不同保护性耕作措施对黄土高原旱作农田土壤物理结构的影响

选取黄土高原半干旱区连续4年进行保护性耕作的玉米样地,定位试验,研究了不同耕作方式对耕层土壤理化性质的影响。结果表明:免耕秸秆覆盖(NTS)可显著降低0~5 cm表层土壤容重,传统耕作秸秆粉粹还田(TS)和NTS处理可显著降低5~10 cm、10~30 cm土层的土壤容重;NTS处理可显著增大0~5 cm表层土壤孔隙度,TS和NTS处理可显著提高5~10 cm1、0~30 cm土层的土壤孔隙度;NTS处理可显著降低各层土壤的坚实度,其它处理对表层0~5 cm无显著影响,免耕无秸秆覆盖(NT)处理显著增加了5 cm以下的土壤坚实度;NTS处理0~5 cm表层土壤水分入渗率显著加强,而NT处理则显著减弱;土壤水稳性大团聚体含量均为:NTSNTTS传统耕作(T)。本试验中NT处理对土壤结构的改良效应不明显,NTS处理对于黄土高原土壤结构改良效果最佳。

The effects of different conservation tillage on soil physical structures of dry farmland in the Loess Plateau

In order to investigate the effects of different tillage practices(T:conventional tllage, TS:conventional tillage with straw incorporated, NT:no-tillage without straw covering, NTS:no-tillage with straw covering) on soil physi-cal and chemical properties in plough layer, an experiment was conducted at corn plots with conservational tillage for four years in and and semiarid areas of the Loess Plateau. The results showed that, NTS treatment may significantly reduce the soil bulk density of 0~5 cm layer, TS and NTS treatments may significantly reduce the soil bulk density of 5~10 cm and 10~30 cm layer; NTS can significantly increase the soil porosity of 0~5 cm layer, TS and NTS may significantly improve the soil porosity of 5~10 cm and 10~30 cm layers; NTS treatment may significantly reduce the level of soil compaction of each layer, and other treatments have no significant efecte on the top 0~5 cm layer, while NT treatment significantly increases the soil compaction below 5 cm; NTS increases the soil hydraulic conductivity of 0~5 cm layer, while the NT treatment significantly reduces it; the content of large water- stable aggregates is listed as NTS> NT> TS>T. Based on our research, so NT treatment has no remarkable effect on the improvement of soil physical structures, while NTS treatment has the best performance.