Effects Of Tillage And Crop Residue Management Soil Biological Properties And Plant Growth In A Winter Wheate-summer Maize Cropping Systems

: The soil shallow topsoil, the tightly structure and the few effective topsoil soilquantity are becoming one of the limit factors to improve grain yield in Huang huai hai Area.By using the combined technology of increasing tillage depth and straw returned, we build adeep loose topsoil, improve the validity of the top layer soil nutrients，promote soil biologicalactivity, which is one of main methods to realize the huang-huai-hai region of high and stableyield crop. To overcome soil compaction and improve soil quality, the effects of the farmingmethods, the straw returned and the interactiong on the physical, chemical and biologicalproperties. The results were as follows:1Deep or subsoil tillage and straw returned can reduce soil bulk density, improve waterstorage enhance, soil temperatur and organic carbon. the interaction of tillage and strawreturned significantly effect on physical and chemical properties of soil. Compared withconventional tillage with no straw returning, the deep tillage with straw returning and subsoiltillage with straw returning lead to the soil compaction and soil bulk density of20-30cmdecreased by34.1%and25.7%,8.5%and6.6%, respectively;the moisture increased by16.7%and11.2%,,the soil temperature increased by5.8%and3.5%, the organic carbonincreased by14.8%and12.4%.2Deep or subsoil tillage and straw returned can increase soil microbial community andsoil enzyme activities significantly. Compared with conventional tillage, deep tillage andsubsoil tillage lead to the soil microbial community of20-30cm and30-40cm increased by47.0%and35.5%,70.2%and49.6%; the soil enzyme activities of20-30cm and30-40cmincreased by34.2%and25.4%,52.9%and45.6%.The soil microbial community and theenzyme activities increased by24.1%and14.5%after straw returned. The interaction oftillage and straw returned significantly effect on soil biological activity. Compared withconventional tillage with no straw returning, the deep tillage with straw returning and subsoil tillage with straw returning lead to the soil microbial community and the enzyme activitiesincreased by58.1%and56.5%,34.5%and32.3%.3Soil tillage, straw returning and their interaction significantly effect on soil respiration.Deep or subsoil tillage and straw returned can significantly increase soil respiration. Strawreturning increased soil respiration during winter wheat season, but decreased soil respirationduring summer maize season. The interaction of tillage and straw returned significantly effecton soil respiration. Compared with conventional tillage with no straw returning, the deeptillage with straw returning and subsoil tillage with straw returning lead to the soilrespirations increased by32.6%and30.2%.4Deep or subsoil tillage and straw returned can increase crop biomass production andeconomic yield. Compared with conventional tillage, deep tillage and subsoil tillage lead tothe dry matter accumulation increased by30.9%and25.3%, the root dry weight densityincreased by30.9%and25.3%, the grain yield increased by10.7%and9.8%, respectively.After straw returned, the dry matter accumulation increased by12.3%, the root dry weightdensity increased by13.0%, the grain yield increased by8.3%, respectively. The interaction oftillage and straw returned significantly effect on dry matter accumulation, the root dry weightdensity and the grain yield. Compared with the conventional tillage with no straw returned,the dry matter accumulation of the deep tillage with straw returning and subsoil tillage withstraw returning increased by19.3%and22.9%, the root dry weight density increased by44.3%and40.0%, the grain yield increased by18.0%and19.3%.respectively.5Crop yield and soil physical, biological traits were significantly correlated. The soilrespiration was significantly positively correlated with soil temperature, soil moisture and soilcarbon, while negative correlated with soil compaction. The soil temperature was the mostimportant factor which affected soil respiration. The soil bulk density was significantlynegative correlated with the content of soil organic carbon, microorganism quantity enzymeactivity and grain yield. Meanwhile, the microorganism quantity was significantly positivelycorrelated with enzyme activities. These results suggested that tillage and straw returning canincrease grain yield by improving microorganism quantity and enzyme activities anddecreasing soil bulk density.