不同耕作措施对陇中黄土高原旱作农田土壤团聚体稳定性的影响

发布时间：2018-03-26 10:08

  本文选题：团聚体组成和稳定性　切入点：LB法　出处：《甘肃农业大学》2015年硕士论文

【摘要】：为探明不同耕作措施对土壤团聚体稳定性以及团聚体中有机碳、全氮、全磷的影响,借助干筛法、约得尔法和LB法分析团聚体稳定性,依托布设于陇中黄土高原雨养农田豆-麦双序列轮作系统的不同耕作措施长期定位试验,共设4种耕作措施:传统耕作(T)、免耕不覆盖(NT)、传统耕作+秸秆还田(TS)、免耕+秸秆覆盖(NTS),旨在探索适合于该区农业可持续发展、环境友好型、减缓水土流失且提高土壤固碳和养分的最佳耕作模式,主要结论如下:1.保护性耕作措施均可提升团聚体含量和稳定性,免耕+秸秆覆盖处理效果最好。耕作措施对团聚体组成的影响各不相同,但是较之传统耕作措施,免耕、传统耕作+秸秆还田和免耕+秸秆覆盖均可不同程度提高≥0.25mm机械稳定性和水稳性团聚体含量,也可提升机械稳定性和水稳性团聚体平均重量直径(MWD),降低团聚体破碎率(PAD),综合来看,NTS处理效果最优。2.保护性耕作措施可提升团聚体抗水蚀能力,免耕+秸秆覆盖处理效果最好。快速湿润法、慢速湿润法和预湿润后扰动法处理后,各土层中均以免耕+秸秆覆盖措施水稳性团聚体MWD和≥0.25mm水稳性团聚体含量最高。因此,免耕+秸秆覆盖处理对减缓由“气爆”、“水爆”以及雨滴打击而引起的团聚体崩解的效果最好。3.保护性耕作各措施可提升团聚体固碳、氮、磷的能力,其中免耕+秸秆覆盖处理效果最好,同时微团聚体固定有机碳、全氮和全磷的能力高于大团聚体的。不同耕作措施下各粒级团聚体中有机碳、全氮、全磷含量均以免耕+秸秆覆盖处理最高,传统耕作+秸秆还田处理次之。不同耕作措施0.25mm粒级微团聚体中有机碳、全氮和全磷含量普遍高于其他粒级的。
[Abstract]:In order to investigate the effects of different tillage practices on the stability of soil aggregates and the organic carbon, total nitrogen and total phosphorus in the aggregates, the stability of the aggregates was analyzed by means of dry sieve method, Yorkshire method and LB method. The long-term localization experiment of different tillage measures based on the double sequence rotation system of soybean and wheat in the rain-fed farmland on the Loess Plateau in the middle of Gansu Province was carried out. There were four kinds of tillage measures: traditional tillage, no mulching, no mulching, no straw returning to field, no tillage straw mulching NTS, in order to explore suitable for the sustainable development of agriculture in this area, and environmental friendly type. The main conclusions are as follows: 1. Conservation tillage can improve aggregate content and stability. The effect of no-tillage straw mulching was the best. The effect of tillage on aggregate composition was different, but compared with traditional tillage, no-tillage was the best. The mechanical stability of 鈮，

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