes, it’s Room 202 as well. You’ll see a sign indicating the English section.Explanation:In this dialogue, the student is asking for directions to the English section of the exam. The answer to the question is found in the response by the staff member. They confirm that the English exam is held in Room 202, as indicated by a sign, providing clear information to the student.第四题A: Excuse me, I seem to have misplaced my calculator. Can you help me find it?B: Sure, where do you think you might have left it?A: I was working on this problem for our math class, and I think I might have left it on the desk.B: Okay, let’s check the desk first. Is this the one you’re looking for?A: No, that’s not it. It was smaller and black.B: Alright, let’s look over there by the window. Do you see anything that。

The Effect of Discourse Markers on the Comprehension of Lectures

Applied Linguistics, VoL 7, No. 2,0 Oxford University Press, 1986
114
DISCOURSE MARKERS AND THE COMPREHENSION OF LECTURES
consequences. Comprehension is viewed as a combination of both bottom-up and top-down processing. As Adams and Collins put it (1979):
The Effect ofDiscourse Markers on the Comprehension ofLectures*
CRAIG CHAUDRON AND JACK C. RICHARDS
University of Hawaii at Manoa INTRODБайду номын сангаасCTION
With greater numbers of non-native speakers of English entering Englishmedium institutions of higher education around the world, the provision of appropriate English-language training as a preparation for academic study becomes increasingly important. In the United States, all major universities now offer specialized English language courses for foreign students, dealing with the use of English in such areas as advanced reading, writing term papers, discussion skills, lecture comprehension, and note taking. The growing demand for such courses has led to the need for research into the processes underlying academic performance in a second or foreign language, which can provide input to teacher training as well as to the development of appropriate curriculum and instructional materials. This paper deals with the university lecture and describes a study which was conducted to investigate how different categories of discourse markers affect the degree to which foreign students understand university lectures.

舌尖效应专业英语作文

舌尖效应专业英语作文Title: The Tongue's Edge: Exploring the Culinary Delights Through the Lens of Gastronomy。

The concept of the "Tongue's Edge Effect" is a captivating exploration into the intricate world of gastronomy. This phenomenon delves deep into the multifaceted layers of taste, culture, and tradition, encapsulating the essence of culinary artistry. In this essay, we will embark on a journey to unravel the nuances of this phenomenon, delving into its significance in the realm of professional culinary discourse.At its core, the "Tongue's Edge Effect" epitomizes the sensory experience of savoring exquisite cuisines, transcending mere gustatory perception to evoke profound emotional and cultural resonance. It encompasses the interplay of flavors, textures, and aromas, orchestrating a symphony of sensations that titillate the palate and captivate the senses.In the realm of professional gastronomy, this phenomenon holds immense significance as it underscores the mastery of culinary craftsmanship and the art of flavor composition. Chefs strive to harness the "Tongue's Edge Effect" to create culinary masterpieces that not only satiate hunger but also stimulate the mind and nourish the soul.One of the key elements of the "Tongue's Edge Effect" is its ability to transcend cultural boundaries and foster cross-cultural appreciation. Through the exploration of diverse cuisines and culinary traditions, individuals are afforded the opportunity to embark on a sensory odyssey, immersing themselves in a tapestry of flavors that reflect the rich tapestry of human civilization.Moreover, the "Tongue's Edge Effect" serves as a catalyst for culinary innovation, inspiring chefs to push the boundaries of creativity and experimentation. By incorporating novel ingredients, techniques, and presentation styles, culinary artisans can creategastronomic marvels that challenge convention and redefine the culinary landscape.In addition to its aesthetic appeal, the "Tongue's Edge Effect" also holds profound implications for health and wellness. By emphasizing the importance of mindful eating and sensory awareness, individuals can cultivate a deeper connection with their food, fostering a sense of gratitude and reverence for the nourishment it provides.Furthermore, the "Tongue's Edge Effect" underscores the interconnectedness of food and culture, highlighting the role of cuisine as a conduit for social cohesion and cultural exchange. Through communal dining experiences and culinary rituals, individuals are able to forge meaningful connections and celebrate the rich diversity of human expression.In conclusion, the "Tongue's Edge Effect" represents a fascinating intersection of sensory perception, cultural heritage, and culinary innovation. As we continue to explore the depths of gastronomy, let us embrace thetransformative power of taste and savor the myriad delights that the culinary world has to offer.。

土壤耕作方式对冬小麦根系生理特性的影响

摘要：为了明确轮耕对土壤小麦根系活力和活跃吸收面积比例的影响，2020~2021年小麦季，在辛集市马兰农场，通过大田试验方式，选择前期已进行耕作处理连续3a 的麦田进行不同的土壤耕作方式处理，耕作方式设连年深松（S ）、隔年深松（SR ）、隔2a 深松（SRRS ）和连年旋耕（R ，CK ）4个处理，测定了各土壤耕作方式下不同土层深度的小麦根系活力和活跃吸收面积比例，并分析了小麦根系活力与根系活跃吸收面积比例的相关性。

结果表明：（1）旋耕或旋耕/深松交替的地块，均有利于提高0~15cm 土层的小麦根系活跃吸收面积比例；而深松/旋耕交替，尤其是隔年深松，有利于提高15~45cm 土层的小麦根系活跃吸收面积比例。

（2）旋耕（R ）有利于提高0~15cm 土层土壤的小麦根系活力，而旋耕与深松交替（SR 或SRRS ）处理则利于提高15~60cm 土层的小麦根系活力，平均较单独深松或旋耕处理提高33.3%和16.9%。

（3）根系活力在不同土层相关性较高，上层与下层根系活力具有显著正相关（平均r 为0.68~0.90）；活跃根系吸收面积比例在上下土层之间相关性较差。

在连续采用小麦季旋耕、玉米季免耕的小麦—玉米一年两熟种植区，隔年深松可有效提高小麦根系活力，增大小麦根系活跃吸收面积的比例，具备大面积推广应用的潜力。

关键词：冬小麦；土壤耕作方式；根系活力；根系活跃吸收面积中图分类号：S512.1文献标识码：A 文章编号：1008-1631（2023）06-0035-06收稿日期：2023-07-17基金项目：“十三五”国家重点研发计划项目（2018YFD0300505）作者简介：于丽娜（1982-），女，河北安平人，高级农艺师，主要从事农业技术推广工作。

E-mail ：****************。

通讯作者：尹宝重（1981-），男，河北沧县人，副教授，博士，主要从事植物病害生态学研究。

E-mail ：yinbaozhong@ 。

农业英语练习参考答案

Unit1 Text AText-related exercisesI.1. Agronomy is the science and technology of producing and using plants for food, fuel, fiber, and reclamation2. They are involved with any issues including producing food, creating healthier food, managing environmentalimpact of agriculture, and creating energy from plants.3. To produce the best crops under various conditions.4. By change the genetics of the plants.5. In labs6. Compounds of nitrogen, phosphorus, and potassium.7. Contour plowing.8. Sustainable agriculture, organic farming, alternative food systems and the development of alternative croppingsystems.9. Quantitively.10. Four to twelve years.II.1. 作物育种2. 轮作，轮种3. 植物生理学4. 有机耕作5. 杂草控制，除草6. plant genetics7. selective breeding8. contour plowing9. soil fertility 10. （insect and）pest control III.1. plants2. combines3. healthier4. agriculture5. genetics6. yields7. nutritional8. civilization9. security 10. resistantIV.1. Agronomic/Agricultural biotechnology is increasingly being used applied for novel/new uses other than food.2. Agronomy involves with biology, ecology, chemistry and other sciences.3. Selective breeding of plants is to produce/develop/breed the best crops adapted to different environments andgrowing conditions.4. Agronomists often specialize in areas such as crop rotation, soil classification, weed control and insect andpest control.5. Agroecology studies the management of agricultural system on ecological and environmental perspetives. Theme-related ExercisesI.1-6 F T F T F FII.1. M potential2. K adoption3. I acute4. H combine5. F work6. G actively7. D optimally8. C initiative9. N available 10. A promoteText BText-related exercisesI.1. Ki ll pests’ natural enemies and their overuse can harm farmers, consumers and the environment.2. When the natural processes of pest regulation break down.3. Ecosystem approach4. To manage insect pest populations to the point where natural predation operates in a balanced way and croplosses to pests are kept to an acceptable minimum5. More than/exceed US $40 billion6. Almost the same/ little change. 30-40 percent.7. Less than 1%. The rest contaminates/pollutes the air, soil and water.8. Urban and peri-urban horticulture9. Because the pesticides are aggressively marketed.10. In 1960s. IPM has been based on ecology, the concept of ecosystems and the goal of sustaining ecosystemfunctions.II.a -- 3,b -- 6,c -- 1,d -- 2,e -- 7,f -- 4,g -- 5III.1. option2. contaminates3. negative4. vicious cycle5. Pesticide6. excessive7. Health8. Occupational9. pesticide residues 10. ecosystemsIV.1.The risks posed by pesticides to health and the environment have aroused public concernsworldwide/globally.2. Before the Industrial Revolution farming was a labor-intensive industry, and the vast majority of the humanpopulation labored in agriculture3. Usually proper use of pesticides can, to some extent, keep pests in check.4. Over-reliance on pesticides contributes to a vicious cycle of resistance in pests.5. Excessive use of pesticide exposes farmers to serious health risks and has negative consequencesfor/effects/influences on/ the environment.Theme-related ExercisesI.1-5 A C D B CII.作为基于生态系统的战略，病虫害综合治理在世界农业发展中已取得了一些显著的成绩。

