The Effect of Different Fertilization Treatments on Content Change of Different form Nitrogen in Black Soil

A pot experiment with spring wheat and black soil was conducted to study the dynamic changes and release characteristics of different form nitrogen in soil at different fertilization treatments. The results showed that organic nitrogen was the main form at crops growth season after chemical N fertilizer was applied and transformed through different approaches. The application of high N fertilizer increased the amount of soil organic N and microbial biomass nitrogen; compared with single application of chemical fertilizer, combination of chemical fertilizer and maize straw also increased the amount of soil organic N and microbial biomass nitrogen. Compared with the content of soil organic N, the content of soil inorganic N was very low, and the content of soil inorganic N in N2 and N2+maize straw treatments were higher than those of N1 and N1+maize straw treatments. Compared with single application of chemical fertilizer, combination of chemical fertilizer and maize straw reduced the accumulative amounts of soil inorganic N, indicating that application of high chemical N fertilizer increased its residual in soil inorganic N pool, combination application of chemical fertilizer and organic materials could enhance transformation of inorganic N to soil organic N, consequently avoided N losses due to the abundant accumulation of inorganic N in soil.