本文選題：團聚體組成和穩(wěn)定性　切入點：LB法　出處：《甘肅農(nóng)業(yè)大學》2015年碩士論文

【摘要】：為探明不同耕作措施對土壤團聚體穩(wěn)定性以及團聚體中有機碳、全氮、全磷的影響,借助干篩法、約得爾法和LB法分析團聚體穩(wěn)定性,依托布設于隴中黃土高原雨養(yǎng)農(nóng)田豆-麥雙序列輪作系統(tǒng)的不同耕作措施長期定位試驗,共設4種耕作措施:傳統(tǒng)耕作(T)、免耕不覆蓋(NT)、傳統(tǒng)耕作+秸稈還田(TS)、免耕+秸稈覆蓋(NTS),旨在探索適合于該區(qū)農(nóng)業(yè)可持續(xù)發(fā)展、環(huán)境友好型、減緩水土流失且提高土壤固碳和養(yǎng)分的最佳耕作模式,主要結論如下:1.保護性耕作措施均可提升團聚體含量和穩(wěn)定性,免耕+秸稈覆蓋處理效果最好。耕作措施對團聚體組成的影響各不相同,但是較之傳統(tǒng)耕作措施,免耕、傳統(tǒng)耕作+秸稈還田和免耕+秸稈覆蓋均可不同程度提高≥0.25mm機械穩(wěn)定性和水穩(wěn)性團聚體含量,也可提升機械穩(wěn)定性和水穩(wěn)性團聚體平均重量直徑(MWD),降低團聚體破碎率(PAD),綜合來看,NTS處理效果最優(yōu)。2.保護性耕作措施可提升團聚體抗水蝕能力,免耕+秸稈覆蓋處理效果最好�？焖贊駶櫡�、慢速濕潤法和預濕潤后擾動法處理后,各土層中均以免耕+秸稈覆蓋措施水穩(wěn)性團聚體MWD和≥0.25mm水穩(wěn)性團聚體含量最高。因此,免耕+秸稈覆蓋處理對減緩由“氣爆”、“水爆”以及雨滴打擊而引起的團聚體崩解的效果最好。3.保護性耕作各措施可提升團聚體固碳、氮、磷的能力,其中免耕+秸稈覆蓋處理效果最好,同時微團聚體固定有機碳、全氮和全磷的能力高于大團聚體的。不同耕作措施下各粒級團聚體中有機碳、全氮、全磷含量均以免耕+秸稈覆蓋處理最高,傳統(tǒng)耕作+秸稈還田處理次之。不同耕作措施0.25mm粒級微團聚體中有機碳、全氮和全磷含量普遍高于其他粒級的。
[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，

本文編號：1667442