摘要
为了确定陕西关中小麦-玉米轮作区兼顾作物产量和环境效应的农田适宜氮肥用量,通过玉米-小麦-玉米连续3季田间试验研究了作物产量、氮肥利用效率、氮肥表观损失和土壤氮素平衡等对施氮量的响应。结果表明,随着氮肥用量的增加,不同年份作物产量和3季作物累计产量均表现为先增加后降低的趋势,而累计氮肥农学效率、氮肥表观利用率、氮肥吸收效率和氮肥偏生产力均表现为显著的降低趋势。土壤氮素平衡结果表明,随着施氮量的增加,低量施氮时(小麦施N<150 kg/hm2,玉米施N<180 kg/hm2),氮肥残留显著增加,表观损失和损失率变化不明显,而高量施氮时(小麦施N>150 kg/hm2,玉米施N>180 kg/hm2),氮肥残留变化不明显,表观损失和损失率却显著增加。回归和相关分析显示,矿质氮在土壤较深层次(100—200cm土层)大量累积是氮肥表观损失的重要途径之一。小麦施N 150 kg/hm2、玉米施N 180 kg/hm2时,作物即可获得相对较高的产量和氮肥利用率,且能保持作物收获前后土壤无机氮库的基本稳定,同时也可将氮肥表观损失降至较低水平。
The objective of this field study was to determine the N application rate which would both maximize yield and protect the environment in a wheat-maize rotation district of the Guanzhong Plain,Shaanxi Province.The study included six treatments replicated three times：N0（ no N application to either wheat or maize）,N1（ 113 kg N / hm2 to wheat ＋ 135 kg N / hm2 to maize）,N2（ 150 kg N / hm2 to wheat ＋ 180 kg N / hm2 to maize）,N3（ 188 kg N / hm2 to wheat ＋ 225 kg N /hm2 to maize）,N4（ 225 kg N / hm2 to wheat ＋ 270 kg N / hm2 to maize）,and N5（ 300 kg N / hm2 to wheat ＋ 360 kg N /hm2 to maize）.The study was conducted over 1.5 yr（ maize-wheat-maize）.The effects of N application rate on crop yield,N fertilizer use efficiency,apparent N loss,and N budget in the 0—100 cm depth were determined.The results showed that annual crop yield and cumulative crop yield both increased and then decreased as N application rate increased.In contrast,cumulative N agronomic efficiency,apparent N utilization,N uptake efficiency,and N partial productivity decreased significantly as N application rate increased.Calculation of the N budget in the 0—100 cm depth showed that residual mineral-N concentrations were significantly higher in the N2 treatment than in the N1 treatment,but apparent Nloss and loss rates were nearly the same in the two treatments.In contrast,residual mineral-N concentrations were nearly the same in the N3,N4,and N5 treatments,but apparent N loss and loss rate increased significantly in the order N3 N4 N5.Regression and correlation analysis indicated that excessive N fertilizer application resulted in the build-up of mineral-N concentrations in the deep soil profile.This build-up contributed significantly to apparent N loss.In conclusion,the application of 150 kg N / hm2 to wheat and 180 kg N / hm2 to maize resulted in relatively high yield and N use efficiency.These application rates also maintained residual mineral-N concentrations and reduced apparent N losses.
出处
《生态学报》
CAS
CSCD
北大核心
2014年第21期6115-6123,共9页
Acta Ecologica Sinica
基金
公益性行业(农业)科研专项(20100314)
高等学校学科创新引智计划(B12007)
关键词
小麦-玉米轮作体系
适宜施氮量
产量
残留
表观损失
wheat-maize rotation system optimal N rate yield mineral-N residual apparent N loss
