长期和短期减施磷肥对华南双季稻产量与磷肥利用的影响

通过短期和长期试验相结合,研究减施磷肥对水稻产量和磷肥利用的影响。短期试验设置常规基施磷肥（P1）、磷肥减半基施（P2）和磷肥减半且基肥和穗肥各50%施用（P3）3个处理,以常规稻粤晶丝苗2号和杂交稻晶两优华占为供试材料,进行早晚两季试验;长期定位试验包含不施磷（M0）和常规施磷（M1）2个处理,采用9年18季试验数据。短期试验结果表明,磷肥减施对水稻产量、干物质积累量与转运、磷素积累量与利用等性状指标均无显著影响。P1、P2和P3处理间土壤总磷和可溶性磷含量均无显著差异,并且田面水总磷和可溶性磷含量在全生育期内无显著差异。P1、P2和P3处理的磷素盈亏率分别为8.7%、-35.3%和-31.8%,P1处理可达到土壤磷素表观平衡。长期定位试验结果表明,M0处理的产量随种植季节数增加而下降,3年6季内M0与M1处理产量相当。根据目前稻田土壤磷含量情况,在生产上3年内磷肥减半施用,既不影响水稻产量,又可降低稻田磷素损失风险,是兼顾产量和环保的技术方案。

Effects of Long- and Short-Term Reduction of Phosphorus Input on Yield and Phosphorus Utilization of Double Cropping Rice in South China

Short-term and long-term experiments were conducted to determine the effects of phosphorus (P) fertilizer reduction on rice yield and phosphorus utilization. In the short-term experiment, three treatments, including normal P application (P1), half-dosage P application as basal dressing (P2), half-dosage P application with 50% as basal dressing and 50% as panicle fertilizer (P3), were established in an early and a late cropping season, conventional rice Yuejingsimiao 2 and hybrid rice Jingliangyouhuazhan were used as materials. In the long-term experiment, two treatments of no P application (M0) and normal P application (M1) were set up for nine consecutive years (comprising 18 seasons). Results from the short-term experiment indicated that two P reduction had no significant effect on grain yield, accumulation and translocation of dry matter, P accumulation and utilization. Among three treatments, no significant difference existed in the total and soluble P contents in the soil or in surface water. The P surplus and deficit rate were 8.7%, -35.3% and -31.8% for P1, P2 and P3 treatments, with P1 treatment achieving P apparent balance in the soil. In the long-term experiment, the relative yield under M0 treatment displayed a gradual declining trend across cropping seasons. However, the yields were comparable between two treatments in the six first seasons of three years. It could be concluded that short-term P reduction for three years would do no harm to grain yield and could reduce P loss from paddy soil in these fields with low to medium level of P content. Basal dressing of P fertilizer with half dosage would be better for achieving benefits in both grain yield and environmental protection.