Impact of nitrogen fertilization and soil tillage on arbuscular mycorrhizal fungal communities

Impact of nitrogen fertilization and soil tillage on arbuscular mycorrhizal fungal communities in a Mediterranean agroecosystem Luciano Avio a,Maurizio Castaldini b,Arturo Fabiani b,Stefano Bedini c,Cristiana Sbrana a, Alessandra Turrini c,Manuela Giovannetti c,*a Istituto di Biologia e Biotecnologia Agraria CNR,AT Pisa,Via del Borghetto80,56124Pisa,Italyb Consiglio per la Ricerca e Sperimentazione in Agricoltura,Centro di Ricerca per l’Agrobiologia e la Pedologia CRA-ABP,Piazza Massimo D’Azeglio30, 50121Firenze,Italyc Dipartimento di Scienze Agrarie,Alimentari e Agro-Ambientali,Universitàdi Pisa,Via del Borghetto80,56124Pisa,Italya r t i c l e i n f oArticle history:Received14March2013Received in revised form5September2013Accepted9September2013 Available online20September2013Keywords:Arable systemsArbuscular mycorrhizal fungiN-fertilizationTillagePCR e DGGEFungal diversityTrap cultures a b s t r a c tThe impact of nitrogen(N)fertilization and tillage on arbuscular mycorrhizal fungi(AMF)was studied in a Mediterranean arable system by combining molecular,biochemical and morphological analyses ofﬁeld soil and of soil and roots from trap plants grown in microcosm.Canonical correspondence analysis(CCA) of PCR e DGGE banding patterns evidenced that AMF communities in theﬁeld are affected by N-fertil-ization and tillage.N-fertilization was also the main factor shaping AMF communities in Medicago sativa trap plant soil and roots.The overall sporulation pattern of the different AMF species showed a pre-dominant effect of tillage on AMF communities,as shown by CCA analysis.Funneliformis mosseae was the predominant species sporulating in tilled soils,while Glomus viscosum and Glomus intraradices prevailed in no-tilled soils.Field glomalin-related soil protein content was reduced by tillage practices.Our multimodal approach,providing data on two main production factors affecting soil AMF communities, may help implementing effective agricultural management strategies able to support the beneﬁcial relationship between crops and native AMF symbionts.Ó2013Published by Elsevier Ltd.1.IntroductionArbuscular mycorrhizal(AM)fungi(AMF)establish symbiotic associations with most crop plants and play a fundamental role in plant growth,soil fertility and productivity,delivering many essen-tial ecosystem services(Gianinazzi et al.,2010).AM fungal hyphae spread from host roots to the surrounding soil,developing an extensive mycelial network,crucial to the uptake of nutrients,mainly phosphorus(P),nitrogen(N),copper(Cu)and zinc(Zn)(Giovannetti and Avio,2002;Smith and Read,2008;Blanke et al.,2011).Many AM fungal isolates increase plant tolerance to root pathogens,pests and abiotic stresses,such as drought and salinity(Augé,2001;Evelin et al.,2009;Sikes et al.,2009)and increase the synthesis of beneﬁ-cial plant secondary metabolites,thus contributing to the production of safe and high quality food(Ceccarelli et al.,2010;Giovannetti et al., 2012).Moreover,AMF contribute to soil carbon(C)sequestration and organic matter conservation by means of the extensive mycelial network producing large quantities of a sticky proteinaceous hydrophobic substance,glomalin,that accumulates in soil as glomalin-related soil protein(GRSP)(Rillig and Mummey,2006; Bedini et al.,2009),and of other recalcitrant polymers,such as chitin and chitosan(Zhu and Miller,2003;Fortuna et al.,2012).Several studies have demonstrated that different crop man-agement systems involving high intensity of mechanization or high inputs of chemicals may affect AMF species composition or show a negative impact on AMF spore abundance and mycorrhizal colo-nization,often leading to a reduction of AMF beneﬁts to crop pro-duction and soil quality(Douds et al.,1995;Jansa et al.,2002,2003; Oehl et al.,2004;Castillo et al.,2006;Brito et al.,2012).Indeed, deep ploughing,by disrupting the hyphae of the mycorrhizal network(Kabir,2005),may differentially affect AMF taxa,which show differential activity and functioning(Klironomos,2003; Munkvold et al.,2004;Avio et al.,2006).On the other hand,soil chemical fertilization may affect AMF growth and colonization ability by altering the concentration of soil mineral nutrients and shifting the N:P ratio of plant tissues,which in turn may stimulate the growth of AMF populations more adapted to the new nutri-tional conditions(Johnson et al.,2003;Na Bhadalung et al.,2005; Toljander et al.,2008).*Corresponding author.Tel.:þ390502216643;fax:þ390502216641.E-mail address:mgiova@agr.unipi.it(M.Giovannetti).Contents lists available at ScienceDirectSoil Biology&Biochemistry journal h omepage:www.elsevier.co m/lo cate/soilbio0038-0717/$e see front matterÓ2013Published by Elsevier Ltd./10.1016/j.soilbio.2013.09.005Soil Biology&Biochemistry67(2013)285e294The data available on the impact of different levels of tillage and chemical fertilization on AMF community composition and dy-namics indicate that such major production factors should be tested in dedicated experimental arable systems,in order to reach a better understanding of the driving forces that shape AM fungal communities(Moebius-Clune et al.,2013a)and to implement effective agricultural management strategies supporting crop plant-beneﬁcial soil microorganisms.A comprehensive and exhaustive evaluation of changes in AMF community diversity produced by anthropogenic and environmental variables may be difﬁcult to accomplish utilising singular approaches.Actually, morphological analyses based on spores collected in theﬁeld may miss non sporulating species or those represented by old and parasitized spores,while root DNA analyses may reveal only the ampliﬁable DNA,representing a subset of AMF communities colo-nizing the sampled roots,which may differ from those detected in rhizosphere or bulk soil and from those described using morpho-logical analyses as well(Hempel et al.,2007;Cesaro et al.,2008; Mirás-Avalos et al.,2011).The aim of the present study was to evaluate the impact of N-fertilization and tillage on AMF abundance and diversity,focussing on a long-term experimental site in a Mediterranean arable system. To this aim,we combined molecular,biochemical and morpho-logical analyses to assess:i)AMF diversity inﬁeld soil,by means of polymerase chain reaction(PCR)e denaturating gradient gel elec-trophoresis(DGGE)analysis of18S rRNA gene fragments,a mo-lecularﬁngerprinting technique widely used to detect the modiﬁcations induced by different factors on soil microbes(Smalla et al.,2001;Castaldini et al.,2005;Oliveira et al.,2009);ii)AMF abundance and diversity,by means of morphological and molecular identiﬁcation of spores produced in trap plants grown in micro-cosm,a technique providing newly produced spores suitable for morphological identiﬁcation(Oehl et al.,2003,2004;Yao et al., 2010);iii)AMF diversity in soil and roots of trap plants,by means of PCR e DGGE analysis of18S rRNA gene fragments;iv)GRSP con-tent inﬁeld and trap cultures soil.2.Materials and methods2.1.Study site and soil samplingThe study was conducted at the“Pasquale Rosati”experimental farm near Agugliano,Italy(43 320N,13 220E,100m a.s.l.,slope10%). The soil is a calcaric gleyic cambisol almost free of gravel,with a high clay and calcium content.The climate is dry-summer subtropical (Mediterranean),with a mean annual rainfall in the period1998e 2008of786mm.The highest mean monthly temperature(30.6 C) and the lowest precipitation(35mm)occurred in July.The lowest mean monthly temperature(3.0 C)occurred in January and the highest precipitation(105mm)in September(De Sanctis et al.,2012). The experimental site belong to a long-term tillage experiment, established in1994,with a two year rotation of maize(Zea mays L.) and durum wheat(Triticum durum L.)since2002,and designed as a split plot with tillage treatments assigned to the main plots(each 1500m2in size)and N-fertilization treatments assigned to subplots (each500m2in size).The experiment was replicated in two blocks with treatments repeated in the same plots every year.In the present study,soil sampling was performed in the subplots treated with no N-fertilization(0)and90kg haÀ1N(90)as ammonium nitrate,both in the conventional tillage(CT)and in the no tillage(NT)treatment. CT treatment consisted of ploughing at a depth of40cm and double harrowing before sowing,whereas NT plots were left undisturbed except for sod seeding,crop residuals and weed chopping and total herbicide spraying prior to seeding.For data on crop yield and soil characterisation,see De Sanctis et al.