黄土高原旱地夏季休闲期~(15)N标记硝态氮的去向
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摘要
夏季休闲是黄土高原旱地小麦常见的蓄纳雨水、恢复地力的措施。随着氮肥用量的增加,一季小麦收获后,旱地土壤剖面累积的硝态氮量不断增加,休闲期间降雨量高,残留硝态氮的去向是值得研究的问题。利用~(15)N标记法研究小麦收获后残留肥料氮在黄土高原旱地(陕西长武)夏季休闲期间的去向,即小麦收获后在微区土壤表层(0~15 cm)施入~(15)N标记的硝态氮肥(30 kg hm~(-2)(以纯氮计),约相当于当地小麦一季作物收获后土壤残留肥料氮量),休闲结束后,采集0~200 cm土壤样品,测定了土壤全氮、硝态氮含量及其~(15)N丰度。结果表明,小麦收获(即休闲开始)时0~200 cm土壤剖面硝态氮累积量在205~268 kg hm-2之间(平均244 kg hm~(-2)),累积量较高。夏季休闲期间降水量为157 mm,属欠水年,但休闲结束后,~(15)N标记肥料氮向下迁移已达80 cm土层,下移深度在45~65cm之间,说明,旱地休闲期间硝态氮的淋溶作用不可忽视。夏季休闲结束后,加入的~(15)N标记肥料氮平均损失率为28%,损失机理值得进一步研究。
【Objective】Summer fallow after winter wheat is harvested in dryland on the Loess Plateau is a very common practice to save rain water,and restore soil fertility for the next crop.Nowadays,the content of nitrogen(N)(mainly in nitrate form)in the soil of the dryland as residue of the fertilizer applied to winter wheat is increasing steadily.As summer is the rainy season in this region,whether or not the high rainfall would increase NO_3~--N leaching loss is an important issue deserving further study.The method of adding ~(15)N labeled nitrate after winter wheat is harvested in dryland is one to quantitativelyexplore fate of the residual fertilizer N in the dryland under summer fallow in the Loess Plateau,and hence to provide a scientific basis for managing Nin dryland.【Method】The ~(15)N labeled fertilization micro-plot(Polyvinylchloridecolumn,25 cm diameter and 25 cm long)method was used to study fate of the residual fertilizer N in the dryland under summer fallow in a field experiment,which hadfive tracts of cropland and two N treatments set up with and without N application(0 and 30 kg N hm~(-2)).~(15)N labeled nitrate was mixed with the surface soil(0~15 cm)in the micro-plot at a rate equal to the content of the residual fertilizer N in the field after winter wheat was harvested.At the end of the summer fallow,soil samples throughout the soil profile(0~200 cm)were taken fromthe micro-plots,for analysis the contents of soil total nitrogen,NO_3~--N,and their ~(15)N abundance.【Result】Results show that at the beginning of the summer fallow,the content of NO_3~--N accumulated in the 0~200 cm soil was quite high,ranging between 205 and 268 kg hm~(-2) and averaging 244 kg hm~(-2);At the end of the summer fallow,apparent NO_3~--N accumulation peaks were found in the soil,40~80 cm in depth,and ~(15)N abundance ranged between 0.408% and 0.482% and averaged 0.429%,being the highest in the soil 60 cm in depth,averaged 0.372% in the soil 80 cm in depth,being higher than the background value of ~(15)N abundance in the soil(0.367 ~(15)N atom%),and was 0.369 % in the soil 100 cm in depth,more or less the same as the background value,in Treatments N30 in all the five tracts of cropland.In the five tracts of cropland,~(15)N labeled nitrate abundance was the highest in the 40~60 cm soil layer in the soil profiles(0~100 cm),averaging 2.151%;and the lowest abundance was in the 80~100 cm soil layer,averaging 0.407%,both significantly higher than the background value.Although the rainfall during the summer fallow season was only 157 mm,making it a dry year,it still leached ~(15)N labeled nitrate down to 80 cm in depth,through a 45~65 cm thick soil layer,and even ~(15)N labeled nitrate was found in 100 cm depth.At the end of the fallow,the content of residual N averaged 21.6 kg hm~(-2) or ranged between 20.8 and 22.9 kg hm~(-2) in the 0~100 cm soil profile,accounting for 71.9% of the applied N fertilizer in all the five tracts of cropland.The content of residual labeled N was 4.5 kg hm~(-2),2.9% of which was in the form of NO_3~--N in the 0~20 cm soil layer;Residual fertilizer N was mainly distributed in the 40~60 cm soil layer,and averaged 17.7 kg hm~(-2) in content,accounting for 52.8% of the total N fertilizer applied,in which ~(15)N labeled nitrate content was 6.8 kg hm~(-2).After the summer fallow,the applied ~(15)N labeled N fertilizer was found lost at a rate of 23.8%~30.8%(averaging 28.1%).【Conclusion】Residual fertilizer N accumulated significantly in the 0~200 cm soil layer of the dryland after wheat was harvested,posing a potential risk of leaching.In 2014,though it was a dry year,the effect of rain water leaching NO_3~--N was still quite significant,indicating that the NO_3~--N leaching in the dryland during the summer fallow season should not be ignored and further studies should be done on mechanisms of its leaching loss.
