秸秆还田下冬小麦产量效应及对土壤硝态氮保持作用研究

发布时间：2019-03-27 20:17

【摘要】：关中平原是典型的小麦-玉米轮作区,秸秆还田已经成为常规农业措施。为了能够给秸秆还田下冬小麦增产和氮肥优化管理提供科学依据,在关中地区周至县和武功县两个试验点设立田间长期试验,采用裂区设计,试验为裂区设计,主处理是玉米全部还田(N+S)和玉米秸秆不还田(S),副处理是5个分别为N0、84、168、252和336 kg N/hm2的施氮水平。获得的主要结论如下:1、连续5年的田间定位试验(周至县)结果表明,秸秆还田与秸秆不还田条件下氮肥效应曲线呈相交趋势,5年试验的交点分别为153、187、99、146和115 kg/hm2;施氮量低于交点时秸秆还田处理小麦产量低于秸秆不还田处理:这5年N0处理减产分别达到3.0%、8.4%、18.8%、14.5%和9.1%;但是高于曲线交点施氮量时,秸秆还田处理能增加小麦产量,这5年不同处理中秸秆还田比不还田处理最高增产率分别是7.2%、5.6%、9.5%、5.8和7.5%。另一试验点武功县试验地氮肥效应曲线规律与周至县一致,武功县2013和2015年试验氮肥效应曲线交点分别为119和106 kg/hm2,这两年秸秆还田相比秸秆不还田小麦最高增产率分别是9.5%和8.9%。2、秸秆还田配施适量氮肥可以增加冬小麦各器官氮、钾含量,以及茎叶和颖壳的磷含量。秸秆还田处理能提高冬小麦地上部氮磷钾养分吸收量,其中对吸钾量影响最显著,周至县秸秆还田下冬小麦地上部吸钾量增幅为7.2%~13.7%,武功县增幅为12.2%~26.0%。3、秸秆还田条件下土壤耕层0~20cm有机质含量总体高于秸秆不还田处理。2012-2016年秸秆还田处理下土壤有机质相比秸秆不还田,有机质整体增加幅度分别为4.4%、6.6%、4.2%、7.0%和6.8%;5年间增幅最高的处理分别为N168、N0、N84、N84和N0,秸秆还田与等氮量不还田处理相比较增幅达15.9%、10.7%、11.0%、22.5%和7.0%。4、小麦收获后2m土层硝态氮累积残留量随着施氮量的增加而升高,秸秆还田具有明显的保持土壤硝态氮作用。玉米秸秆还田有利于冬小麦收获后0~2m土壤中硝态氮的累积,2012~2016年秸秆还田比秸秆不还田处理土壤硝态氮累积量分别平均增加25.1、8.9、64.5、65.8和7.5 kg/hm2;增加幅度分别为25.4%、3.4%、13.5%、24.0%和1.7%。
[Abstract]:Guanzhong Plain is a typical wheat-maize rotation area, straw return has become a conventional agricultural measure. In order to provide scientific basis for yield increase and optimal management of nitrogen fertilizer in winter wheat under straw return, a long-term field experiment was set up in Zhouzhi County and Wugong County in Guanzhong region. The design of split area was adopted and the experiment was designed for split area. The main treatment was N _ 0, 84168252 and 336 kg N/hm2 nitrogen application levels of all maize returning (N S) and corn straw non-returning (S), secondary treatment were N _ 0, 84168252 and 336 kg N/hm2, respectively. The main conclusions are as follows: 1. The results of 5-year field experiment (Zhouzhi County) showed that the nitrogen fertilizer effect curves of straw returning and non-returning showed an intersecting trend, and the intersection points of the five-year experiment were 153, 187, 99146 and 115 kg/hm2;, respectively. The wheat yield of straw returning treatment was lower than that of straw non-returning treatment when nitrogen application rate was lower than that of straw non-returning treatment: the yield reduction of N _ 0 treatment was 3.0%, 8.4%, 18.8%, 14.5% and 9.1% respectively in these five years; But when nitrogen application rate was higher than curve crossing point, straw returning treatment could increase wheat yield. The highest yield of straw returning treatment was 7.2%, 5.6%, 9.5%, 5.8% and 7.5%, respectively. The curve of nitrogen fertilizer effect in Wugong county was consistent with that in Zhouzhi county. The intersections of nitrogen fertilizer effect curve in Wugong county in 2013 and 2015 were 119 and 106 kg/hm2, respectively. The highest yield of wheat returned by straw was 9.5% and 8.9%, respectively. The nitrogen, potassium and phosphorus contents of stem, leaf and glume of winter wheat could be increased by applying appropriate amount of nitrogen fertilizer when straw returned to field in the past two years, compared with that of wheat without straw returning to the field in the past two years, the yield of wheat was increased by 9.5% and 8.9%, respectively. Straw returning treatment could increase the uptake of nitrogen, phosphorus and potassium in the upper part of winter wheat, among which, the most significant effect was on the uptake of potassium, and the increase of potassium uptake was 7.2% ~ 13.7% under the straw return in Zhouzhi County, and the growth rate of potassium uptake in winter wheat was 7.2% and 13.7%, respectively. In Wugong County, the increase was 12.2% / 26.0%. The content of 0~20cm organic matter in tillage layer under straw returning was higher than that in straw non-returning treatment. In 2012-2016, soil organic matter in tillage layer was higher than that in straw non-returning treatment. The overall increase of organic matter was 4.4%, 6.6%, 4.2%, 7.0% and 6.8%, respectively. The highest growth rates in the five-year period were N168, N0, N84, N84 and N0, respectively. The increase in straw return to field was 15.9%, 10.7%, 11.0%, 22.5% and 7.0% compared with the non-return treatment with equal nitrogen amount, and the increase was 15.9%, 10.7%, 11.0%, 22.5% and 7.0% respectively. After harvest, the accumulation of nitrate nitrogen in 2m soil layer increased with the increase of nitrogen application rate, and straw returning had obvious effect of retaining nitrate nitrogen in soil. The return of corn straw to field was beneficial to the accumulation of nitrate nitrogen in 0 ~ 2 m soil after harvest of winter wheat. In 2012 / 2016, the accumulation of nitrate nitrogen in soil increased by 25.1, 8.9, 64.5, 65.8 and 7.5 kg/hm2;, respectively, compared with that of non-returning straw treatment. The increases were 25.4 percent, 3.4 percent, 13.5 percent, 24.0 percent and 1.7 percent, respectively.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S512.11;S141.4

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