(2012).After wheat harvest the experimental area was sampled in Autumn2006by randomly collecting four15cm deep soil cores from each of the eight subplots.The four soil cores were pooled to obtain samples of about2.0kg which were air-dried and stored at 4 C until processed.Two hundred grams of each sample were used for GRSP analysis and the remaining soil for establishment of trap cultures.Forﬁeld soil DNA analysis,soil samples(three replicates) were taken from one subplot of the four relevant treatments,for a total of twelve samples,then stored atÀ20 C until processed.2.2.Trap cultures and spore analysisEach soil sample was mixed,1:1by volume,with Terragreen (calcined attapulgite clay,Oil Dri,Chicago,IL),and poured into four 750cm3plastic pots,two for each of the two trap plant species utilized,Z.mays and Medicago sativa L.Plants were grown in glasshouse,under ambient natural light and temperature condi-tions and supplied with tap water as needed.In addition,they received weekly fertilization with half strength Hoagland’s solution (10mL per pot).After six months’growth,three soil samples(10g each)were collected from each pot and processed.AMF spores and sporocarps were extracted by wet-sieving and decanting,using a set of nested sieves,down to a mesh size of50m m(Gerdemann and Nicolson,1963),thenﬂushed into Petri dishes and examined under a dissecting microscope(Wild,Leica,Milano,Italy).The spores were separated into groups,according to their morphology.Spores were isolated by using capillary pipettes,mounted on microscope slides in polyvinyl alcohol lacto-glycerol(PVLG)and in PVLGþMelzer’s reagent(1:1,v:v)and examined under a Polyvar light microscope (Reichert-Young,Vienna,Austria).Qualitative spore traits(spore shape,colour and size,spore wall structure and shape,colour and size of the subtending hypha)were examined on at least50spores for each morphotype.Morphotype identiﬁcations were based on original descriptions and current species descriptions available online(International Culture Collection of(Vesicular)Arbuscular Mycorrhizal Fungi[/fungi/taxonomy/ speciesID.htm];Prof.Janusz Blaszkowski website at Szczecin University[.pl/Glomeromycota/]).Since important changes of AMF nomenclature have been recently pro-posed by different authors(Oehl et al.,2011;Krüger et al.,2012), with some taxa inconsistently named,we utilized the new bi-nomials for consistent names and maintained the previous ones for the others.After sixteen months’growth,three soil samples were collected from each pot and processed as described above,with the aim of retrieving also late sporulating AMF species(Oehl et al.,2009).The data reported are from such a sampling.2.3.Field soil DNA extractionDNA extraction was performed on500mg of eachﬁeld soil sample,with the FastDNAÒSpin Kit for Soil(MP Biomedicals,Solon, OH)according to manufacturer’s instructions,with minor modiﬁ-cations:a double homogenization in the FastPrepÒInstrument(MP Biomedicals)for30s at a speed setting of6.0and25s at a speed setting of6.5,and aﬁnal resuspension in100m L of TE buffer(10mM Tris e HCl,0.1mM EDTA pH8).The DNA was then puriﬁed with the DNA Clean Up Spin Kit(GENOMED GmbH,Löhne,Germany),ac-cording to manufacturer’s instructions.2.4.DNA extraction from roots and soil of trap culturesSoil and roots of Z.mays and M.sativa were collected from trap cultures six months after establishment.Three samples of roots (100mg)and soil(500mg)were utilized for each plant species andL.Avio et al./Soil Biology&Biochemistry67(2013)285e294 286treatment.Root DNA was extracted in liquid nitrogen using DNeasy Plant Mini Kit(QIAGEN GmbH,Hilden,Germany),according to the manufacturer’s protocol.Soil DNA was extracted as described above.2.5.DNA extraction from sporesIntact,healthy spores belonging to the following morphospecies were isolated from trap cultures six months after establishment and utilized for DNA extraction:a)Glomus viscosum T.H.Nicolson (pools of spores);b)Glomus intraradices N.C.Schenk&G.S.Sm. (pools of spores);c)Funneliformis mosseae(T.H.Nicolson&Gerd.)C. Walker&A.Schüssler(single spores and sporocarps).Spores and sporocarps were manually collected with a capillary pipette under the dissecting microscope and cleaned by sonication(120s)in a B-1210cleaner(Branson Ultrasonics,Soest,NL).After three rinses in sterile distilled water(SDW),spores and sporocarps were surface sterilized with2%Chloramine T supplemented with streptomycin (400m g mLÀ1)for20min and rinsedﬁve times in SDW.Spore clusters,spores and sporocarps were selected under the dissecting microscope and transferred in Eppendorf tubes before DNA extraction(Redecker et al.,1997).2.6.DNA ampliﬁcationAliquots of soil DNA(50ng)were used to amplify the V3e V4 region of18S rDNA using the universal eukaryotic NS31GC primer (Kowalchuk et al.,2002)and the AM1primer(Helgason et al.,1998) in a50m L PCR mix consisting of250m M each primer,250m M each dNTP,1.5mM MgCl2,1ÂBuffer(67mM Tris e HCl pH8.8;16.6mM (NH4)2SO4;0.01%Tween-20)and2.5U of Taq DNA Polymerase (Polymed,Firenze,Italy).The reaction was performed in a iCycler thermal cycler(Bio-Rad Laboratories Inc.,Hercules,CA)with a protocol consisting of an initial cycle of95 C for3min,followed by 35cycles of94 C for30s,62.3 C for45s and72 C for60s,and a ﬁnal extension step at72 C for7min.Each sample was ampliﬁed three times and the amplicons were pooled together before DGGE analysis.Root and fungal spore DNA ampliﬁcations were performed in the same conditions,except for the starting material(25ng),and for annealing time of spore samples(60s).2.7.Double gradient DGGE analysis of AMF communitiesThe analysis was performed with the INGENYphorUÒsystem (Ingeny International BV,Goes,The Netherlands)on a5e6%poly-acrylamide gel(acrylamide/bis37.5:1),under denaturation condi-tions(urea,7M;40%formamide with a denaturing gradient ranging from25to50%);the gels were run in1ÂTAE buffer at75V for17h at60 C and were stained with14mL of1ÂTAE containing 1.4m L of SYBRÒGold(Molecular Probes,Inc.,Eugene,OR)(dilution 1:10,000)for30min in the dark.Visualization and digital pictures were performed with a ChemiDoc System(Bio-Rad Laboratories). Using electrophoretic patterns,a matrix of the presence and absence of bands was obtained by GelCompar II 4.6software (Applied Maths NV,Sint-Martens-Latem,Belgium).2.8.Cloning and sequencing of18S rDNA fragmentsSelected PCR e DGGE bands pertaining to spores or roots samples were excised from the gel,resuspended in30m L of sterile TE and stored atÀ30 C.The DNAs extracted from the DGGE bands were re-ampliﬁed with the primers NS31GC and AM1and the PCR products were loaded onto a new DGGE gel to ensure the purity of each single band.The amplicons were then cloned into a pCRÒ4-TOPOÒvector using TOPO TA CloningÒkit for Sequencing(Invitrogen Corporation, Carlsbad,CA)and sequenced using the M13primer.Sequencing was carried out at the C.I.B.I.A.C.I.(University of Florence)using the ABI PRISMÒBigDyeÒTerminator v1.1Cycle Sequencing Kit(Applied Biosystems,Foster City,CA)according to the manufacturer’s recommendations.The parameters for cycle sequencing in the thermocycler Primus96plus(MWG Biotech, Ebersberg,D)were18s delay at96 C,followed by25cycles with 18s at96 C,5s at50 C and4min at60 C.Electrophoresis was performed on an ABI Prism310CE system(Applied Biosystems).2.9.Phylogenetic analysisSequences were entered in the BLASTn program of National Center for Biotechnology Information GenBank database(http:// /)to search for closely related sequences. Before phylogenetic analysis,sequences were screened with Chimera Check version2.7(Cole et al.,2003)(http://rdp.cme.msu. edu)and aligned with ClustalW program(Chenna et al.,2003), using Glomeromycota sequences available in GenBank.The phylogenetic tree was inferred by neighbour joining(NJ)method using Kimura2-parameter in TREECON for Windows software(Van de Peer and De Wachter,1994).The conﬁdence of branching was assessed using1000bootstrap resamplings.The sequences were deposited at EMBL Nucleotide Sequence Database(/ embl/)under the accession numbers HE806381e HE806417.2.10.GRSP analyses ofﬁeld and trap culture soilGRSP was extracted from soil using the procedures described by Wright and Upadhyaya(1996)for easily extractable(EE-GRSP)and total(T-GRSP)GRSP.EE-GRSP analyses were carried out onﬁeld soil and on six months’old trap cultures.Brieﬂy,EE-GRSP was extracted from1g of2mm-sieved soil with8mL of a20mM citrate solution, pH7.0,by autoclaving at121 C for30min.T-GRSP was extracted from1g of2mm-sieved soil samples,by repeated cycles with 50mM citrate,pH8.0,by autoclaving at121 C for60min.Ex-tractions of samples continued until the supernatant content of GRSP was under method detection limits(2mg mLÀ1).Superna-tants from each cycle were collected after centrifugation at10,000g for10min to pellet soil particles,pooled and stored at4 C until analysed.Protein content was determined by Bradford assay (Sigma e Aldrich,Inc.)with bovine serum albumin as the standard. Each determination was repeated three times.2.11.Statistical analysisData of spore counts and GRSP concentrations were analysed on IBM SPSS19.0software(SPSS Inc.,Chicago,IL).The GLM Univariate procedure was utilized to investigate the effects of tillage man-agement,fertilization levels,and host plants in trap cultures,as ﬁxed factors,and their interactions,with block as random factor. Canonical correspondence analysis(CCA)was performed by using PAST1.99software(Hammer et al.,2001),on the presence/absence matrix based on DGGE banding pattern and on spore numbers after logarithmic transformation.Permutation test(n¼1000)was per-formed by using PAST software.3.Results3.1.PCR e DGGE analyses of AM fungal diversity inﬁeld soil and trap culturesCCA revealed a signiﬁcant effect of N-fertilization on AMF communities of theﬁeld plots(P¼0.007).Theﬁrst canonical axisL.Avio et al./Soil Biology&Biochemistry67(2013)285e294287explained 86.2%of the cumulative variance of PCR e DGGE banding patterns data,and the second one explained the remaining 13.8%(Fig.1).CCA showed an additional effect of tillage on AMF com-munity diversity (Fig.1).PCR e DGGE pro ﬁles of AMF communities occurring in the soil of trap cultures from different treatments were always more dissim-ilar than pro ﬁles from the same treatment (Fig.2).CCA suggests a separation of AMF soil (0N)communities of M.sativa and Z.mays trap plants,though not statistically signi ﬁcant (P ¼0.172)(Fig.3).N-fertilization was the main factor affecting AMF communities occurring in M.sativa trap soil,as revealed by CCA of the relevant PCR e DGGE pro ﬁles,showing a clear-cut separation between pat-terns obtained from N-fertilized and unfertilized soil (P ¼0.009)(Fig.4A).A minor effect of tillage treatments was found (Fig.4A).The ﬁrst canonical axis explained 90.1%of the cumulative variance of PCR e DGGE banding patterns data,and the second one explained the remaining 9.9%(Fig.4A).Consistent results were obtained by CCA of AMF communities occurring in M.sativa roots (P ¼0.002)(Fig.4B).3.2.Analyses of DNA sequencesNS31-GC/AM1amplicons obtained from plant roots,spores and sporocarps of trap cultures of unfertilized plots generated multiple PCR e DGGE bands,which,after excision from the gel,cloning and-1-0.500.511.52-1.8-1.4-1-0.6-0.20.20.611.41.8A x i s 2 (13.8%)Axis 1 (86.2%)CT0CT90NT0NT90TillageFertilizationCT0CT0NT0NT0NT90NT90CT90CT90Fig.1.Canonical correspondenceanalysis (CCA)biplot of V3e V4region of nuclear 18S rDNA PCR e DGGE fragments from three replicates of ﬁeld soil from conventionally tilled (CT)and no tilled (NT)plots fertilized with 0(NT0,CT0)or 90(NT90,CT90)kg ha À1N.Fig.2.PCR e DGGE pro ﬁles of V3e V4region of nuclear 18S rDNA fragments from roots of Medicago sativa (M)trap cultures from conventionally tilled (CT)and no tilled (NT)plots fertilized with 0(NT0,CT0)or 90(NT90,CT90)kg ha À1N.