【Objective】Summer fallow after winter wheat is harvested in dryland on the Loess Plateau is a very common practice to save rain water,and restore soil fertility for the next crop.Nowadays,the content of nitrogen(N)(mainly in nitrate form)in the soil of the dryland as residue of the fertilizer applied to winter wheat is increasing steadily.As summer is the rainy season in this region,whether or not the high rainfall would increase NO_3~--N leaching loss is an important issue deserving further study.The method of adding ~(15)N labeled nitrate after winter wheat is harvested in dryland is one to quantitativelyexplore fate of the residual fertilizer N in the dryland under summer fallow in the Loess Plateau,and hence to provide a scientific basis for managing Nin dryland.【Method】The ~(15)N labeled fertilization micro-plot(Polyvinylchloridecolumn,25 cm diameter and 25 cm long)method was used to study fate of the residual fertilizer N in the dryland under summer fallow in a field experiment,which hadfive tracts of cropland and two N treatments set up with and without N application(0 and 30 kg N hm~(-2)).~(15)N labeled nitrate was mixed with the surface soil(0~15 cm)in the micro-plot at a rate equal to the content of the residual fertilizer N in the field after winter wheat was harvested.At the end of the summer fallow,soil samples throughout the soil profile(0~200 cm)were taken fromthe micro-plots,for analysis the contents of soil total nitrogen,NO_3~--N,and their ~(15)N abundance.【Result】Results show that at the beginning of the summer fallow,the content of NO_3~--N accumulated in the 0~200 cm soil was quite high,ranging between 205 and 268 kg hm~(-2) and averaging 244 kg hm~(-2);At the end of the summer fallow,apparent NO_3~--N accumulation peaks were found in the soil,40~80 cm in depth,and ~(15)N abundance ranged between 0.408% and 0.482% and averaged 0.429%,being the highest in the soil 60 cm in depth,averaged 0.372% in the soil 80 cm in depth,being higher than the background value of ~(15)N abundance in the soil(0.367 ~(15)N atom%),and was 0.369 % in the soil 100 cm in depth,more or less the same as the background value,in Treatments N30 in all the five tracts of cropland.In the five tracts of cropland,~(15)N labeled nitrate abundance was the highest in the 40~60 cm soil layer in the soil profiles(0~100 cm),averaging 2.151%;and the lowest abundance was in the 80~100 cm soil layer,averaging 0.407%,both significantly higher than the background value.Although the rainfall during the summer fallow season was only 157 mm,making it a dry year,it still leached ~(15)N labeled nitrate down to 80 cm in depth,through a 45~65 cm thick soil layer,and even ~(15)N labeled nitrate was found in 100 cm depth.At the end of the fallow,the content of residual N averaged 21.6 kg hm~(-2) or ranged between 20.8 and 22.9 kg hm~(-2) in the 0~100 cm soil profile,accounting for 71.9% of the applied N fertilizer in all the five tracts of cropland.The content of residual labeled N was 4.5 kg hm~(-2),2.9% of which was in the form of NO_3~--N in the 0~20 cm soil layer;Residual fertilizer N was mainly distributed in the 40~60 cm soil layer,and averaged 17.7 kg hm~(-2) in content,accounting for 52.8% of the total N fertilizer applied,in which ~(15)N labeled nitrate content was 6.8 kg hm~(-2).After the summer fallow,the applied ~(15)N labeled N fertilizer was found lost at a rate of 23.8%~30.8%(averaging 28.1%).【Conclusion】Residual fertilizer N accumulated significantly in the 0~200 cm soil layer of the dryland after wheat was harvested,posing a potential risk of leaching.In 2014,though it was a dry year,the effect of rain water leaching NO_3~--N was still quite significant,indicating that the NO_3~--N leaching in the dryland during the summer fallow season should not be ignored and further studies should be done on mechanisms of its leaching loss.
