Effects Of Different Green Manure And Phosphate Fertilizer Application On Soil Fertility,Winter Wheat Growth And Fertilizer Reduction

In recent 40 years,application of chemical fertilizer played an important role in increasing crop production and made a great contribution to food security around the word.But with the rates of chemical fertilizer increasing,there appeared a series of environmental problems,such as soil degradation and water pollution.Our field experiment was conducted to evaluate the effects of planting different green manure（GM）（black bean and rapeseed）instead of summer fallow and phosphate（P）fertilizer rates applied to wheat（0,40,80,120,160 kg P₂O₅/ha）on soil fertility and winter wheat growth,and to provide theoretical and scientific methods to increasing soil fertility and decrease phosphate fertilizer application in dryland.The main results are as follows:（1）Planting rapeseed as GM in summer fallow period significantly increased the tillers number per plant in winter and the spikes number per unit area of wheat at harvest by 21.4%and 14%,respectively,and had the potentiality to increase the yield of winter wheat.Planting black beans as GM crop would have the negative effects on winter wheat yield.（2）Planting the GM crops during the summer fallow period decreased the P fertilizer rates when achieve the highest grain yield.The P fertilizer rates with the highest yield under the black bean and rapeseed treatments were 130 kg P₂O₅/ha and 153 kg P₂O₅/ha,respectively.Planting the rapeseed as GM could reduce the P fertilizer rates by 72%.（3）Planting rapeseed as GM increased the soil available K content after GM harvest.Besides,the soil available P content in the rapeseed treatment was increased before wheat sowing.Planting black bean as GM increased the nitrate-N content after wheat harvest.（4）The dry matter decomposition and nutrient release rate of above-ground in both of black bean and rapeseed were higher than those of roots.Besides,rapeseed decomposed faster than black bean either in the aboveground parts or in the belowground ones.In addition,the release rate of K was the highest,and the release rate of C,N and P were similar throughout the study.In general,Planting rapeseed as GM in dryland during summer fallow period could increase the tillers number and Spikes number of wheat,and would reduce the P fertilizer rates before wheat sowing.Which would provide theoretical basis and data for the study of increasing soil fertility and wheat yield and decreasing P fertilizer rates in dry land.