免耕覆盖对玉米产量及土壤肥力的影响

在10a玉米连作的基础上,研究免耕覆盖和传统耕作对玉米产量和养分吸收的影响及土壤养分的变化。结果表明:免耕覆盖可以增产1 012.5kg/hm2,增产率为17.6%。免耕覆盖可以减少玉米根部和茎叶对氮素的吸收,从而增加玉米籽粒中氮素含量;同时可以促进茎叶中的钾元素向籽粒和根部转移。免耕覆盖土壤有机质、全氮、全磷、碱解氮含量比传统种植分别增加38.7%、22.8%、67%、41.6%,速效钾增幅较小,为3.0%,速效磷含量则表现为传统耕作比免耕覆盖高出1.20mg/kg。在免耕覆盖和传统耕作下,土壤硝态氮含量随土层深度的增加,均呈现先升高后降低的趋势,并且不同层次之间差异显著;免耕覆盖在110cm左右出现最大累积峰,而传统耕作最大累积峰出现在60cm左右。

Effect of No-tillage with Straw Cover on Corn Yield and Soil Fertility

This research is based on the 10-years continuous cropping of maize to study the changes of corn yield and soil nutrients under different tillage measures. The results showed no-tillage with straw cover can yield 1 012.5 kg/hm, and the increasing rate was 17.6%. No-tillage with straw cover can reduce the uptake of nitrogen into corn roots and cauline leaves, and increase the content of nitrogen in corn seeds; in the meantime, can promote the transference of potassium from cauline leaves to roots and seeds. Compared to traditional cultivation, the soil organic matter of no-tillage with straw cover increased by 38.7%, total nitrogen increased by 22.8%, total phosphorus increased by 67%, alkali-hydrolyzable nitrogen increased by 41.6% , and available potassium increased by 3.0%; while available phosphorus under traditional cultivation was 1.20 mg/kg higher than that under no-tillage with straw cover. Whether traditional cultivation or no-tillage with straw cover, with the increasing of soil depth, the content of soil nitric nitrogen increased at first, then decreased, and was significantly different among different soil layers. The maximum cumulative peak of nitric nitrogen occurred at 60 cm under traditional farming, and it occurred at 110 cm under no-tillage with straw cover.