引文
[1]高焕文,李问盈,李洪文.中国特色保护性耕作技术.农业工程学报,2003,19(3):1—4Gao H W,Li W Y,Li H W.Conservation tillage technology with Chinese characteristics(In Chinese).Transactions of the Chinese Society of Agricultural Engineering,2003,19(3):1—4
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[4]He G,Wang Z H,Li F C,et al.Soil nitrate-N residue,loss and accumulation affected by soil surface management and precipitation in a winter wheatsummer fallow system on dryland.Nutrient Cycling in Agroecosystems,2016,106(1):31—46
[5]山仑.旱地农业技术发展趋向.中国农业科学,2002,35(7):848—855Shan L.Development trend of dryland farming technologies(In Chinese).Scientia Agricultura Sinica,2002,35(7):848—855
[6]闫湘,金继运,何萍,等.提高肥料利用率技术研究进展.中国农业科学,2008,41(2):450—459Yan X,Jin J Y,He P,et al.Recent advances in technology of increasing fertilizer use efficiency(In Chinese).Scientia Agricultura Sinica,2008,41(2):450—459
[7]王西娜,王朝辉,李华,等.旱地土壤中残留肥料氮的动向及作物有效性.土壤学报,2016,53(5):1202—1212Wang X N,Wang Z H,Li H,et al.Dynamics and availability to crops of residual fertilizer nitrogen in upland soil(In Chinese).Acta Pedologica Sinica,2016,53(5):1202—1212
[8]赵伟,梁斌,周建斌.施入15N标记氮肥在长期不同培肥土壤的残留及其利用.土壤学报,2015,52(3):587—596Zhao W,Liang B,Zhou J B.Residual of applied 15N fertilizer in soilsunder long-term different patterns of fertilization and its utilization(In Chinese).Acta Pedologica Sinica,2015,52(3):587—596
[9]Dai J,Wang Z H.Li F C,et al.Optimizing nitrogen input by balancing winter wheat yield and residual nitrate-N in soil in a long-term dryland field experiment in the Loess Plateau of China.Field Crops Research,2015,181:32—41
[10]Zhou J Y,Gu B J,Schlesinger W H,et al.Significant accumulation of nitrate in Chinese semi-humid croplands.Scientific Reports,2016,6:Article number:25088
[11]Conway G R,Pretty J N.Unwelcome harvest:Agriculture and pollution.London:Earthscan Publications,1991
[12]巨晓棠,谷保静.我国农田氮肥施用现状、问题及趋势.植物营养与肥料学报,2014,20(4):783—795Ju X T,Gu B J.Status-quo,problem and trend of nitrogen fertilization in China(In Chinese).Plant Nutrition and Fertilizer Science,2014,20(4):783—795
[13]Galloway J N,Aber J D,Erisman J W,et al.The nitrogen cascade.Bioscience,2003,53(4):341—356
[14]Wang G L,Chen X P,Cui Z L,et al.Estimated reactive nitrogen losses for intensive maize production in China.Agriculture,Ecosystems&Environment,2014,197:293—300
[15]Kanter D R,Zhang X,Mauzerall D L.Reducing nitrogen pollution while decreasing farmers'costs and increasing fertilizer industry profits.Journal of Environmental Quality,2015,44(2):325—335
[16]彭琳,彭祥林,卢宗藩.塿土旱地土壤硝态氮季节性变化与夏季休闲的培肥增产作用.土壤学报,1981,18(3):211—222Peng L,Peng X L,Lu Z F.NO3--N seasonal change in dryland and fertilization production role during summer fallow of Lou soil(In Chinese).Acta Pedologica Sinica,1981,18(3):211—222
[17]Darwiche-Criado N,Comín F A,Sorando R,et al.Seasonal variability of NO3-mobilization during flood events in a Mediterranean catchment:The influence of intensive agricultural irrigation.Agriculture,Ecosystems&Environment,2015,200:208—218
[18]戴健,王朝辉,李强,等.氮肥用量对旱地冬小麦产量及夏闲期土壤硝态氮变化的影响.土壤学报,2013,50(5):956—965Dai J,Wang Z H,Li Q,et al.Effects of nitrogen application rate on winter wheat yield andsoil nitrate nitrogen during summer fallow season on dryland(In Chinese).Acta Pedologica Sinica,2013,50(5):956—965
