西北半干旱区秸秆带状覆盖对小麦根际土壤微生物群落结构及活性的影响

In order to resolve the contradictions between water conservation and decreasing temperature with the use of traditional straw covering, bundled straw covering technique had been innovated by college of agronomy, Gansu agricultural university, which was designed by partial mulching as＂planting area with no cover, covering area with no planting＂. It has been proved that wheat grain yield can be increased significantly by the ratio of 43.5%(19.1%～128.8%) with the use of straw bundled covering technique compared to no cover. Aiming to analyze the mechanism of increasing yield and efficiency of straw bundled covering, the experiment will be designed with the treatments such as straw bundled covering, plastic film mulching and no cover, the effects of temporal and spatial changes of soil water and temperature on the microbial community structure and activity in wheat rhizosphere soil, the crop growth index and the yield components will be studied. The results of the project will provide the theoretical guidance to the promotion and application of straw bundled covering cultivation technology, build the theoretical foundation for improving the ecological environment of agricultural production and promoting the sustainable development of wheat cultivation in Northwest China.

秸秆带状覆盖技术是由甘肃农业大学农学院研发的旱地覆盖保墒栽培新技术，即采用“种的地方不覆盖、覆盖的地方不种”局部覆盖思路，解决了传统秸秆覆盖保墒与降温的矛盾限制。2013-2016年4年专家实产测定证明，该技术种植旱地冬小麦平均较不覆盖显著增产43.5%（19.1%～128.8%），产量与地膜覆盖相近。本研究以地膜覆盖和无覆盖露地栽培为对照，研究秸秆带状覆盖栽培下土壤水温动态对小麦根际土壤微生物群落结构及活性的影响，作物生长指标及产量结构要素，旨在深入剖析秸秆带状覆盖栽培技术的增产增效机理。项目成果可为秸秆带状覆盖栽培技术在西北半干旱区的推广应用提供理论指导，为改善该区域农业生产生态环境、促进小麦种植可持续发展奠定理论基础。

本项目在2018-2021年4个不同降水年型比较研究了秸秆带状覆盖、全地面地膜覆盖及无覆盖露地种植条件下麦田0-20cm土层土壤水温、微生物活性及微生物菌群结构的差异，从土壤微生态角度分析了秸秆带状覆盖的增产增效机理。研究表明，土壤水温是影响微生物菌群结构及微生物活性的主要因素，秸秆带状覆盖处理的种植带具有适宜的水温环境，有利于微生物细菌和真菌多样性和丰度的提高，特别细菌中的变形菌门丰度的提高对脲酶、蔗糖酶、过氧化氢酶活性的变化有积极的作用，可以调节根的生长、促进营养吸收，有利于提高小麦有效穗数，是秸秆带状覆盖增产的主要原因之一。秸秆覆盖带有突出的保墒效应，水分条件的改善有利于微生物多样性和丰度的提高;显著的降温效应抑制了土壤脲酶活性，但在孕穗期和灌浆期碱性磷酸酶活性高于种植带，利于磷肥的活化，为小麦生长及粒重形成提供有效磷。