中文摘要：

【目的】研究高产水稻土有机碳和养分含量变化状况，为水稻土的定向培肥和持续利用提供科学参考。【方法】通过田间采样分析并比较第二次土壤普查的背景资料，研究江西省余江县高产水稻土有机碳和养分的含量状况及其近20余年来的变化情况，并分析其环境意义。【结果】江西省余江县高产水稻土表层0～10cm的有机碳、全氮和速效磷含量分别为（20．2±3．88）g．kg^-1、（2．09±0．55）g．kg^-1、（42．7±32．7）mg·kg^-1，均达到非常丰富的水平。近20余年来土壤有机碳库基本保持稳定、处于平衡状态，但全氮和速效磷含量显著增加，而速效钾含量变化不明显。高产水稻土表层0～10cm的磷固定量和固定率分别为（142．7±41．1）mg·kg^-1和（36．2±10．4）％，CEC为（7．93±1．32）cmol·kg^-1，并不比一般水稻土和旱地红壤高。这使通过施肥进入土壤的磷活动性增加，以致更易进入水体，可能是区域水体富营养化的主因。【结论】经过长期的耕作培肥，高产水稻土的有机质和速效磷含量均达到非常丰富的水平，有机碳库基本处于平衡状态，但磷的固定量并不高。由于该类型土壤的固钾能力较弱，高产水稻土的速效钾含量并不丰富，应当重视钾库的平衡保持和提高。

英文摘要：

[ Objective ] Studies on changes in organic carbon and nutrient contents of the highly productive paddy soils would be scientifically beneficial to the directional management and sustainable utilization of paddy soils. [Method] The contents of organic carbon and nutrients and their changes in the last over 20 years in the highly productive paddy soils as related to the environment~al significance were investigated by field sampling and comparison with the corresponding values in the Second Soil Survey in Yujiang County of Jinagxi Province. [Result]Results showed that 0-10 cm depth highly productive paddy soils in Yujiang County of Jiangxi Province contained organic carbon content of （20.2±3.88） g.kg^-1, total N （2.09±0.55） g.kg^-1, available phosphorus （42.7±32.7） mg.kg^-1, respectively, all were at the very rich level. In the last over 20 years, the organic carbon pool of the highly productive paddy soils remained a stable state, total N and available P increased significantly, while available K changed little. The amount and percentage of P immobilized in 0-10 cm highly productive paddy soils were （142.7±41.1） mg.kg^-1 and （36.2±10.4）% and of added P CEC was （7.93 ±1.32） cmol.kg^-1, being not higher than the mean value of paddy soils and that in upland red soils. It indicated that fertilizer P in highly productive paddy soils would be a high mobility and easily moved to water, being a main source of nutrient causing eutrophication. [Conclusion] For a long-term rice cultivation and fertilization, the highly productive paddy soils were very rich levels of organic matter and available P, and a steady state of organic carbon pool, while amount of P immobilized was not high. Because of a weak K-fixing capacity, the available K content was not rich in highly productive paddy soils, suggesting that attention should be paid to the balance and increase of soil K pool.