[19]Hauck R D,Bremner J M.Use of tracers for soil and fertilizer nitrogen research.Advances in Agronomy,1976,28:219—266
[20]Sebilo M,Mayer B,Grably M,et al.The use of the ammonium diffusion method forδ15N-NH4+andδ15N-NO3-measurements:Comparison with other techniques.Environmental Chemistry,2004,1(2):99—103
[21]Brooks P D,Stark J M,Mc Inteer B B,et al.Diffusion method to prepare soil extracts for automated nitrogen-15 analysis.Soil Science Society of America Journal,1989,53(6):1707—1711
[22]吴义城,袁业畅,任耀武,等.农业气候影响评价:农作物气候年型划分方法(GB/T 21986-2008).北京:中国标准出版社,2008Wu Y C,Yuan Y C,Ren Y W,et al.Assessment of agroclimate impact:Classification method of annual crop climate type(GB/T 21986-2008)(In Chinese).Beijing:Standards Press of China,2008
[23]H?gberg P.Tansleyreview No.95∶15N natural abundance in soil-plant systems.The New Phytologist,1997,137(2):179—203
[24]郭胜利,吴金水,郝明德,等.长期施肥对NO3--N深层积累和土壤剖面中水分分布的影响.应用生态学报,2003,14(1):75—78Guo S L,Wu J S,Hao M D,et al.Effect of longterm fertilization on NO3--N accumulation and moisture distribution in soil profiles(In Chinese).Chinese Journal of Applied Ecology,2003,14(1):75—78
[25]刘愫倩,徐绍辉,李晓鹏,等.土体构型对土壤水氮储运的影响研究进展.土壤,2016,48(2):219—224Liu S Q,Xu S H,Li X P,et al.Effects of soil profile configuration on soil water and nitrogen storage and transportation:A review(In Chinese).Soils,2016,48(2):219—224
[26]郭大应,熊清瑞,谢成春,等.灌溉土壤硝态氮运移与土壤湿度的关系.灌溉排水,2001,20(2):66—68Guo D Y,Xiong Q R,Xie C C,et al.Feasibility analysis on irrigation return flow reuse system in Hetao irrigation district in Inner Mongolia(In Chinese).Irrigation and Drainage,2001,20(2):66—68
[27]陈效民,邓建才,柯用春,等.硝态氮垂直运移过程中的影响因素研究.水土保持学报,2003,17(2):12—15Chen X M,Deng J C,Ke Y C,et al.Study on influence factors in process of nitrate vertical transport(In Chinese).Journal of Soil and Water Conservation,2003,17(2):12—15
[28]Nosalewicz M,Stepniewska Z,Nosalewicz A.Effect of soil moisture and temperature on N2O and CO2concentrations in soil irrigated with purified wastewater.International Agrophysics,2013,27(3):299—304
[29]Laville P,Lehuger S,Loubet B,et al.Effect of management,climate and soil conditions on N2O and NO emissions from an arable crop rotation using high temporal resolution measurements.Agricultural and Forest Meteorology,2011,151(2):228—240
[30]Follett RF.Innovative 15N microplot research techniques to study nitrogen use sufficiency under different ecosystems.Communications in Soil Science and Plant Analysis,2001,32(7/8):951—979
[31]韩晓日,郭鹏程,陈恩芬,等.土壤微生物对施入肥料氮的固持及其动态研究.土壤学报,1998,35(3):412—418Han X R,Guo P C,Chen E F,et al.Immobilization of fertilizer nitrogen by soil microbes and its changes(In Chinese).Acta Pedologica Sinica,1998,35(3):412—418
[32]Minick K J,Pandey C B,Fox T R,et al.Dissimilatory nitrate reduction to ammonium and N2O flux:Effect of soil redox potential and N fertilization in loblolly pine forests.Biology and Fertility of Soils,2016,52(5):601—614
[33]Rütting T,Boeckx P,Müller C,et al.Assessment of the importance of dissimilatory nitrate reduction to ammonium for the terrestrial nitrogen cycle.Biogeosciences,2011,8(7):1779—1791