-0.8-0.6-0.4-0.20.00.20.40.60.81.0-0.7-0.5-0.3-0.10.10.30.50.7A x i s 2 (0.9%)Axis 1 (99.1%)NT0MNT0ZCT0MCT0Z TillageHostNT0MNT0MCT0MCT0M CT0ZCT0ZNT0ZNT0ZFig.3.Canonical correspondence analysis (CCA)biplot of V3e V4region of nuclear 18S rDNA PCR e DGGE fragments from three replicates of trap culture soil from unfertilized no tilled (NT0)and conventionally tilled (CT0)plots,with Medicago sativa (M)and Zea mays (Z)as host plants.-1-0.8-0.6-0.4-0.200.20.40.60.8-1.2-0.8-0.400.40.8 1.2A x i s 2 (9.9%)Axis 1 (90.1%)NT90NT90NT90NT0NT0NT0CT0CT0CT0CT90CT90CT90TillageFertilizationA-1-0.8-0.6-0.4-0.200.20.40.60.811.2-1.4-1.0-0.6-0.20.20.6 1.01.4A x i s 2 (7.0%)Axis 1 (93.0%)NT0NT0NT0CT0CT0CT0CT90CT90CT90NT90NT90NT90TillageFertilizationBFig.4.Canonical correspondence analysis (CCA)biplot of V3e V4region of nuclear 18S rDNA PCR e DGGE fragments from (A)soil and (B)roots of Medicago sativa (M)trap cultures from conventionally tilled (CT)and no tilled (NT)plots fertilized with 0(NT0,CT0)or 90(NT90,CT90)kg ha À1N.L.Avio et al./Soil Biology &Biochemistry 67(2013)285e 294288sequencing,yielded a total of 37sequences with high similarity (98e 100%identity)to those of Glomeromycota,after BLASTn searches in GenBank databases.Only two sequences matched with Ascomycota sequences.PCR e DGGE bands obtained from M.sativa and Z.mays roots yielded 20sequences which grouped into four Glomeromycota sequence types,showing identities with sequences of both cultured and uncultured AMF deposited in GenBank databases.In particular,we recovered two sequence types,clustering with sequences of F.mosseae (Ag1sequence type)and G.intraradices /Glomus fas-ciculatum (Thaxt.)Gerd.&Trappe/Glomus irregulare B 1aszk.,Wubet,Renker &Buscot group,hereafter G.intraradices (Ag3sequenceFig.5.Neighbour-joining phylogenetic tree of glomeromycotan sequences derived from PCR e DGGE bands obtained from Medicago sativa and Zea mays trap plants.The analysis is based on V3e V4region of nuclear 18S rDNA sequences,and the tree is rooted with a reference sequence of Geosiphon pyriformis (X86686).Bootstrap values (>70%)were determined for neighbour joining (1000resamplings).Different sequence types are indicated in brackets:Ag1,Agugliano1;Ag2,Agugliano2;Ag3,Agugliano3;Ag4,Agugliano4;Ag5,Agugliano5.Sequences obtained in the present study are shown in bold with their accession numbers (HE806381e HE806417)followed by their DNA source (spores,spo-rocarps,roots)and treatment (trap cultures from conventionally tilled (CT)and no tilled (NT)plots fertilized with 0(NT0,CT0)kg ha À1N),with Medicago sativa (M)or Zea mays (Z)as trap plant.L.Avio et al./Soil Biology &Biochemistry 67(2013)285e 294289type)(Fig.5).Two other sequence types,Ag4and Ag5,which matched (99%identity)with sequences of uncultured Glomus species already present in GenBank were found (Table 1).Ag1and Ag3sequences were retrieved from all Z .mays and M.sativa roots,with the exception of M.sativa roots of NT0trap cultures,where Ag1was absent.Ag5sequences were retrieved from all trap cul-tures roots,while Ag4sequence type were found only in M.sativa roots,irrespective of the treatment (Fig.5).No sequences of G.viscosum were retrieved from trap plant roots.Blast and phylogenetic analyses of sequences derived from the ampli ﬁcation of spores and sporocarps lead to the identi ﬁcation of three separate clusters,Ag1(11sequences),Ag2(4sequences)and Ag3(2sequences),corresponding to F .mosseae ,G.viscosum and G.intraradices ,respectively (Fig.5,Table 1).3.3.Abundance and diversity of AMF spores produced in trap culturesThe numbers of AMF spores produced in trap cultures were consistently decreased by tillage in both M.sativa and Z.mays host plants (Fig.6),ranging from 35to 130and from 3to 34per 10g of soil,in no-tilled and tilled soil,respectively.AMF spore number was also affected by trap plant species,while a strong interaction (P <0.001)was found between host plant species and tillage/fertilization treatments.Therefore,distinct statistical analyses were performed for each host plant,which showed that in M.sativa spore production was marginally affected by tillage and fertilization treatments,while in Z.mays tillage signi ﬁcantly decreased sporu-lation (Table 2).Moreover,an interaction between fertilization and tillage was detected (P ¼0.01).The overall sporulation pattern of the different AMF species showed a predominant effect of tillage,compared with that of host and fertilization treatments,as revealed by CCA (P ¼0.032).The ﬁrst canonical axis explained 95.9%of the cumulative variance ofPCR e DGGE banding patterns data,and the second one explained the remaining 4.1%(Fig.7).F.mosseae was the predominant species sporulating in tilled soils,while G.viscosum and G.intraradices prevailed in no-tilled soils (Fig.8).Interestingly,G.intraradices spores were not retrieved from all tilled treatments.A low number of Funneliformis geosporus spores (T.H.Nicolson &Gerd.)C.Walker &A.Schüssler was retrieved only from M.sativa traps (Fig.8).With M.sativa as host plant,the number of G.viscosum spores was signi ﬁcantly lower in trap cultures from tilled than from no-tilled soils (P ¼0.01),while F.mosseae spore number signi ﬁcantly decreased in fertilized soil (P ¼0.001).With Z.mays as host plant,only G.viscosum spore number was signi ﬁcantly affected by fertilization treatments (P ¼0.011),with a strong fertilization by tillage interaction (P ¼0.002),as a result of its high sporulation in fertilized and NT plots.3.4.GRSP content in ﬁeld soil and in trap culturesBoth T-and EE-GRSP concentrations were larger in no-tilled than in tilled ﬁeld soil,and correlated well each other (Pearson correlation ¼0.823;P <0.001).T-GRSP content was signi ﬁcantly affected by tillage (P ¼0.023),and was about 36.1%larger in NT than in CT plots (Fig.9).On the other hand,fertilization did not affect GRSP content (P ¼0.132and 0.082,respectively for T-GRSP and EE-GRSP).No differences in GRSP content of trap culture soil were found.4.Discussion4.1.PCR e DGGE pattern analysis of AM fungal diversity in ﬁeld soil and trap culturesCCA of PCR e DGGE pro ﬁles clearly showed that AMF commu-nities were affected by N-fertilization both in ﬁeld soil and in roots and soil of M.sativa trap plants.Such ﬁndings are in agreement with a previous DGGE-based study showing differences in the community composition of AMF colonizing the roots of Festuca pratensis and Achillea millefolium in a Swedish grazed grassland along a gradient of soil N and P concentration (Santos et al.,2006).Other studies,performed on AMF spores,indirectly evidenced that AMF may be affected by the use of chemical fertilizers:for example Oehl et al.(2004)showed that organic farming,where the use of chemical fertilizers is not allowed,promoted higher AMF diversity and abundance than conventional agriculture,whilst other authors found a lower AMF diversity and abundance in N fertilised agro-ecosystems (Egerton-Warburton and Allen,2000).CCA of PCR e DGGE pro ﬁles further displayed an impact of tillage on AMF communities,supporting recent data obtained in long-term experiments in temperate regions (Mirás-Avalos et al.,2011;Mathew et al.,2012).Actually in our study the occurrence of weeds as a consequence of no-tillage and N fertilization (De Sanctis et al.,2012)may have represented a further factor affecting the abundance and diversity of AMF.However,the effects of tillage treatments on AMF communities observed in ﬁeld soil were con ﬁrmed by CCA of PCR e DGGE pro ﬁles from roots and soil of M.sativa and Z.mays trap plants.In this work,CCA evidenced an effect of M.sativa and Z.mays trap plants on AMF soil communities and a major effect of N-fertilization on AMF occurring in the soil and in the roots of M.sativa plants,suggesting that the responses of AMF to different agronomical treatments may depend also by host plant taxon or its nutritional status (Giovannetti et al.,1988;Egerton-Warburton and Allen,2000).Indeed,Oliveira et al.(2009)showed that tropical maize genotypes contrasting for phosphorus ef ﬁciency had a greater in ﬂuence on AMF rhizosphere community than the level of P in the soil.Table 1Nuclear SSU rDNA sequence types obtained from clones of DGGE excised bands of Medicago sativa and Zea mays roots and spores of AMF produced in trap cultures.Sequence types Identity (%)Taxonomic af ﬁliation Ag1NG017178(100)Funneliformis mosseae Ag2AJ505813(99)Glomus viscosum Ag3AJ536822(99)Glomus intraradices Ag4GU353916(99)Uncultured Glomus sp.Ag5GU353731(99)Uncultured Glomus sp.20406080100120140160180NT0MNT90MNT0ZNT90ZCT0MCT90MCT0ZCT90ZS p o r e n u m b e r 10 g s o i lFig.6.Total AMF spore density in trap cultures from conventionally tilled (CT)and no tilled (NT)plots fertilized with 0(NT0,CT0)or 90(NT90,CT90)kg ha À1N,and with Medicago sativa (M)or Zea mays (Z)as trap plant,after sixteen months ’growth.Error bars refer to standard error of the means (n ¼2).L.Avio et al./Soil Biology &Biochemistry 67(2013)285e 294290。

