The Effects Of Different Tillage Styles And Straw-Returning On Soil Nutrient And Carbon Pool From Rice-Wheat Rotation Fields

The crops straw is important biological resources,as a large agricultural nation,in china,hundred million tons of straw is idled or burned,which cause the straw resource wasted and low utilization rate,meanwhile cause some environment problem such as pollution.This test were carried out at changwang village of YouFang town in yangzhong city of jiangsu province in2009-2011.the field experiment research the infuluence of Straw returning and Tillage regime on soil nutrient and soil carbon pool in the system of two rice-wheat farming,aiming to improve soil fertility and the rate of resources utilization,to provide scientific basis for improving soil properties and achieving high yield, high efficiency and sustainable crop safety production; to provide theoretical reference for realizing the sustainable development of agriculture, the countryside ecological environment protection and the clean production.The main conclusions of experiment are as follows:1. The influence of different cultivation and straw returning to soil nutrientThe straw returning significantly improve the soil total nitrogen, phosphorus, alkali solution nitrogen, rapidly-available phosphorus and rapidly-available potassium content whether spin tillage or tillage, total nitrogen, total phosphorus, alkali solution nitrogen, rapidly-available phosphorus and rapidly-available potassium content, both present: rice-wheat straw returning>rice straw returning>wheat straw returning>no returning,and the differences between rice-wheat straw returning and no returning reach significant level,but the content between rice straw returning and wheat straw returning have no significant difference.Tillage styles have a significant influence on soil phosphorus and rapidly-available potassium, and to the total phosphorus, the influence of plow spin significant higher than tillage. For rapidly-available potassium, the influence of tillage significantly greater than spin crops.The the most significant combination of The interaction effects of Straw returning and Tillage regime on soil total nitrogen, phosphorus, alkali solution nitrogen and phosphorus content is spin tillage+wheat-rice stalks returning; The the most significant combination of The interaction effects of Straw returning and Tillage regime on rapidly-available potassium content is tillage+wheat stalks returning.2. The influence of different farming methods and straw returned way to the soil carbon libraryThe straw returning can significantly improve soil total organic carbon and microbial biomass carbon content, and can significantly influence vertical distribution of soil total organic carbon and microbial biomass carbon,as follows:0～7cm>7～15cm>15～25cm,and all gradation reached the significant difference level.The influence of difference Tillage styles on soil total organic carbon and the microbial biomass carbon content have also reached the level of significance, but embodied in15～25cm, and tillage is significantly higher than spin tillage. And for0～7cm and7～15cm soil total organic carbon and microbial biomass carbon content, there is no significant difference between tillage and spin tillage.The straw returning can significantly improve the soil water soluble organic carbon and water stability reunion body organic carbon content. The influence Of Different Tillage regime on soil water soluble organic carbon content reached the significant difference level, performance for the spin plow processing significant higher than tillage processing. Different Tillage styles have significant influence on soil water stability reunion body organic carbon content, for0.5～0.25mm,2～1mm,5～3mm and>5mm particle size, spin tillage of water stability reunion body organic carbon content was significantly higher than tillage.The most significant combination of The interaction effects of Straw returning and Tillage styles on0～7cm and7～15cm soil total organic carbon and microbial biomass carbon content is spin tillage+wheat-rice straw returning.however the the most significant combination of The interaction effects of Straw returning and Tillage styles on15～25cm soil total organic carbon and microbial biomass carbon content is tillage+wheat-rice stalks returning.The combination of the most significant impact on the soil organic carbon and water-soluble water stability reunion body organic carbon is spin tillage+wheat-rice straw returning.