[34]Ju X T,Gao Q,Christie P,et al.Interception of residual nitrate from a calcareous alluvial soil profile on the North China Plain by deep-rooted crops:A 15N tracer study.Environmental Pollution,2007,146(2):534—542
[2]Gao Y J,Li Y,Zhang J C,et al.Effects of mulch,N fertilizer,and plant density on wheat yield,wheat nitrogen uptake,and residual soilnitrate in a dryland area of China.Nutrient Cycling in Agroecosystems,2009,85(2):109—121
[3]Turner N C,Li F M,Xiong Y C,et al.Agricultural ecosystem management in dry areas:Challenges and solutions.Plant and soil,2011,347(1):1—6
[4]He G,Wang Z H,Li F C,et al.Soil nitrate-N residue,loss and accumulation affected by soil surface management and precipitation in a winter wheatsummer fallow system on dryland.Nutrient Cycling in Agroecosystems,2016,106(1):31—46
[5]山仑.旱地农业技术发展趋向.中国农业科学,2002,35(7):848—855Shan L.Development trend of dryland farming technologies(In Chinese).Scientia Agricultura Sinica,2002,35(7):848—855
[6]闫湘,金继运,何萍,等.提高肥料利用率技术研究进展.中国农业科学,2008,41(2):450—459Yan X,Jin J Y,He P,et al.Recent advances in technology of increasing fertilizer use efficiency(In Chinese).Scientia Agricultura Sinica,2008,41(2):450—459
[7]王西娜,王朝辉,李华,等.旱地土壤中残留肥料氮的动向及作物有效性.土壤学报,2016,53(5):1202—1212Wang X N,Wang Z H,Li H,et al.Dynamics and availability to crops of residual fertilizer nitrogen in upland soil(In Chinese).Acta Pedologica Sinica,2016,53(5):1202—1212
[8]赵伟,梁斌,周建斌.施入15N标记氮肥在长期不同培肥土壤的残留及其利用.土壤学报,2015,52(3):587—596Zhao W,Liang B,Zhou J B.Residual of applied 15N fertilizer in soilsunder long-term different patterns of fertilization and its utilization(In Chinese).Acta Pedologica Sinica,2015,52(3):587—596
[9]Dai J,Wang Z H.Li F C,et al.Optimizing nitrogen input by balancing winter wheat yield and residual nitrate-N in soil in a long-term dryland field experiment in the Loess Plateau of China.Field Crops Research,2015,181:32—41
[10]Zhou J Y,Gu B J,Schlesinger W H,et al.Significant accumulation of nitrate in Chinese semi-humid croplands.Scientific Reports,2016,6:Article number:25088
[11]Conway G R,Pretty J N.Unwelcome harvest:Agriculture and pollution.London:Earthscan Publications,1991
[12]巨晓棠,谷保静.我国农田氮肥施用现状、问题及趋势.植物营养与肥料学报,2014,20(4):783—795Ju X T,Gu B J.Status-quo,problem and trend of nitrogen fertilization in China(In Chinese).Plant Nutrition and Fertilizer Science,2014,20(4):783—795
[13]Galloway J N,Aber J D,Erisman J W,et al.The nitrogen cascade.Bioscience,2003,53(4):341—356
[14]Wang G L,Chen X P,Cui Z L,et al.Estimated reactive nitrogen losses for intensive maize production in China.Agriculture,Ecosystems&Environment,2014,197:293—300
[15]Kanter D R,Zhang X,Mauzerall D L.Reducing nitrogen pollution while decreasing farmers'costs and increasing fertilizer industry profits.Journal of Environmental Quality,2015,44(2):325—335
[16]彭琳,彭祥林,卢宗藩.塿土旱地土壤硝态氮季节性变化与夏季休闲的培肥增产作用.土壤学报,1981,18(3):211—222Peng L,Peng X L,Lu Z F.NO3--N seasonal change in dryland and fertilization production role during summer fallow of Lou soil(In Chinese).Acta Pedologica Sinica,1981,18(3):211—222