深松和秸秆还田对灌耕灰钙土土壤细菌多样性和群落结构的影响

Effects of subsoiling and the return of straw on soil bacterial diversity and community structure in anirrigated sierozem farmlandWEN Meijuan,YANG Sicun *,WANG Chengbao,HUO Lin（Institute of Soil Fertilizer and Water-saving Agriculture,Gansu Academy of Agriculture Sciences,Lanzhou 730070,China ）Abstract ：A field experiment was conducted to study the effect of 35cm subsoiling with the return of maize straw （STS ）,35cm subsoiling （ST ）,and conventional rotary tillage （RT ）on the soil properties,soil bacterial diversity,and the community structure at a depth of 0–20cm on irrigated sierozem in the Gansu Yellow River irrigated area in 2015—2020.Results showed that,compared with RT and ST,STS could promote soil fertility,increase bacterial OTU numbers and the bacterial Alpha diversity.The distribution characteristics of the soil bacterialcommunities were significantly different.The soil pH,organic carbon （SOC ）,water content （SWC ）,cation exchange capacity （CEC ）,total nitrogen （TN ）,and alkali-hydrolyzable nitrogen （AHN ）had significant or extremely significant correlations with bacterial α-diversity.Proteobacteria,Acidobacteria,Bacteroidetes,Actinobacteria and Chloroflexi were the dominant bacterial abundant in soil under different treatments at the phyla level,compared with ST and RT.STS could significantly increase the relative abundance of Proteobacteria and深松和秸秆还田对灌耕灰钙土土壤细菌多样性和群落结构的影响温美娟，杨思存*，王成宝，霍琳（甘肃省农业科学院土壤肥料与节水农业研究所，兰州730070）收稿日期：2022-04-18录用日期：2022-06-01作者简介：温美娟（1988—），女，甘肃天水人，助理研究员，主要从事土壤耕作与土壤环境的研究。

雅思-IELTS-剑9-测试二-reading-1

剑桥雅思9 测试二Reading Passage 1You should spend about 20 minutes on Question 1-13 which are based on Reading Passage 1 below.AHearing impairment or other auditory function deficit in young children can have a major impact on their development of speech and communication, resulting in a detrimental effect on their ability to learn at school. This is likely to have major consequences for the individual and the population as a whole. The New Zealand Ministry of Health has found from research carried out over two decades that 6-19% of children in that country are affected by hearing loss.BA preliminary study in New Zealand has shown that classroom noise presents a major concern for teachers and pupils. Modern teaching practices, the organization of desks in the classroom, poor classroom acoustics, and mechanical means of ventilation such as air-conditioning units all contribute to the number of children unable to comprehend the teacher’s voice. Education researchers Nelson and Soli have also suggested that recent trends in learning often involve collaborative interaction of multiple minds and tools as much as individual possession of information. This all amounts to heightened activity and noise levels, which have the potential to be particularly serious for children experiencing auditory function deficit. Noise in classrooms can only exacerbate their difficulty in comprehending and processing verbal communication with other children and instructions from the teacher.CChildren with auditory function deficit are potentially failing to learn to their maximum potential because of noise levels generated in classrooms. The effects of noise on the ability of children to learn effectively in typical classroom environments are now the subject of increasing concern. The International Institute of Noise Control Engineering (I-INCE), on the advice of the World Health Organization, has established an international working party, which includes New Zealand, to evaluate noise and reverberation control for school rooms.While the detrimental effects of noise in classroom situations are not limited to children experiencing disability, those with a disability that affects their processing of speech and verbal communication could be extremely vulnerable. The auditory function deficits in question include hearing impairment, autistic spectrum disorders (ASD) and attention deficit disorders (ADD/ADHD).DAutism is considered a neurological and genetic life-long disorder that causes discrepancies in the way information is processed. This disorder is characterized by interlinking problems with social imagination, social communication and social interaction. According to Janzen, this affects the ability to understand and relate in typical ways to people, understand events and objects in the environment, and understand or respond to sensory stimuli. Autism does not allow learning or thinking in the same ways as in children who are developing normally. Autistic spectrum disorders often result in major difficulties in comprehending verbal information and speech processing. Those experiencing these disorders often find sounds such as crowd noise and the noise generated by machinery painful and distressing. This is difficult to scientifically quantify as such extra-sensory stimuli vary greatly from one autistic individual to another. But a child who finds any type of noise in their classroom or learning space intrusive is likely to be adversely affected in their ability to process information.EThe attention deficit disorders are indicative of neurological and genetic disorders and are characterized by difficulties with sustain ing attention, effort and persistence, organization skills and disinhibition. Children experiencing these disorders find it difficult to screen out unimportant information, and focus on everything in the environment rather than attending to a single activity. Background noise in the classroom becomes a major distraction, which can affect their ability to concentrate.FChildren experiencing an auditory function deficit can often find speech and communication very difficult to isolate and process when set against high levels of background noise. These levels come from outside activities that penetrate the classroom structure, from teaching activities, and other noise generated inside, which can be exacerbated by roomreverberation. Strategies are needed to obtain the optimum classroom construction and perhaps a change in classroom culture and methods of teaching. In particular, the effects of noisy classrooms and activities on those experiencing disabilities in the form of auditory function deficit need thorough investigation. It is probable that many undiagnosed children exist in the education system with‘invisible’ disabilities. Their needs are less likely to be met than those of children with known disabilities.GThe New Zealand Government has developed a New Zealand Disability Strategy and has embarked on a wide-ranging consultation process. The strategy recognizes that people experiencing disability face significant barriers in achieving a full quality of life in areas such as attitude, education, employment and access to services. Objective 3 of the New Zealand Disability Strategy is to ‘Provide the Best Education for Disabled People’ by improving education so that all ch ildren, youth learners and adult learners will have equal opportunities to learn and develop within their already existing local school. For a successful education, the learning environment is vitally significant, so any effort to improve this is likely to be of great benefit to all children, but especially to those with auditory function disabilities.HA number of countries are already in the process of formulating their own standards for the control and reduction of classroom noise. New Zealand will probably follow their example. The literature to date on noise in school rooms appears to focus on the effects on schoolchildren in general, their teachers and the hearing impaired. Only limited attention appears to have been given to those students experiencing the other disabilities involving auditory function deficit. It is imperative that the needs of these children are taken into account in the setting of appropriate international standards to be promulgated in future.生词查了一遍Aimpairment名：损伤，损害auditory听觉的，听觉器官的。

