Effect of long-term fertilization on total nitrogen storage in a brown soil

Soil nitrogen (N) is an important indicator of soil fertility, which is affected by natural factors and fertilization practices. The changes of N in 0-60cm layer of a brown soil in a long-term fertilizer location experiment (29 years) were studied. Results showed that soil total nitrogen (TN) and the C/N ratio significantly declined with depth. Different fertilizer treatments not only significantly affected TN contents and the C/N ratio in the topsoils, but also the soil total nitrogen storage in 0-60cm soil layer. The storage of soil total N followed the order: high level of organic manure treatment ＞low level of organic manure treatment ＞fertilizer treatment ＞check treatment ＞the formal soil (1979). Combine application inorganic fertilizers and high level of organic manure had the most significant impact on TN and the soil nitrogen storage. Although single application inorganic fertilizer could enhance the concentration, but less significance compared to combine application with organic fertilizer, indicating the changes of soil total nitrogen content closely related to the different fertilization. Manure plus mineral fertilizer increased the content of TN and TN storage, and was considered the best way for maintaining the soil fertility and sustainable agriculture.