Effects On Soil Fertility Under Different Tillage Types And Rotations In Fluvo-aquic Soil In Henan Province

The field experiment was carried out in Yanling country farm,Xuchang City,Henan Province China,in order to study the effects of straw returning and four soil tillage types(including zero-tillage, rotary-tillage(15cm),shallow-tillage(22cm) and deep-tillage(32cm)) and three rotations(including wheat/maize, wheat/peanut and wheat/soybean)on the yield and its components in wheat , soil physicochemical properties, dynamic change of nitrate reductase,urease,phosphatase activities and soil microbial biomass carbon and nitrogen from 2007 to 2008. In this experiment wheat cultivars Xinmai 19, maize cultivars Zhengdan136,peanut cultivars yuhua 14 and soybean cultivars Xudou 3 were used.Meanwhile, physiological & biochemical were also studied.The results were summed up as below:1. Effects on the yield components in wheat under different tillage typesDifferent tillages affect the yield and its components in wheat.The biomass,weight of glume,mean length , total spike grain weight of wheat and 1000-grain weight of rotary-tillage was the highest in the four treatments.But the 50cm three rows total spikes of it was less than no-tillage treatment,so its yield.The yield of shallow-deep was the third,The yield components in wheat yield of deep-tillage treatment was the lowest in the four treatments,and so its yield.2. Effects on soil physical properties in different tillage typesBased on straw returning, the soil bulk density were decreased with the turn over depth of the soil. With the decreasing of soil bulk density, the relevant soil porosity increased,which improved the soil pedality.3. Effects on soil chemical properties in different tillage typesSoil available nitrogen derceased after straw returning in the four types of tillage. The content of the total nitrogen was increased contrast with the basical soil. Also, the content of total nitrogen in rotary-tillage treatment was the largest,which in no-tillage treatment was the smallest.The content of available phosphorus and total phosphorus in the four treatments were all increased.The order was: no-tillage>rotary-tillage>shallow-tillage>deep-tilla ge.The content of soil rapidly available potassium and slowly available potassium of the four types tillage were all increased, and the content of slowly available potassium increased with depth.The content of soil organic matter was increased by straw returnning and different tillages. While the rotary-tillage treatment was the largest. The pH of four tillages were all decreased, and CEC of the four treatments were increased similarly with organic matter.4. Effects on soil biological properties in different tillage typesSoil nitrate reductase activities were decreased with the increasing of extent of turn-over soil,which were same as soil bulk density,and the order was : no-tillage>rot-ary-tillage>shallow-tillage>deep-tillage.Soil urease activities were changed little during the early growth stage of wheat under the four kinds tillage, they are in turn during wheat exuberant stage as following: no-tillage>rotary-tillage>shallow-tillage>deep-tillage.It was indicated that the soil enzyme activities relevant nitrogen transformtion affected with depth .Soil alkaline phosphatase and neutral phosphates activities were higher in alkaline soil, they were changed little during the whole growth stage of wheat and under the four kinds tillage.Acid phosphatase activities were changed significantily,it was improved drasticly during latter peroid of wheat. Acid phosphatase activities were changed with temperature.The dynamic change of soil microbial biomass carbon and nitrogen during the whole growth of wheat were as follow: increased at first and then decreased,with the mature of wheat,they were decreased again. soil microbial biomass carbon and nitrogen decreased with tilth depth under the four types tillage .5. Effects on soil physical properties in different rotationsSoil bulk density were changed with different rotations, soil bulk density in wheat/soybean and wheat/peanut treament were decreased greater than wheat/maize treament. 6. Effects on soil chemical properties in different rotationsThe available nitrogen of wheat/maize were decreased by 8.14 mg.kg-1,while that were increased of wheat/pean -ut and wheat/soybean treatment in the year of 2008.The total nitrogen of wheat/maize were decreased by 0.005%,while that were increased of wheat/pean -ut and wheat/soybean treatment in the year of 2008.The available phosphorus and total phosphorus in the three treatments were increased.There were significant differences between Wheat/maize and wheat/peanut treatment, and extremely significant differences between wheat/maize and wheat/peanut treatment.The content of rapdily available potassium and slowly available potassium in the three treatment were decreased in 2008. The changes of soil CEC were the same with soil organic matter, which were inceased in 2008.The pH in the three treatment were decreased in 2008, the extent of pH decreased in wheat/soybean treatment was the biggest.7. Effects on soil biological properities in different rotationsThere were different effects on soil enzyme activities under different rotations. The soil nitrate reductase and urease activities in wheat/maize treatment were higher than other two treatments.The trend of soil microbial biomass carbon and nitrogen under different rotations were similar with the growing period of the crops, but the content of soil microbial biomass carbon and microbial biomass nitrogen were different among the three kinds rotation, the order was: wheat/peanut > wheat/soybean> wheat/maize.