不同施肥处理对幼龄果林套种大豆生长的影响

收稿日期:2023-03-27基金项目:内蒙古科技创新引导奖励资金项目高产㊁高油㊁广适大豆新品种赤豆5号示范与推广 (赤财指科[2021]757号)㊂作者简介:魏云山(1978 ),男,内蒙古赤峰人;硕士,研究员,主要从事作物育种与高产栽培技术研究(E -m a i l :41396001@q q.c o m )㊂不同施肥处理对幼龄果林套种大豆生长的影响魏云山, 刘迎春, 胡海波, 康泽然, 崔智慧(赤峰市农牧科学研究所, 内蒙古赤峰024031)摘要:为探讨不同施肥处理对1~3年幼龄果林套种大豆生长的影响,研究分析了不同施肥处理对幼果林内赤豆5号的植株性状㊁产量性状的影响㊂结果表明,与不施肥处理相比,不同施肥处理显著提高了幼龄果林内套种大豆的综合性状和产量,产量顺序为常规肥+叶面肥>常规肥>c k ㊂其中,常规肥+叶面肥处理产量为1853.60k g/h m 2,比对照增产259.90k g /h m 2,增产率为16.3%,综合性状表现较好㊂关键词: 幼龄果林;套种;大豆;施肥中图分类号: S 565.1 文献标志码: A 文章编号: 1008-2239(2023)04-0039-02E f f e c t s o fD i f f e r e n tF e r t i l i z a t i o nT r e a t m e n t s o n t h eG r o w t ho f I n t e r p l a n t e dS o yb e a n W E IY u n s h a n ,L I UY i n gc h u n ,H U H a i b o ,K A N GZ e r a n ,C U IZ h i h u i (C h i f e n g A c ade m y o fA g r i c u l t u r a l a n dA n i m a lH u s b a n d r y Sc i e n c e s ,C h i f e n g I n n e r M o n go l i a 024031,C h i n a )A b s t r a c t :I no r d e r t o s t u d y t h e e f f e c t o f d i f f e r e n t f e r t i l i z a t i o n t r e a t m e n t s o n t h e g r o w t h o f i n t e r p l a n t i n gs o y b e a n i n1-3y e a r s y o u n g fr u i t f o r e s t ,t h ee f f e c to fd i f f e r e n t f e r t i l i z a t i o nt r e a t m e n t so nt h e p l a n t c h a r a c t e r ,y i e l d c h a r a c t e r a n d y i e l do fC h i d o u 5i n y o u n g fr u i t f o r e s tw a s s t u d i e d .T h e r e s u l t s s h o w e d t h a t c o m p a r e dw i t hn o n -f e r t i l i z a t i o n ,d i f f e r e n t f e r t i l i z a t i o n t r e a t m e n t s i g n i f i c a n t l y i m p r o v e d t h e c o m -p r e h e n s i v e c h a r a c t e r s a n d y i e l do f i n t e r p l a n t e d s o y b e a n i n y o u n g fr u i t f o r e s t ,a n d t h e y i e l do r d e rw a s c o n v e n t i o n a f e r t i l i z e r +f o l i a r f e r t i l i z e r >c o n v e n t i o n a l f e r t i l i z e r >c k .T h e y i e l d o f c o n v e n t i o n a l f e r t i l i z e r +f o l i a rf e r t i l i z e rw a s 1853.60kg /h m 2,w hi c hw a s 259.90k g /h m 2a n d 16.3%h i g h e r t h a n c k ,t h e c o m p r e h e n -s i v e c h a r a c t e r sw e r eb e t t e r .K e y wo r d s : y o u n g f r u i t f o r e s t ;i n t e r p l a n t i n g ;s o y b e a n ;f e r t i l i z a t i o n 近几年,随着大豆产业振兴政策的提出,大豆种植面积有所回升[1]㊂由于我国大豆单种产量低,效益不高,果树幼林普遍行距宽广,果实初期树冠较小,存在较大的空间,在果树幼林中套种大豆是提高大豆种植面积的有效途径[2]㊂幼龄果树套种大豆,不但可以增加土地的利用率,而且还能抑制杂草,多收一茬豆,是赤峰市果农的主要种植方式[3]㊂本试验在赤峰地区开展果树幼林套种大豆施肥试验,探索果树幼林套种大豆最佳施肥量,为果树幼林套种大豆提供数据支持㊂1 材料与方法1.1 试验地概况试验在赤峰市松山区古都河1~3年幼龄果园内进行㊂土壤类型为沙壤土,试验地土质疏松㊁水源充足㊂1.2 试验材料试验材料为赤峰市农牧科学研究所自主选育的大豆新品种赤豆5号㊂试验肥料为硫包衣尿素(N ,32%)㊁磷酸二铵(P 2O 546%,N18%)㊁硫酸钾(K 2O ,52%)㊂1.3 试验设计每两行幼龄果树间套种4m 大豆㊂随机区组排㊃93㊃耕作与栽培,2023,43(4):38-40. h t t p ://g z z p .g z n y z y x y .c n T i l l a g e a n dC u l t i v a t i o n V o l .43 N o .04 A u g. 2023列,3次重复,小区行长5m ,8行区,小区面积20m 2㊂设置3个不同施肥处理,常规施肥:控释尿素75k g/h m 2+磷酸二铵150k g /h m 2+硫酸钾75k g/h m 2;常规肥+叶面肥:控释尿素75k g /h m 2+磷酸二铵150k g /h m 2+硫酸钾75k g/h m 2,花期追施2%尿素2次;c k :不施任何肥料㊂间苗㊁定苗时留整齐一致的植株,田间管理同大田管理一致,成熟期在各小区随机选取大豆植株5株进行考种,分别测定株高㊁主茎节数㊁主茎分枝数㊁单株粒数㊁单株粒重㊁百粒重等指标,收整区测产㊂2 结果与分析2.1 不同施肥处理对套种大豆盛花期植株性状的影响由表1可知,在花期,果林内不同处理的套种大豆株高㊁根长㊁地上干重㊁地下干重性状差异均不显著㊂其中,常规肥和常规肥+叶面肥处理株高分别比对照增加1.3c m ㊁2.3c m ,增幅为4.2%,7.4%;根长分别比对照增加2.8c m ㊁2.2c m ,增幅为13.1%,10.3%;地上干重分别比对照增加0.14g ㊁0.6g ,增幅为0.8%,3.6%;地下干重分别比对照增加0.13g ㊁0.22g ,增幅为6.5%,10.9%㊂表1 不同施肥处理对套种大豆盛花期植株性状的影响处理株高/c m根长/c m地上干重/(g/株)地下干重/(g/株)常规肥32.3a24.1a16.67a 2.14a 常规肥+叶面肥33.3a 23.5a 17.13a 2.23a 不施肥(c k)31.0a 21.3a 16.53a 2.01a 2.2 不同施肥处理对套种大豆成熟期植株性状的影响由表2可知,在成熟期,果林内不同处理的套种大豆地上干重㊁地下干重差异显著,株高㊁根长差异不显著㊂其中,常规肥和常规肥+叶面肥处理根长分别比对照增加1.6c m ㊁2.8c m ,增幅为6.9%,12.1%;地上干重分别比对照增加1.94g ㊁8.04g ,增幅为6.4%,26.4%;地下干重分别比对照增加0.10g ㊁0.29g ,增幅为4.2%,12.3%;常规肥+叶面肥处理株高比对照增加2.5c m ,增幅为3.9%㊂表2 不同施肥处理对套种大豆成熟期植株性状的影响处理株高/c m根长/c m地上干重/(g /株)地下干重/(g /株)常规肥63.5a24.8a35.37b2.46a b常规肥+叶面肥66.1a26.0a38.47a 2.65a 不施肥(c k)63.6a 23.2a 30.43c2.36b2.3 不同施肥处理对套种大豆产量性状的影响从表3可以看出,果林内不同处理套种大豆间主茎分枝数㊁单株荚数㊁单数粒数㊁单株粒重存在显著性差异,主茎节数和百粒重差异均不显著㊂其中,常规肥和常规肥+叶面肥处理主茎分枝数均比对照提高了0.1个,增幅为100%;单株荚数比对照分别提高了3.4个㊁4.6个,增幅为12.7%和17.2%;单株粒数比对照分别提高了2.4个㊁4.1个,增幅为4.6%和7.8%;单株粒重比对照分别提高了0.28g ㊁1.34g ,增幅为3.1%和14.9%;主茎节数比对照分别提高了0.7个㊁1.0个,增幅为5.4%和7.7%;百粒重比对照分别提高了1.27g ㊁0.62g ,增幅为6.4%和3.1%㊂表3 不同施肥处理对套种大豆产量性状的影响处理主茎节数/个主茎分枝数/个单株荚数/个单株粒数/粒单株粒重/g百粒重/g常规肥13.7a 0.2a 30.2a 55.1a 9.28b 21.08a 常规肥+叶面肥14.0a 0.2a 31.4a 56.8a 10.34a 20.43a 不施肥(c k)13.0a 0.1b 26.8b 52.7b 9.00c 19.81a 2.4 不同施肥处理对套种大豆产量的影响从表4可以看出,果林内不同处理显著提高了套种大豆的产量㊂产量顺序为常规肥+叶面肥>常规肥>c k ,常规肥+叶面肥处理产量最高,比对照增产259.90k g/h m 2,增产率为16.3%,其次是常规肥处理,比对照增产153.25k g/h m 2,增产率为9.6%㊂常规肥和常规肥+叶面肥处理间差异不显著㊂表4 不同施肥处理对套种大豆产量的影响处理产量/(k g/h m 2)ⅠⅡⅢ平均产量/(k g/h m 2)常规肥1744.351788.451708.051746.95a常规肥+叶面肥1844.701939.801776.301853.60a 不施肥(c k)1638.901548.601593.601593.70b3 结论不同施肥处理显著提高了幼龄果林内套种大豆的综合性状和产量㊂产量顺序为常规肥+叶面肥>常规肥>c k ,常规肥和常规肥+叶面肥处理间差异不显著,生产上均可推荐施用,常规肥+叶面肥处理产量最高,比对照增产259.90k g /h m 2,增产率为16.3%㊂参考文献:[1]孙磊.新时代背景下发展中国大豆科技和振兴大豆产业策略分析[J ].大豆科技,2020(4):20-23,31.[2]韦瑞敏,黄凤团.幼龄果树园套种大豆栽培技术[J ].科学种养,2013(2):16.[3]王艮龙,顾斌.果园行间套种药材技术研究[J ].林业科技情报,2016,48(2):12-15.㊃04㊃魏云山等:不同施肥处理对幼龄果林套种大豆生长的影响耕作与栽培第43卷第4期。

