| Cinnamon soil,as primary soil type, is 2.861 million hectares in Shanxi Province, it covers around 28.8% cinnamon soil in China, and it is main cultivated soil in Shanxi Province.Fertilizers increase grain production effectively, especially for long-term fertilization.The unreasonable a application of nitrogennot causes waste of the resources, but also brings disadvantages to soil and environment.In this paper, two long-term positioning trials were conducted in cinnamon soil of dry land in Shanxi Province. One was application of nitrogen and phosphorus fertilizers and manure, and the other was application of different treatments. Corn yield, nitrogen loss condition, accumulation and distribution of nitric nitrogen in different soil profile and at different stage of corps under long-term different fertilizer were evaluated in order to find out some means which were suitable for dry-land corn in cinnamon soil of our country, were helpful for keeping high and stable yield of corn, and could reduce excessive nitrate nitrogen accumulation and leaching.The results showed that:1. The treatment of N120 kg/hm2, P2O5 37.5 kg/hm2, and manure 22500 kg/hm2, and of fertilization and straw returning by mulching in autumn were the best for getting higher yields with a relatively low investment, and less NO3--N accumulation in soil.2. Overall, reasonable application of fertilizer with nitrogen and with phosphorus or of fertilizer and manure could reduce nitrogen content besides keeping high yield. The utilization of apparent nitrogen was 62% at the treatment of N2P1M1, at which showed a low nitrogen surplus. With the increase rate of nitrogen application, apparent utilization efficiency of nitrogen fertilizer declined, and nitrogen surplus increased gradually.For different treatments, nitrogen surplus in soil was:straw returning by livestock digestion> straw returning directly> straw returning by mulching> no straw returning. A high level of nitrogen in soil surplus was found in straw returning by livestock digestion with a high risk of nitrate leaching.3.Long-term fertilization showed markable effect on NO3--N contration and distribution in soil from 1992-2013.There was a very low NO3--N content in soil in 1992, and it mainly accumulated in 100～300 cm depth of soil. In 2003, NO3--N distribution and accumulation in soil changed at all fertilization treatments. The more nitrogen applied, the higher residue of NO3--N in soil. Accumulation of NO3--N was in 100～300 cm depth of soil. The treatment of N2P1M1 showed a low NO3--N content and low risk of NO3--N leaching in the subsoil. The soil NO3--N accumulation could be reduced effectively in the treatment of direct straw returning and of straw returning by mulching, and the NO3--N accumulation in the treatment of straw returning by livestock increased obviously. The NO3--N contents were 695.72 kg/hm2 in 2003 and 1428.97 kg/hm2 in 2013 in 0～300 cm depth of soil in the treatment of fertilization in autumn+wet dung+straw returning by livestock digestion.4. The NO3--N content in soil changed at different stage of crops. NO3--N mainly concentrated in 0～20 cm depth of soil at early growth of crop in May,2013, reduced remarkably in 0～20 cm depth of soil and increased in 20～80 cm at the booming stage of crops in July. It raised in 100 ～300 cm soil depth considerably, which showed NO3--N obviously move downward after crop harvesting.5. Form the results, nitrogen application of 120 kg/hm2a could meet requirement of crop growth. Nitrogen surplus increased significantly when its application exceeded 120 kg/hm1. The treatmemnt of fertilization in autumn +straw returning by mulching could maintain soil nitrogen surplus at a relatively low level while guarantees a good crop yield. |
