Effects of tillage patterns on crop yields and soil physicochemical properties in wheat-rice rotation system

In order to study effects of tillage systems on crop yields and soil physical and chemical properties in wheat-rice rotation system, a long term (2007－2010) experiment was conducted. The results showed that compared with conventional tillage, the soil bulk density increased and soil water content decreased with no-tillage. But even without tillage, bulk density of the 0-10 cm soil layer was still suitable for the growth of crops. No-tillage enriched soil organic matter and total nitrogen in the surface soil layer. Both the soil organic matter and total N content of no-tillage were significantly higher in 0-10 cm layer and lower in 10-20 cm layer than that of conventional tillage. During the wheat season, the soil alkali N、available P and available K contents had the same trends with those of organic matter and total N. Whereas during the rice season, with no-tillage, the soil alkali N、available P and available K contents in 0-20 cm layer were lower than those of conventional tillage. The results also indicated that the treatment of no-tillage increased wheat yield, but significantly reduced rice production, and the key component of the yield was the effective panicle amount of wheat or rice. During the whole wheat-rice rotation system, the yields of wheat treated with no-tillage and the yield of rice treated with conventional tillage were 5.7% higher than wheat with conventional tillage and rice with no-tillage.