The Characteristics of Nitrogen Use Efficiency and Soil Nitrogen Supplying after Long-term Fertilization in Black Soil

The experiment was carried out to study the characteristics of nitrogen use efficiency and soil nitrogen supplying of lack soil in Hailun Agricultural Ecology Station,Chinese Academy of Sciences after long-term fertilization. The results showed that compared with control (no fertilizer application),applying fertilizer could increase the content of soil ammonia,soil nitrate,mineralizable N,plant N and soil productivity obviously; compared with single application of nitrogen fertilizer,chemical fertilizer amended with manure could increase the content of soil ammonia,soil nitrate,mineralizable N,plant N and soil productivity significantly. Moreover,with applying nitrogen fertilizer into the sample soils which were collected from long-term fertilization plot,we found that the highest efficiency of N was in no fertilizer soil,however,the lowest efficiency of nitrogen appeared in nitrogen fertilizer together with manure soil.