稻田系统养分循环利用对土壤肥力和可持续生产力的影响

Effects of Nutrient Recycling on Soil Fertility and Sustainable Rice Production

基于12a田间定位试验结果,研究了在不同化肥配施条件下,有机养分循环利用对亚热带红壤稻田生产力和土壤肥力的影响。结果表明:①施用化肥是实现水稻高产的必要条件。在连续不施肥情况下,水稻产量维持在5.6t·hm-2的水平,投入化肥N(229kg·hm-2)、N-P(39kg·hm-2)和N-P-K(162kg·hm-2)之后,产量分别提高到了6.6、7.9和9.0t·hm-2。农田系统有机养分循环利用能进一步提高水稻产量,但产量增益随NPK配施程度提高而降低。②在不施肥或只施N肥的情况下,有机物循环利用能显著降低水稻产量的年际变异系数,而在NP或NPK配施基础上的有机物循环利用则不能显著提高水稻的稳产性能,说明适量和平衡地提供水稻所需的营养元素是水稻稳产的物质基础,至于这些养分是来自化肥或有机肥源并不重要。红壤稻田早稻的稳产性受施肥模式的影响较大,施磷肥是降低早稻产量波动、提高稳产性能的最重要条件。③连续12a不施肥对土壤有机质含量没有显著影响,施化肥NPK处理的土壤有机质含量呈现出不稳定的上升趋势,而有机物循环利用能显著提高土壤有机质含量和土壤养分的生物有效性。通过有机物养分资源的循环利用,可有效降低当前稻田化肥的高投入水平,减轻环境污染压力,实现农田生态系统生产力的高效可持续发展。

Based on a twelve- year field experiment, the effects of organic nutrient recycling use on soil fertility and sustainable rice production under various formulas of chemical fertilizer NPK application were studied in the double- rice cropping region of Subtropical China. The main results were as follows: (1) It was essential to apply chemical fertilizer for high yield of rice production, and the rice yield kept around 5.6 t· hm- 2 under no fertilizer application, while with applying fertilizer N (229 kg· hm- 2), N- P (39 kg· hm- 2), and N- P- K (162 kg· hm- 2), the yield raised by 6.6, 7.9 and 9.0 t· hm- 2, respectively. Organic nutrient recycling use could increase rice yield further, but the yielding benefit reduced with the increase of NPK combinative application; (2) Under no fertilizer application or applying N alone, the coefficients of annual variation of grain yield significantly reduced with the recycling of organic nutrient, which showed no further reduces under the application of NP or NPK, i.e, the stability of rice yield did not significantly improve with the application of NP or NPK.These implied that it was essential to use fertilizers with optimum application rate and balanced nutrients of NPK for a high and stable rice yield, no matter whether the nutrients came from organic manure or inorganic fertilizer resources. The fertilization systems affected the yield stability of early rice stronger than that of later rice in the experiment and application of fertilizer P was most important for the early rice to gain a high- and- stable grain yield; (3) Little declining of soil organic matter (SOM) content was found with no fertilizer application for continuly 12 years, while SOM content increased unstably with chemical N, NP, and NPK application. The recycling use of organic nutrients significantly increased SOM content and further improved the bio- availability of soil NPK nutrients. Moreover, through recycling use of the organic nutrients in the field system, the high input rate of chemical fertilizers could be effectively reduced without reducing grain yield, and, therefore, the environmental pollution stresses alleviated and the high efficient and sustainable rice production were realized.