Research On The Feedback Mechanism Of Soil Microbial For Nitrogen Fertilizer Under The Condition Of Water-saving In Irrigation Salinization Irrigation District

Inner Mongolia Hetao irrigation district as the essence of important agricultural areas in China. Fertilizer showed a trend of increase year by year in the process of agricultural production. Meanwhile, the irrigation area faced with the policy of Yellow River water. Farmland environment, the Yellow River water pollution, soil salinization and water shortage will be the important factors of restricting agricultural sustainable development in the region. Developing research of feedback mechanism of soil microbial properties for nitrogen fertilizer under the water saving in salinization irrigation area is the requirement of promotion of modern agriculture and improvement of agricultural cleaner production level, and it is an important measure for irrigation area of ecological environment security and water security in the Yellow River. This paper revealed feedback mechanism of soil microbial under different nitrogen levels through field experiment, and raised a suitable nitrogen rate of salinization water-saving condition from the perspective of microbial. The results could provide the beneficial biological parameters and indexes to reduce nitrogen fertilizer, improve soil fertility and quality, reduce agricultural non-point source pollution and quantitative nitrogen in agricultural production.The main conclusions are as follows:（1） The soil nutrient, microorganism quantity, biomass presented different trends with the development of growth period. But under the suitable phosphorus content, Nutrients and microbial in the soih crop yield showed the tendency of increase after the first reduce with the increase of nitrogen levels. In N2, they were in peak and increased the effect of the most significant. When nitrogen is N3, they showed a downward trend.（2） The correlation of N application rate and wheat/corn, nutrients microbes in the soil were significantly related, individual reached extremely significant level. Between the nitrogen treatment、nutrients and microbial in the soil and crop yield could build a secondary index relationship. The index model simulation results showed that a suitable dosage of fertilizer could effectively promote the increase of the soil nutrients, microorganisms and crop yield, excessive fertilization was bad for the increase of soil nutrient fertilizer and yield, microbial growth and reproduction.（3） Through production and the related factors affecting the interactions and path analysis, showed that effect on wheat yield larger was available nitrogen, fungi and microbial biomass nitrogen, effect on corn yield larger was actinomycetes, microbial biomass carbon, available nitrogen. And yield increased with these factors increased levels, and proposed that the appropriate nitrogen content of wheat was 203.56 kg· hm^-2, the appropriate nitrogen content of corn was 280.11kg·hm^-2.