秸秆还田及不同比例控失尿素对华北平原小麦产量及潮土性质影响

Effects of different proportions of loss-control urea on properties of fluvo-aquic soil and wheat yield in north China

为探讨不同控失尿素比例和秸秆还田对华北平原小麦产量及潮土化学性质的影响,本研究以华北潮土区小麦-玉米轮作体系为研究对象,采用裂区试验设计,以秸秆还田为主区,控失尿素比例为副区。秸秆还田模式设秸秆全量还田(S1)、秸秆不还田(S0)2种;控失尿素比例设不施肥(CK)以及控失尿素占总施氮量比例为0、40%、70%和100%(LCU0、LCU40、LCU70、LCU100)5个处理。在作物收割后进行产量测定,并采集0~20 cm耕层土壤进行常规土壤养分含量测定。结果表明:与S0处理相比,S1处理显著提高土壤有机质和速效钾含量。控失尿素显著提高土壤硝态氮含量,其他土壤养分含量无显著变化。秸秆不还田条件下,施用化肥显著降低了土壤pH值。控失尿素比例为70%时土壤养分含量最高。秸秆还田对小麦产量及吸氮量无显著影响,控失尿素对小麦产量及吸氮量增加具有极显著影响。在所有处理中,S1-LCU40处理的籽粒和秸秆产量最高,籽粒产量达7009.26 kg·hm^(-2),秸秆产量达11361.38 kg·hm^(-2)。秸秆还田对土壤氮素依存率具有显著影响,不同比例控失尿素对氮素收获指数具有显著影响,对氮肥表观利用率、土壤氮素依存率具有极显著影响。控失尿素比例为40%或70%时氮素吸收利用指标较优。综上,在华北平原潮土区,秸秆还田与40%控失尿素比例配施可以显著提升土壤供氮能力,提高小麦产量和氮素吸收与利用指标,是较为适宜的管理措施,但其机理及长期效应还需进一步研究。

In this study,effects of loss-control urea ratio on the nutrients of fluvo-aquic soil and crop yield in north China under straw returning and non-returning conditions were evaluated.The wheat-maize rotation system in fluvo-aquic soil in north China was used in this experiment.The design of splitting plots was adopted,with straw returning as the main area and loss-control urea ratio as the sub-area.Two methods of straw returning were adopted:straw returning and non-returning,expressed as S1 and S0,respectively.Additionally,five treatments were set up for no fertilization(CK)and different loss-control urea ratios which were 0,40%,70%,and 100%of the total nitrogen application(LCU0,LCU40,LCU70,and LCU100),respectively.Crop yields were measured and 0–20 cm of topsoil was collected for routine soil chemical property measurements after harvest.The results showed that compared with the S0 treatment,the S1 treatment significantly increased soil organic matter and available potassium contents.Loss-control urea significantly increased soil nitrate nitrogen content.Other soil chemical properties also increased,but the difference was not significant.Under the condition of straw not returning to the field,the application of chemical fertilizer significantly reduced the soil pH.When the ratio of loss-control urea was 70%,the soil nutrients were greatly improved.No significant effect of straw returning to the field was observed on wheat yield and nitrogen uptake,but loss-control urea had a significant effect on wheat grain yield,straw yield,total nitrogen content,and total nitrogen uptake.The grain and straw yields of the S1-LCU40 treatment were the highest under different treatments,with a grain yield of 7009.26 kg·hm^(−2),and a straw yield of 11361.38 kg·hm^(−2).Straw returning had significant effects on soil nitrogen dependence rate,and different proportions of loss-control urea had significant effects on nitrogen harvest index,apparent nitrogen recovery efficiency,and nitrogen dependence rate.The best nitrogen absorption and utilization index was 40%or 70%.Overall,in the North China Plain,straw return to soil and 40%loss-control urea could significantly increase soil nitrogen supply,wheat yield,and index of nitrogen uptake and utilization,which constitutes a more appropriate management measure,but its mechanism and long-term effect need to be further studied.