长期施用化肥和稻草对红壤水稻土肥力和生产力持续性的影响

Effects of Long-Term Application of Fertilizer and Rice Straw on Soil Fertility and Sustainability of a Reddish Paddy Soil Productivity

【目的】研究长期施用氮(N)、磷(P)、钾(K)化肥和稻草(RS)对中国亚热带地区红壤水稻土肥力变化的趋势和水稻生产力可持续性的影响。【方法】利用1981年建立在湖南省望城县黄金乡第四纪红土红壤发育的水稻土(分类为普通简育水耕人为土)上的定位试验田,对氮、磷和钾化肥及其与稻草长期配合施用的5个处理的土壤肥力和生产力可持续性进行了评价。【结果】氮、磷和钾化肥与稻草长期配合施用能维持和提高红壤水稻土的生产力和土壤肥力;水稻获得了持续高产,土壤有机质、全氮、全磷、可矿化氮量均增加,速效磷和速效氮比试前土壤增加。长期施用氮、磷肥而不施钾肥的NP处理水稻产量、土壤氮、钾逐年降低,稻田系统生产力的可持续性和土壤肥力难以维持。稻草还田对水稻具有显著的增产作用,27年54季的稻草还田配合化肥处理的平均水稻产量比仅施化肥的NP和NPK处理分别增产12.2%和6.7%,稻草的增产作用还随着稻草还田时间的延长而逐年提高。【结论】稻草还田携入的钾与化学钾肥具有相同的营养功能,稻草可替代部分化学钾肥。

【Objective】 The effect of long-term application of nitrogen （N）,phosphate （P） and potassium （K） fertilizer and rice straw （RS） on change trends of soil fertility and productivity sustainability of double rice （Oryza Sativa L.） cropping system were investigated in a reddish paddy soil of subtropical climate region in China. 【Method】 This study evaluated the soil fertility and productivity sustainability in five treatments composed of N,P and K fertilizer and combined application of fertilizer with RS in a long-term experimental field established in 1981 designed to examine the effects of fertilization on soil properties and rice crop productivity of a reddish paddy soil （classified as typical stagnic Anthrosol） derived from parent materials of Quaternary red clay. 【Result】 Results showed that long-term balanced application of N,P and K fertilizers and in combination with RS could increase significantly soil organic matter （SOM）,total N （TN）,total P （TP）,potentially mineralizable N （PMN）,available P and K compared with their initial value in 1981. Rice yield,N and K content in soil were lowered year by year in NP treatment without K fertilizer,and productivity sustainability of rice crop and soil fertility could not be maintained. Rice straw returned into soil significantly increased rice yield. Average rice yield with 27 years rice straw-returned treatment （NP＋RS and NPK＋RS） were increased by 12.2% and 6.7%,respectively,compared with NP and NPK application alone. 【Conclusion】 Rice straw could partly replace chemical K fertilizer as the nutrient of K brought by rice straw had the same function as that of chemical K fertilizer.