Effrct Of Combined Application Of Organic And Inorganic Fertilizers On Reduce Nitrogen Fertilizer Of Winter Wheat In Weibei Dryland

Wei Bei dryland is a typical dryland of the loess plateau. The average annual rainfall was 500-600 mm. With fertilization technology widespread application, due to the unreasonable fertilizer application, the soil fertility and fertilizer use efficiency declined significantly. Only suitable proportion in combined application of organic and inorganic fertilizers could improve nitrogen and water use efficiency. High amount of nitrogen fertilizer combine with organic manure significantly reduced the winter wheat yield, water and nitrogen use efficiency and increased the residual NO3-N.Therefore, in order to explore a suitable proportion in combined application of organic and inorganic fertilizers to local ecological conditions in Weibei dry-land,the author carried out field trials to investigate the effects of combination of different rates of nitrogen fertilizer(0,75,150,225,300 kg N/ha) with organic manure(pig manure 30t/ha)on winter wheat yield, water and nitrogen use efficiency, soil nutrients.The population quantity of the winter wheat increased firstly and decreased afterwards along with growth period. From the seeding to the reviving stage, the population quantity of the winter wheat increased rapidly, and reach maximum in the reviving stage, then gradually reduced. Applying inorganic fertilizer with organic manure increased the population quantity of the winter wheat significantly. Too high or too low N application rates were not conducive to growth and development of winter wheat. Applying inorganic fertilizer with organic manure can improve winter wheat yield, especially in the arid year. The yield of the winter wheat increased firstly and decreased afterwards along with the growth of N fertilizer application. The maximum of winter wheat yield was occur in the MN225 treatment, and increase 1.2%,12.7%,3.5% compare to the same N fertilizer application rates of inorganic fertilizers treatment(N225) in three years. Applying inorganic fertilizer with organic manure could obtain higher winter wheat yield under the condition of low N fertilizer application rates compare to the inorganic fertilizers treatment, especially in the arid year. Considering the yield, in the condition of using organic manure, the nitrogen fertilizer in 150kg/ha-N or more lower is appropriate to this region. Applying inorganic fertilizer with organic manure can improve winter wheat yield mainly because the application of manure could increase the spikes number. Different fertilization practices had no significant effect on grain number and 1000-kemelweight.Applying inorganic fertilizer with organic manure had higher soil water depletion than the inorganic fertilizers treatment. Applying manure could strengthen winter wheat utilization of the deep soil water, but the deep soil water deficit was nots allow to ignore. Only suitable proportion in combined application of organic and inorganic fertilizers could improve the water use efficiency. The maximum of winter wheat water use efficiency occur in the MN225 treatment.Applying inorganic fertilizer with organic manure significantly improved the absorption of N, P and K of winter wheat. When nitrogen fertilizer application rate was 150 or 225 kg N/hm2, winter wheat nitrogen, phosphorus and potassium uptake is significantly higher than the other treatments. After 3-year’s continuous cropping, the combined application of inorganic fertilizer with organic manure made the soil organic matter,total nitrogrn, available phosporus,available potassium increased by 18.8 %, 22.2%, 282.1 %, 15.1 %, respectively.High amount of nitrogen fertilizer combine with organic manure significantly reduced nitrogen use efficiency, and increased the residual NO3-N. Hence, considering the yield and environmental risks, in the condition of using organic manure, the nitrogen fertilizer in 150kg/ha-N or more lower is appropriate to this region.