Effects Of Conservation Soil Tillage Systems On Soil Fertility And Grain Yield Of Summer Maize

The research began in the field in Yuying Village, Pengyao Township, XipingCounty, Zhumadian City, Henan Province in2007, and this study was conducted inJune and September2010in order to find a suitable integrated system in rain fed areaof southern Henan, A combination of field testing and laboratory analysis methodswere adopted. Eight treatments were from the combination of four-year intervalsubsoiling, three-year subsoiling followed by no-tillage, three-year no-tillage followedby subsoiling and four-year no-tillage with the straw mulching and clearance for fouryears. The effects of eight treatments on soil physical and chemical properties, soilorganic carbon, soil enzyme activities and growth and yield of summer maize werestudied. The main results are as follows:1. In the0-100cm soil layer, soil moisture content of straw mulching was morethan no-straw mulching, between different farming tillages,soil moisture con-tent insize for: three-year subsoiling followed by no-tillage, four-year subsoiling, three-yearno-tillage followed by subsoiling and four-year no-tillage.The bulk density duringseeding period was0.019g/cm~3lower than that during maturity. The bulk density ofstraw mulching was0.075g/cm~3lower than no-straw mulching; the bulk density wasdecreased as0.020g/cm~3by four-year subsoiling tillage compared with three-yearsubsoiling followed by no-tillage; the bulk density of three-year no-tillage followed bysubsoiling was0.025g/cm~3lower than four-years no-tillage.2. Straw mulching improved soil nitrogen, available phosphorus, potassiumcontent and organic carbon content; four continuous no-tillage improved mass fractionof N, P and K of the surface soil in0-5cm, three-year subsoiling followed by no-tillage,four-year subsoiling and three-year no-tillage followed by subsoiling increasedthe lower5-20cm of soil nitrogen, available phosphorus potassium content andorganic carbon, compared with the four continuous no-tillage. 3. Soil catalase, alkaline phosphatase, urease and invertase activities along withthe changes of the maize growing season showed significant regular changes, in maizegrowth stage of strong peak flowering, a variety of farming methods of enzymeactivity under the changing trends of the basic consistent, four kinds of soil enzymeactivity were higher in the topsoil, The wheat straw mulching treatment combined withcontinuous three-year subsoiling followed by no-tillage greatly increased the enzymeactivity than other treatments.The wheat straw mulching treatment combined withcontinuous three-year subsoiling followed by no-tillage greatly increased the enzymeactivity than other treatments.4. No-straw mulching increased maize seedling emergence, compared with strawmulching,three-year subsoiling followed by no-tillage and three-year no-tillagefollowed by subsoiling improved the leaf area index, higher dry matter productionbefore flowers and after flowering, late growth stage of corn chlorophyll content hasbeen higher than other treatments to improve the protective enzymes SOD, POD, CATactivity and MDA content has remained relatively low level, reducing the extent ofmembrane lipid peroxidation, slow down aging, late the formation of more grains perspike, and ultimately improved the yield.5. Straw and farming methods had significant effects on interaction of the spike,grain weight and yield of grains per spike, the effect of the economic coefficient wasnot significant. The yield was increased by10.68%with straw mulching treatmentcompared with no-straw mulching; the yield of three-year subsoiling followed by no-tillage was increased by2.60%compared with four-year subsoiling; three-year no-tillage followed by subsoiling was increased by4.21%compared with four-years no-tillage; the yield of three-year subsoiling followed by no-tillage with straw mulchingwas increased by23.32%compared with four-year no-tillage.