[17]Darwiche-Criado N,Comín F A,Sorando R,et al.Seasonal variability of NO3-mobilization during flood events in a Mediterranean catchment:The influence of intensive agricultural irrigation.Agriculture,Ecosystems&Environment,2015,200:208—218
[18]戴健,王朝辉,李强,等.氮肥用量对旱地冬小麦产量及夏闲期土壤硝态氮变化的影响.土壤学报,2013,50(5):956—965Dai J,Wang Z H,Li Q,et al.Effects of nitrogen application rate on winter wheat yield andsoil nitrate nitrogen during summer fallow season on dryland(In Chinese).Acta Pedologica Sinica,2013,50(5):956—965
[19]Hauck R D,Bremner J M.Use of tracers for soil and fertilizer nitrogen research.Advances in Agronomy,1976,28:219—266
[20]Sebilo M,Mayer B,Grably M,et al.The use of the ammonium diffusion method forδ15N-NH4+andδ15N-NO3-measurements:Comparison with other techniques.Environmental Chemistry,2004,1(2):99—103
[21]Brooks P D,Stark J M,Mc Inteer B B,et al.Diffusion method to prepare soil extracts for automated nitrogen-15 analysis.Soil Science Society of America Journal,1989,53(6):1707—1711
[22]吴义城,袁业畅,任耀武,等.农业气候影响评价:农作物气候年型划分方法(GB/T 21986-2008).北京:中国标准出版社,2008Wu Y C,Yuan Y C,Ren Y W,et al.Assessment of agroclimate impact:Classification method of annual crop climate type(GB/T 21986-2008)(In Chinese).Beijing:Standards Press of China,2008
[23]H?gberg P.Tansleyreview No.95∶15N natural abundance in soil-plant systems.The New Phytologist,1997,137(2):179—203
[24]郭胜利,吴金水,郝明德,等.长期施肥对NO3--N深层积累和土壤剖面中水分分布的影响.应用生态学报,2003,14(1):75—78Guo S L,Wu J S,Hao M D,et al.Effect of longterm fertilization on NO3--N accumulation and moisture distribution in soil profiles(In Chinese).Chinese Journal of Applied Ecology,2003,14(1):75—78
[25]刘愫倩,徐绍辉,李晓鹏,等.土体构型对土壤水氮储运的影响研究进展.土壤,2016,48(2):219—224Liu S Q,Xu S H,Li X P,et al.Effects of soil profile configuration on soil water and nitrogen storage and transportation:A review(In Chinese).Soils,2016,48(2):219—224
[26]郭大应,熊清瑞,谢成春,等.灌溉土壤硝态氮运移与土壤湿度的关系.灌溉排水,2001,20(2):66—68Guo D Y,Xiong Q R,Xie C C,et al.Feasibility analysis on irrigation return flow reuse system in Hetao irrigation district in Inner Mongolia(In Chinese).Irrigation and Drainage,2001,20(2):66—68
[27]陈效民,邓建才,柯用春,等.硝态氮垂直运移过程中的影响因素研究.水土保持学报,2003,17(2):12—15Chen X M,Deng J C,Ke Y C,et al.Study on influence factors in process of nitrate vertical transport(In Chinese).Journal of Soil and Water Conservation,2003,17(2):12—15
[28]Nosalewicz M,Stepniewska Z,Nosalewicz A.Effect of soil moisture and temperature on N2O and CO2concentrations in soil irrigated with purified wastewater.International Agrophysics,2013,27(3):299—304
[29]Laville P,Lehuger S,Loubet B,et al.Effect of management,climate and soil conditions on N2O and NO emissions from an arable crop rotation using high temporal resolution measurements.Agricultural and Forest Meteorology,2011,151(2):228—240
[30]Follett RF.Innovative 15N microplot research techniques to study nitrogen use sufficiency under different ecosystems.Communications in Soil Science and Plant Analysis,2001,32(7/8):951—979
[31]韩晓日,郭鹏程,陈恩芬,等.土壤微生物对施入肥料氮的固持及其动态研究.土壤学报,1998,35(3):412—418Han X R,Guo P C,Chen E F,et al.Immobilization of fertilizer nitrogen by soil microbes and its changes(In Chinese).Acta Pedologica Sinica,1998,35(3):412—418
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