Effect of long-term fertilization on crop yield and soil fertility in the high yield area of plain at the foot of Yanshan

A 8 years long term experiment was conducted on the high yield area of plain at the foot of Yanshan mountain. The results showed that the cinnamon soil is characterized by low storage and transformation potentiality of nutrition. Organic manure combined with chemical fertilizer remarkably raised the content of soil organic matter and total and available nutrients; improved soil organic inorganic complex and characteristics of humus, soil enzyme activity, soil moisture and physical characters ; and also increased crop yield compared with application of fertilizers. Long term application of chemical fertilizer alone, the contents of soil organic matter and total N were tended to decline, and poor characteristics of humus. Combined with equal rates of chemical fertilizer, the effects of different organic manure on soil fertility and crop yield was no significant.