长期不同施肥措施下红壤稻田的养分循环与平衡

Nutrient Cycling and Balance of Paddy Fields with Different Long-term Fertilization Management in Red Soil Region

红壤丘陵地区荒地或旱地开垦为水田不仅可以治理土壤侵蚀,而且能增加土壤肥力,提高农田生产力。本文分析了长期不同施肥措施下垦自红壤荒地的稻田2004—2007年的养分循环和平衡特征及变化。结果表明:不同垦殖年限施肥措施对水稻产量的影响基本不变,都是NPK+有机质循环(8589kg/hm2)>NPK(7804kg/hm2)>N+有机质循环(6626kg/hm2)>有机质循环(4525kg/hm2)>无肥区(2707kg/hm2),且随着垦殖年限增加,不同施肥措施间产量差异有增大趋势。P是中低肥力红壤稻田的主要限制因子,不施P肥对早稻产量的影响高于晚稻。有机物循环可以提高系统养分的再循环率,循环及循环配施化肥处理的养分都有盈余,单施化肥则会导致养分亏缺。高产稻田生态系统N素输入主要依靠化学N肥,有机肥是重要的P素资源,秸秆还田对于稻田K平衡有重要作用。

Reclamation of wasteland or dryland into paddy field in upland of red soil region can not only mitigate soil erosion, but also increase soil fertility and promote productivity of cropland. In this paper, nutrient cycling and balance characteristics from 2004 to 2007 were analyzed. Results showed that the rice yields of different treatment were in an order ofNPK ＋ organic cycling （8589 kg/hm^2） 〉 NPK （8589 kg/hm^2） 〉 N ＋ organic cycling （6626 kg/hm^2） 〉 organic cycling （4525 kg/hm^2） 〉 no fertilizer （2707 kg/hm^2）, and the differences among treatments increased with rice cultivation. Phosphorus was one of the most important limiting factors of paddy field with low or medium fertility level in red soil region. Phosphorus fertilizer affected yields of early rice more than that of late rice. Organic cycling promoted recycling ratio of organic nutrients. Treatments of organic cycling combined with or without chemical fertilizers＇ nutrients supply were surplus, and treatments of only supplied with chemical fertilizers resulted in one or more nutrients＇ deficits. Chemical N fertilizer is the main nitrogen input and organic fertilizers are important phosphorus resource. Rice straw plays an important role in potassium balance of paddy field.