Effects Of Green Manure And Nitrogen Rate On Wheat Growth And Soil Property In Dryland

The demand of food is increasingly serious while the population is increasing and arableland is dropping. It has been an arduous task to improve soil fertility and enhance crop yields.Water and feitilizer are critical factors in crop production. It is of importance to make full useof rainfall and apply fertilizer in the proper way.A field experiment was conducted to studythe dynamics of dry matter and nutrient accumulation of three leguminous greenmanure-Soybean, Mungbean and Huai bean, and the effects of leguminous green manure andapplication of nitrogen fertilizer on the growth and yield of winter wheat and soil propertywith summer fallow as control. The aim was to study to determine the best green manurespecies with the optimal nitrogen fertilizer rate and the best termination time, which wasbeneficial to the agricultural sustainable development in Loess Plateau. The main results wereas follows:1. From sowing to incorporation, Dynamics of dry matter and nutrient accumulation ofHuai bean and Mungbean were shaped in S curves while those of soybean showedexponential growth. Huai bean and soybean had significantly greater dry matter and nutrientaccumulation than Mungbean before incorporation. Huai bean was the best species as summershort-term leguminous green manure and the best termination time was about full-bloomstage.2. Mungbean had reduced winter wheat seedling number compared to fallow treatment.Incorporation of leguminous green manure had improved wheat yield15.5%²9.6%andnutrient accumulation of nitrogen, phosphorus and potassium. Green manure increased WUE.3. Application of nitrogen fertilizer had increased all stem number in spring. In fallowtreatment, Application of nitrogen fertilizer increased wheat yield and water use efficiency.However, in green manure treatments, application of nitrogen fertilizer had no significanteffect on wheat yield or WUE, but decreased NUE.4. Incorporation three kinds of leguminous green manure enhanced soil nitratenitrogen accumulation in the depth of0²00cm by65.5kg N hm^-2320.7kg N hm^-2beforeharvesting wheat. After harvesting wheat, soil organic matter, active organic matter, totalnitrogen were also improved by8.0%¹4.7%,10.9%¹4.5%and10.8¹3.7%respectively in the depth of0²0cm; Soil available P was significantly increased by9.9%¹2.9%under Huaibean and Soybean. Planting green manure consumed more soil water compared with control,while enhanced water use efficiency.5. Soil respiration rate under different treatments all declined with time going by.Incorporation green manure significantly increased soil respiration rate. Soil temperature inthe depth of10cm accounted for66.6⁸4.3%of soil respiration rate. However, soil water in0¹0depth only accounted for24.2%²7.7%in green manure treatments and almost had noeffcet on soil respiration rate in control.