Abstract:

【Objective】 In order to provide a theoretical basis for the main tillage systems and control technology of Chengdu plain, the effects of different tillages on soil properties and yield were compared. 【Method】 Based on long-term experiments, 5 years of field trials were carried and the tillages on crop yield and soil properties and their relationship were analysed. The five treatments were wheat and rice conventional tillage (WRCT); wheat no-tillage and rice conventional tillage (WNRCT); wheat and rice no-tillage (WRNT); wheat and rice ridge tillage (WRRT); wheat no-tillage and rice conventional tillage and autumn vegetable no-tillage (WNRCVNT).【Result】 The effects of different tillage systems on soil properties were different: Compared with the control, single and double no-tillage all reduced soil bulk density of the 0-10 cm layer, increased that of the 10-20 cm layer; which increased the small soil porosity, and increased the big soil porosity of the 0-10 cm layer, while increased the proportion of small pores, decreased the big soil porosity of the 10-20 cm layer, which improved the soil pore size distribution. It was not significantly different in soil specific gravity and soil hygroscopic water between tillage treatments. No-tillage decreased the soil specific gravity. The seepage rate of soil was increased too, which was not good for rice growth. No-tillage increased the soil organic. No-tillage straw mulching reduced alkalescence of the 0-10 cm soil layer, but increased alkalescence of the 10-20 cm soil layer. The average yield of five years showed that no-tillage increased wheat production, but significantly reduced rice production. 【Conclusion】 No-tillage resulted in the formation of “loose above and compact below” soil structure, which changed the soil permeability. Especially in the 10-20 cm, it broke the traditional plowpan. But no-tillage changed the soil structure which the effects on wheat and rice yield is not consistent. Under the same conditions, no-tillage is beneficial to increase wheat yield, but it is negative to rice growth and yield. The reason mainly due to no-tillage increased the rates of soil water seepage, and it caused leakage of water and nutrients seriously.

Key words: Chengdu Plain, tillage systems, soil properties, crop yield