雅思IELTS剑9测试二reading1

雅思IELTS剑9测试二reading1剑桥雅思9 测试二Reading Passage 1You should spend about 20 minutes on Question 1-13 which are based on Reading Passage 1 below.AHearing impairment or other auditory function deficit in young children can have a major impact on their development of speech and communication, resulting in a detrimental effect on their ability to learn at school. This is likely to have major consequences for the individual and the population as a whole. The New Zealand Ministry of Health has found from research carried out over two decades that 6-19% of children in that country are affected by hearing loss.BA preliminary study in New Zealand has shown that classroom noise presents a major concern for teachers and pupils. Modern teaching practices, the organization of desks in the classroom, poor classroom acoustics, and mechanical means of ventilation such as air-conditioning units all contribute to the number of children unable to compre hend the teacher’s voice. Education researchers Nelson and Soli have also suggested that recent trends in learning often involve collaborative interaction of multiple minds and tools as much as individual possession of information. This all amounts to heightened activity and noise levels, which have the potential to be particularly serious for children experiencing auditory function deficit. Noise in classrooms can only exacerbate their difficulty in comprehending and processing verbal communication with other children andinstructions from the teacher.CChildren with auditory function deficit are potentially failing to learn to their maximum potential because of noise levels generated in classrooms. The effects of noise on the ability of children to learn effectively in typical classroom environments are now the subject of increasing concern. The International Institute of Noise Control Engineering (I-INCE), on the advice of the World Health Organization, has established an international working party, which includes New Zealand, to evaluate noise and reverberation control for school rooms.While the detrimental effects of noise in classroom situations are not limited to children experiencing disability, those with a disability that affects their processing of speech and verbal communication could be extremely vulnerable. The auditory function deficits in question include hearing impairment, autistic spectrum disorders (ASD) and attention deficit disorders (ADD/ADHD).DAutism is considered a neurological and genetic life-long disorder that causes discrepancies in the way information is processed. This disorder is characterized by interlinking problems with social imagination, social communication and social interaction. According to Janzen, this affects the ability to understand and relate in typical ways to people, understand events and objects in the environment, and understand or respond to sensory stimuli. Autism does not allow learning or thinking in the same ways as in children who are developing normally. Autistic spectrum disorders often result in major difficulties in comprehending verbal information and speechprocessing. Those experiencing these disorders often find sounds such as crowd noise and the noise generated by machinery painful and distressing. This is difficult to scientifically quantify as such extra-sensory stimuli vary greatly from one autistic individual to another. But a child who finds any type of noise in their classroom or learning space intrusive is likely to be adversely affected in their ability to process information.EThe attention deficit disorders are indicative of neurological and genetic disorders and are characterized by difficulties with sustain ing attention, effort and persistence, organization skills and disinhibition. Children experiencing these disorders find it difficult to screen out unimportant information, and focus on everything in the environment rather than attending to a single activity. Background noise in the classroom becomes a major distraction, which can affect their ability to concentrate.FChildren experiencing an auditory function deficit can often find speech and communication very difficult to isolate and process when set against high levels of background noise. These levels come from outside activities that penetrate the classroom structure, from teaching activities, and other noise generated inside, which can be exacerbated by roomreverberation. Strategies are needed to obtain the optimum classroom construction and perhaps a change in classroom culture and methods of teaching. In particular, the effects of noisy classrooms and activities on those experiencing disabilities in the form of auditory function deficit need thorough investigation. It is probable that many undiagnosed children exist in the e ducation system with‘invisible’ disabilities. Their needs areless likely to be met than those of children with known disabilities.GThe New Zealand Government has developed a New Zealand Disability Strategy and has embarked on a wide-ranging consultation process. The strategy recognizes that people experiencing disability face significant barriers in achieving a full quality of life in areas such as attitude, education, employment and access to services. Objective 3 of the New Zealand Disability Strategy is to ‘Provide the Best Education for Disabled People’ by improving education so that all ch ildren, youth learners and adult learners will have equal opportunities to learn and develop within their already existing local school. For a successful education, the learning environment is vitally significant, so any effort to improve this is likely to be of great benefit to all children, but especially to those with auditory function disabilities.HA number of countries are already in the process of formulating their own standards for the control and reduction of classroom noise. New Zealand will probably follow their example. The literature to date on noise in school rooms appears to focus on the effects on schoolchildren in general, their teachers and the hearing impaired. Only limited attention appears to have been given to those students experiencing the other disabilities involving auditory function deficit. It is imperative that the needs of these children are taken into account in the setting of appropriate international standards to be promulgated in future.生词查了一遍Aimpairment名：损伤，损害auditory听觉的，听觉器官的。

小学上册U卷英语第四单元期末试卷

小学上册英语第四单元期末试卷英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.The ________ is a friend to all who visit.2.What is the capital of India?A. MumbaiB. DelhiC. KolkataD. Chennai3.What do we call the sport played on ice?A. HockeyB. FootballC. BasketballD. Baseball4.I have a _____ (手电筒) for camping trips at night. 我有一个晚上露营时用的手电筒。

5.We can ___ the ocean. (explore)6.The sun is _____ (shining/raining) bright today.7.What is the term for the distance light travels in one year?A. Light-YearB. Astronomical UnitC. ParsecsD. Cosmic Yard8. A chemical equation must be balanced to comply with the law of ______.9.What do we call the study of the classification of organisms?A. TaxonomyB. EcologyC. BiologyD. Genetics10. A _______ (小海龟) lays eggs on the beach.11.The ______ is a talented artist.12.The crab scuttles sideways on the _______ (沙滩).13.I love the sound my __________ (玩具名) makes when I __________ (动词).14.What is the name of the famous Italian city known for its canals?A. FlorenceB. VeniceC. RomeD. MilanB15.He loves to watch ________ movies.16.The bird is ________ in the tree.17.The speed of sound is faster than the speed of ______.18.My brother is a ______. He enjoys woodworking.19.We participate in ________ (projects) for school.20.What is the capital city of Nigeria?A. AbujaB. LagosC. KanoD. Port HarcourtA21.Hawaii is an example of a __________.22.The __________ (工厂制度) started during the Industrial Revolution.23.The process of sublimation occurs from solid directly to ______.24. A __________ is formed by the action of glaciers on rock surfaces.25.The __________ is a region known for its hot climate.26.What do we call the time it takes for the Earth to go around the sun?A. MonthB. DayC. YearD. Hour27.We have _______ for breakfast.28.I enjoy _______ (和朋友一起玩).29.What is the name of the famous mouse created by Walt Disney?A. Donald DuckB. Bugs BunnyC. Mickey MouseD. GoofyC30.My dad enjoys going to the ____ (beach).31.I enjoy ________ at the beach.32.My friend loves to __________ (写作).33.Which planet is known as the blue planet?A. MarsB. EarthC. NeptuneD. UranusB34.The porcupine has sharp ________________ (刺).35.The ____ makes a great pet and loves to play fetch.36.What is the name of the famous scientist who developed the laws of motion?A. Albert EinsteinB. Isaac NewtonC. Charles DarwinD. Louis PasteurB37.I visit my ______ on weekends. (grandparents)38.The spider spins a _______ (蜘蛛织了一个_______).39.Which fruit is yellow and curved?A. AppleB. BananaC. OrangeD. GrapeB40.All matter is made up of _____.41.My sister is very __________ (细心的) with her work.42. A cute ___ (小狗) is barking in the park.43.What do we call the act of reading a book aloud?A. RecitingB. NarratingC. SpeakingD. ReadingD44.Astronomical phenomena can be observed with the naked _______.45.The __________ is a critical area for biodiversity.46.We visit ______ (艺术馆) to see paintings.47. A __________ is a large area of land that is flat or gently rolling.48. A _______ is a substance that can change the rate of a chemical reaction. (催化剂)49.Which of these is a vegetable?A. AppleB. CarrotC. BananaD. Grape50.I love _____ (reading/playing) books.51.Stars live for millions of ______.52.The sun is ______ (shining) on the water.53.My best friend is my _______ because we share dreams.54.The __________ (历史的多重解读) enriches narratives.55.The __________ can change due to human intervention.56.What do you call a place where you can buy food and drinks?A. MarketB. RestaurantC. Grocery storeD. All of the aboveD57.Chemical reactions often involve the rearrangement of _____.58.What is the hardest natural substance?A. GoldB. DiamondC. IronD. SilverB59.The cake is ___ (decorated) for the party.60.The ancient Romans had a complex belief in ________.61.He can _____ a bicycle. (ride)62. A ________ (植物遗传学研究) sheds light on evolution.63.What do you call a house made of ice?A. CabinB. IglooC. CottageD. BungalowB64.The rabbit loves to hop around the _________. (院子)65.The ostrich lays the largest _______ (鸟蛋).66.I like to ________ (散步) after dinner.67.Matter is anything that has ________ and takes up space.68.The author writes _____ (小说) about adventure.69.The porpoise is related to the _______ (海豚).70. Age is characterized by the use of ______ (石头) tools. The Ston71.I enjoy collecting ______ (邮票) from different countries.72.I want to _______ a book about animals.73.In _____ (印度), the monsoon season brings heavy rains.74.I want to be a ________ when I grow up.75.The ancient Greeks used _____ to teach moral lessons.76.__________ (化学问题) arise from practical applications and theoretical concepts.77.The teacher is _____ the students to listen. (asking)78.What is the main ingredient in chocolate?A. SugarB. Cocoa BeansC. FlourD. Milk79.The ______ is very inspiring.80._____ (蝴蝶) love to visit colorful flowers.81.The chemical symbol for rhodium is ______.82.What is the name of the famous American singer known for "Billie Jean"?A. Michael JacksonB. PrinceC. UsherD. Justin TimberlakeA83.My sister is learning to play the __________ (乐器).84.The ________ (生态系统恢复) is ongoing.85.The __________ can help us understand past geological events.86.What color are strawberries?A. BlueB. YellowC. RedD. Green87.What do you call a person who plays an instrument?A. SingerB. DancerC. MusicianD. Painter88.The ________ (农田) produces lots of food.89.At the zoo, I saw a playful ________ (猴子) swinging from tree to tree. It made me ________ (笑).90.My sister loves to create ____ (art projects).91. A reaction that releases energy is called an ______ reaction.92.I love the scent of fresh __________ (花卉).93.I like to watch the ______ (风筝) fly.94.The kitten is _____ (cute/ugly).95.I can ______ (跳) high on the trampoline.96.What is the capital of the Falkland Islands?A. StanleyB. Port StanleyC. Goose GreenD. DarwinA97.What is the largest mammal in the world?A. ElephantB. Blue whaleC. GiraffeD. Hippo98.I enjoy planting _____ in my garden.99.We use ______ (肥料) to help plants grow.100.They are __________ to the store.。

