Effects of tillage systems on fields in Chengdu plain. I. The effects of tillage systems on soil properties and crop yields.

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.