Abstract:

To investigate the change of nutrient content in red paddy soil,the characteristics of rice growth and the relationship between soil nutrient and rice growth,the effects of longterm organic matter circling on soil nutrient and rice growth were studied in a longterm experimental field.The results showed that after longterm organic matter circling,the content of organic matter in paddy soil obviously increased,and the nutrient content was maintained at higher level compared with no organic matter circling treatments.The average content of soil organic matter (SOM),total N,P and K of organic matter circling treatments were 445％,346％,175％and 94％ higher than that of no organic matter circling treatments respectively.The average content of available N,P and K were 469％,452％ and 347％ higher respectively.The number under tillers and leaf area index increased and the canopy light transmission rate decreased with longterm organic matter circling.The net leaf photosynthetic rate and transpiration of rice under organic matter circling treatments also increased 68% and 50% respectively compared to no organic matter circling treatments.And the dry matter accumulation of overground parts and yield of rice of organic matter circling treatments also increased because of the improvement of canopy ecophysiological properties of rice.By using the method of stepwise regression analysis,the content of soil nutrient and the characteristics of rice growth were studied.It is indicated that the increase of available P and the SOM in red paddy soil were the main factors improving the growth of rice after longterm organic matter circling.

Key words: organic matter circling, red paddy soil, soil organic matter, available P, rice growth