Effect Study Of Paddy Conservation Tillage On Soil Physicochemical Properties Of Sichuan

The core of agricultural sustainable development is improving land productivity constantly, and at the same time, improving ecological environmental quality constantly. To achieve this goal, paddy no-tillage is an effective method.Taking the 9 protections cultivation ways which carried on in Wenjiang, Shuangliu, Mianzhu and Zhongjiang as the basic materials. This paper studied the changes of the soil physicochemical properties and the output under two kinds of cropping systems paddy no-tillage and paddy tillage, The results are as follows:No matter in material circulation or energy changes paddy conservation tillage ecosystem is different from convention tillage. Through the change of the field micro-relief which was caused by the CT, the soil phase structure had been changed essentially. Through analyzing, conservation tillage did not cause the soil to harden etc,and can reduce the soil bulk density in various degree, improved the structure characteristic of the soil. Among several conservation tillage ways, the most low soil bulk density was the no-tillage for four year and half cover (F) in Wenjiang district which was only 1.19g/cm~3. Compared with convention tillage, the soil bulk density value reduced 13.77%. While the highest value region lied in Zhongjiang County. The results showed that soil bulk density value reduced obviously in Wenjiang which had carring on conservation tillage three to four years which was superior to Mianzhu of no-tillage for six year and all cover. Moreover,if proper ploughing was done after three to four years no-tillage, the soil bulk density would be reduced, while the soil structure would be improved. Therefore, it was not that the soil bulk density presented decreasing tendency as the increase of the no-tillage year.After continuous no-tillage in paddy field, the soil organic matter of the surface layer increased. Comparing with the convention tillage, the soil organic matter in 0-20cm had increased 29.81% under no-tillage for 6 years and all cover. This showed obvious changing degrees which were closing related to the no-tillage year. The soil organic matter under various way reduced with the increase of soil profile depth. The content of STP under CT varied between 0.58-1.97g/kg, while under routine cultivation the content varied between, which indicated that the content of STP had increased in some extend after CT. Content of the total K of the top layer under CT was between 18.52-29.80g/kg, while content of the total K of ground floor was only 9.36-15.31g/kg; Correspondingly, under convention tillage,the range of variation was between in 13.01-24.29g/kg from the top soil to the 20-40cim, while the content of total K under CT varied greatly.Paddy no-tillage can also influence soil available content of nutrient,compared with the convention tillage, soil available N content supreme cultivation way 0-20cm is no-tillage six year + no-cover (H), it is 139.35mg/kg. Available P of conservation tillage and available K concentrate on the soil top layer mainly, in the 20-40cm, available P and available K relatively less, different cultivation and straw return field way to soil available P and available K difference influence among the different levels soil.Paddy long-term ridge culture can improve crop output, among the five years past 1999-2003, 9 different protective cultivation way raise than convention output of cultivation to some extent, Shuangliu county no-tillage two year+total cover(Bi?) the average per mu yield of wheat up to 364.46kg, but Mianzhu city no-tillage six year+all cover output average per mu yield covered to have up to 517.04kg, more than the convention tillage output 3.81% and 3.67%. This has good soil structure because of the soil of conservation tillage for years, suitable soil bulk density, can better preservation and release nutrient, possess assuaring water conservancy and personning who keep in touch with strong at the same time, can offer the fine environment for growth of the crop.lt is remarkable to implement the ecology of protective cultivation, economic benefits, realizing the soil fosters and apply fertilizer and structure reconstruction, have fully utilize resources of the straw, has prevented the field from burning and polluting the environment, ecological environment protection.The results showed that paddy conservation tillage had a certain improvement function to the soil physicochemical properties, the output of different cultivation ways under conservation tillage had improved in various degrees. In this way, therefore, remarkable social, ecological benefits could be achieved .