洛阳2024年10版小学5年级上册第3次英语第3单元期末试卷[含答案]

洛阳2024年10版小学5年级上册英语第3单元期末试卷[含答案]考试时间：100分钟（总分:110）B卷考试人：_________题号一二三四五总分得分一、综合题(共计100题)1、What is the largest planet in our solar system?A. EarthB. MarsC. JupiterD. Saturn答案:C2、填空题：I like to go ______ (远足) in the mountains.3、听力题：He is wearing a ___. (hat)4、听力题：I like to ________ with my family.5、What do we call the sound a dog makes?A. MeowB. BarkC. RoarD. Whistle答案:B6、听力题：The Earth's layers are composed of different ______ materials.7、听力题：A chemical change alters the _____ of a substance.8、Which of these is a fruit?A. SpinachB. TomatoC. PotatoD. Carrot答案:B9、听力题：The ______ is famous for her contributions to music.10、填空题：The goldfish has gills to help it _______ (呼吸).11、选择题：Which of these is a type of music?A. JazzB. PaintC. DanceD. Draw12、听力题：The stars twinkle in the ______ (night) sky.13、选择题：What is the main ingredient in mayonnaise?A. MustardB. OilC. EggD. Vinegar14、填空题：Certain plants can grow in ______ (贫瘠的) soil.15、填空题：The _______ (The Harlem Renaissance) was a cultural movement celebrating African American culture.16、填空题：I can create art with my ________ (玩具名称).17、听力题：The ancient Greeks developed the concept of ________.18、填空题：This fruit is very _______ (甜).19、听力题：The main ingredient in bleach is ______.Bees help __________ (授粉) the flowers.21、填空题：I feel _______ when I read.22、填空题：I enjoy singing ______ songs.23、听力题：The chemical symbol for iron is _______.24、听力题：The park is ______ (near) my house.25、填空题：I built a fort using my ________ (玩具名称).26、听力题：My brother is very ________.27、填空题：My mom gives me __________ (建议) when I need help.28、填空题：The __________ (历史的启迪) can motivate change.29、听力题：The cake is on the ___ (table/counter).30、填空题：A __________ (化学工具) aids in conducting precise experiments.31、填空题：The __________ (历史的回音) can still be heard today.32、填空题：My ________ (玩具名称) is a magical creature.33、What is the capital of El Salvador?A. San SalvadorB. Santa AnaC. San MiguelD. La Libertad答案:AI like to collect ________ (邮票) from different places.35、听力题：I want to ______ how to bake cookies. (learn)36、填空题：The __________ (历史的契机) can lead to breakthroughs.37、听力题：A __________ is the point at which an earthquake is felt.38、glacial retreat) shows climate change effects. 填空题：The ____39、填空题：We learn about animals in ______ (科学) class.40、听力题：The Great Wall of China is found in ________.41、听力题：The _______ of matter refers to whether it is a solid, liquid, or gas.42、听力题：Ancient Egyptians built _______ to honor their pharaohs.43、听力填空题：I think kindness is essential in our daily lives. Simple acts of kindness can brighten someone’s day. I try to spread kindness by __________ whenever I can.44、选择题：Which food is made from milk?A. BreadB. CheeseC. RiceD. Vegetables45、听力题：The capital of Egypt is __________.46、填空题：A ______ (蜥蜴) can be found in warm climates.47、听力题：She has a big _____ (狗).48、What is the name of the famous detective created by Arthur Conan Doyle?A. Hercule PoirotB. Sherlock HolmesC. Miss MarpleD. Philip Marlowe答案:B49、What is the main ingredient in hummus?A. ChickpeasB. LentilsC. BeansD. Peas50、听力题：A turtle can hide in its ______ for protection.51、选择题：What is the main ingredient in hummus?A. ChickpeasB. LentilsC. BeansD. Peas52、What is the name of the famous American holiday celebrated on the last Thursday in November?A. ThanksgivingB. ChristmasC. EasterD. Independence Day答案：A53、听力题：The chemical formula for potassium hydrogen phthalate is _______.54、填空题：I created a scavenger hunt with my _________ (玩具).55、In which season does it typically snow?A. SpringB. SummerC. AutumnD. Winter答案:D56、What do plants need to make food?A. WaterB. SoilC. SunlightD. All of the above答案:D57、How many continents are there?a. Fiveb. Sixc. Sevend. Eight答案:C58、听力题：He is very ___. (funny)59、听力题：The tree is _______ (covered) in snow.60、填空题：I have a toy _______ that can climb stairs.61、听力题：The cockatoo has a fluffy _____ crest.62、听力题：The __________ can reveal the effects of human activities on natural systems.63、填空题：My favorite fruit is ________ (桃子) in the summer.64、填空题：My _____ (海豚) jumps out of the water.65、填空题：A ____(sustainable fisheries management) preserves fish populations.66、听力题：I like to listen to ___. (music)67、听力题：We will have a ______ at school tomorrow. (field trip)68、填空题：__________ (混合物) can be separated into its components.A ______ is a visual representation of chemical relationships.70、What is the capital of the United Arab Emirates?A. DubaiB. Abu DhabiC. SharjahD. Ajman71、填空题：My uncle teaches me about . (我叔叔教我关于。

studyproblems5

(1) Show straight lines through the origin that K/L is higher for commodity Y than for X in both nations in the absence of trade and that K/L is higher in nation 2 than in nation 1 for both commodities. (20 points)
(3) Draw a similar figure to show factor intensity reversal. (20points)
5. In a 2x3 specific factor model, two commodities, food and computer are produced with labor and land, labor and capital, respectively. Labor is mobile between sectors. Food is the nation’s export commodity and computer is its import commodity. If the price of food rises, who will be better off, workers, or landowners, or capitalists? Why? (15 points)
C.A lower K/L ration is used in the production of X than Y
D.A higher L/K ratio is used in the production of Y than X
(4). When w/r falls, L/K A. Falls in the production of both

剑8T1S4-地理

剑桥雅思8听力下载Test1Section4 本篇真题听力下载地址名师点题剑桥雅思8听力：1. 本段文章的主题是地理讲座的介绍性部分。

开始介绍是基本知识(we’ll begin with some basics)。

begin with... 意为“以...开始”,同时start with也表示同样的意思。

basic 在此为名词,相当于rationale,意为“基础知识,基本原理”,basic 还可作形容词,意为“基础的, 初步的”。

2. we learn a great deal about all the processes that have affected and that continue to affect the earth’s surface(关于影响以及继续影响地球表面的所有过程我们已经学了很多知识)。

a great deal 意为“大量的”。

affect 是动词,意为“影响”,它还表示“(病)侵袭;假装”等意思,如:Her kidneys had become affected.(她的肾脏受到了感染。

)He affected not to see her.(他假装没看见她。

)affect 的名词形式是effect,常用短语有have an effect on/ upon sth.,意为“对......产生影响”。

effect 还可以作动词,不过作动词时它就不是“影响”的意思了,而是“造成, 产生, 招致;达到(目的)”的意思。

3. 在介绍了几种不同的地理学之后要进行小结:studying this subject is important because without geographical knowledge, we would know very little about our surroundings and we wouldn’t be able to indentify all the problems that relate to them. So, by definition, we wouldn’t be in an informed position to work out how to solve any of them(学习地理学很重要,如果没有地理学知识,我们对我们生活的环境就所知甚少,自然也无法发现与环境相关的问题。

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