长期有机物循环对红壤稻田养分及水稻生长的影响

通过长期有机物循环的定位试验，研究了长期有机物循环利用对红壤稻田养分供应及水稻生长发育的影响，目的是了解长期有机物循环利用后土壤养分含量变化、水稻生长特性及两者的相关性。结果表明有机物循环明显提高了土壤有机质含量，并使土壤养分维持在一个相对较高的水平上。有机物循环处理的土壤有机质，全N、全P和全K及其有效部分的平均含量分别比无循环处理提高了445％、347％、175％、94％，特别是碱解N，速效P和速效K含量提高显著，有机物循环处理比无循环处理提高达469％、452％和347％。有机物循环利用提高了水稻分蘖数和叶面积指数，使水稻群体的透光率减少。有机物循环处理平均单叶净光合速率比无循环处理高68％，蒸腾作用比无循环处理高50％，最终表现为干物质积累量及稻谷产量的增加。对长期有机物循环利用后的红壤稻田养分指标与水稻生长指标进行逐步回归分析后发现，土壤中速效P及有机质含量的增加是促进水稻生长的主要因素.

EFFECTS OF LONG-TERM ORGANIC MATTER CIRCLING ON RED PADDY SOIL NUTRIENT AND RICE GROWTH

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.