Effects Of Conservation Tillage On Growth And Water Use Of Wheat-maize Rotaion

The studies were conducted on the effect of two practices,including tillage treatment(Plow tillage,No tillage,No tillage with straw mulch)and Rainfall(470mm,610 mm.750mm)on water use efficiency,soil physical and chemical properties,crop growth and yield. The main results were as fallow:The soil density in 0~40 cm soil depth of Plow tillage treatment were significantly lower than No tillage treatment and No tillage with straw mulch treatment, there were no significantly difference of soil density between No tillage and No tillage with straw mulch treatment in 10~40 cm depth. No tillage with straw mulch had significantly lower soil temperature in 0~20 cm depth during every growing stage of Winter Wheat- Summer Miaze rotation except for overwintering stage. No tillage had faster heating rate than Tillage treatment in crop seeding stage and mature stage because of sunshine can illuminate soil surface directly,the soil heat spreading rate to atmosphere of No tillage treatment to is lower than the rate of Plow tillage Treatment,the soil temperture of No tillage treatment rose higher than Plow tillage treatment. In high leaf area indexes stage, because Plow tillage treatment had lower density,the rate of heat transfer to soil under Plow tillage treatment was higher than No tillage treatment, air temperature transfer to surface soil caused soil temperature of Plow tillage increased faster than No tillage treatment. The soil water storage of No tillage with straw mulch were significantly higher than No tillage treatment and Plow tillage treatment, but the difference between soil water storage of No tillage treatment and Plow tillage treatment was closely related, the soil water storage of No tillage treatment is significantly higher than Plow tillage treatment under 470 mm rainfall and 610 mm rainfall, the soil water storage of No tillage treatment is significantly lower than Plow tillage treatment under 750 mm rainfall.The amount of soil total nitrogen and Soil total phosphorus in 0~20cm depth, soil microbial biomass carbon and soil microbial biomass nitrogen in 0~40cm depth of No tillage with mulch treatment were higher than No tillage treatment and Plow tillage treatment. Soil total potassium content of three treatments were no significantly difference.(2)The leaf area indexes, leaf area duration, SPAD value of ear leaf, dry matter accumulation of No tillage with mulch treatment were lower than No tillage and Plow tillage treatment under three rainfall. The leaf area indexes of Maize, leaf area duration and dry matter accumulation of No tillage treatment were significantly lower than plow tillage treatment under 470 mm rainfall and 610 mm rainfall, the tendency is opposite under 750 mm rainfall. Wheat tiller number, dry matter accumulation, plant height, mean leaf area indexes, leaf area duration of No tillage with mulch treatment were significantly higher than No tillage treatment and Plow tillage treatment, the above indexes of No tillage treatment was lower than Plow tillage treatment. The height of No tillage Wheat and SPAD Value of No tillage Wheat after flowering were higher than Plow tillage treatment under 470 mm rainfall and 610 mm rainfall, the height of No tillage Wheat and the SPAD Value form 21 d to 35 d after flowering were lower than Plow tillage treatment.(3)Maize yield, Wheat yield and yield component of No-tillage with mulch treatment were higher than No tillage treatment and Plow tillage treatment. The Grain number per spike of No tillage treatment were higher than Plow tillage treatment under 470 mm rainfall and 610 mm rainfall, The Grain number per spike of no tillage treatment were lower than Plow tillage treatment under 750 mm rainfall. The effective spike of No tillage Wheat were lower than Plow tillage Wheat under there rainfall. 1000-grain weight of No tillage Wheat was higher than Plow tillage treatment under 470 mm rainfall and 610 mm rainfall, 1000-grain weight of No tillage Wheat and grains per spike of No tillage Wheat were significantly lower than Plow tillage wheat under 750 mm rainfall.(4)The annual Evaportranspiration of No tillage with mulch in Wheat-Maize rotation were lowest,the yield and water use efficiency of No tillage with mulch were highest among three tillage treatments. The annual Evaportranspiration of No tillage treatment was lower than Plow tillage treatment, but water use efficiency of No tillage treatment was higher than plow tillage treatment under 470 mm rainfall. The annual Evaportranspiration of No tillage was lower than Plow tillage treatment, but there was no significantly difference of water use efficiency between No tillage treatment and Plow tillage treatment under 610 mm rainfall. The annual Evaportranspiration of No tillage was higher than Plow tillage treatment under 750 mm rainfall, but there was no significantly difference between water use efficiency of No tillage treatment and plow tillage treatment under 750 mm rainfall.