长期施肥条件下我国南方双季稻产量的变化趋势

Yield Trends of Double-Cropping Rice under Long-Term Fertilizations in Southern China

系统分析我国南方双季典型稻区福建白沙、江西进贤、江西南昌和湖南望城4个水稻长期施肥试验资料，研究化肥N、P、K（氮、磷、钾）的不同组合（NENK，NPK）、化肥配施有机肥（NPKM）及不施肥（CK）各处理水稻的产量差异、变化趋势。结果显示，不同施肥条件下各试验点上水稻产量差异大，试验期内各施肥处理较CK的总增产率分别为NPKM84．3％、NPK68．1％、NP42．9％和NK39．9％，其中NPKM总体上显著高于NPK。长期配施NPK或NPKM肥产量较稳定或呈上升趋势，尤其是晚稻，而仅施NK均呈下降或极显著下降趋势（周年变化幅度为-103～-201kg hm^-2），其他施肥处理晚稻产量相对稳定。不同试验点问年施磷量较高（52kg hm^-2）的南昌点产量相对稳定，而年施磷量较低（24kg hm^-2）的白沙点各处理均呈显著下降趋势。本试验条件下，施肥投入不足又特别是施磷肥量低或不施磷为早稻产量下降的主要驱动因素。合理施用NPK肥，配合有机肥，为推荐的施肥模式，为了使试验点双季稻产量稳定且不呈下降趋势，需年施纯磷50．0～63．9kg hm^-2，且适当偏重于早稻季。

Four long-term field experiments conducted in Baisha Fujian, Jinxian Jiangxi, Nanchang Jiangxi, and Wangcheng Hu-nan of Southern China, were selected to assess dynamic characteristics of double-cropping rice grain yield under different nutrient treatments. For each experiment, there were five treatments of chemical fertilizer NPK （NPK）, manure combifaed with chemical fertilizer NPK （NPKM）, chemical fertilizer NP （NP）, chemical fertilizer NK （NK）, and control （CK）. The results-showed that rice yield in the treatments of NPKM, NPK, NP, and NK increased by 84.3%, 68.1%, 42.9%, and 39.9%, respectively on average compared with CK, and was remarkably higher in the NPKM than in the NPK treatment. Rice yield change as a whole showed increasing or stable trend for the NPKM and NPK treatments, especially for late-rice. Rice yield showed a decreasing trend in the NK treatment, but stable in other treatments. The early-rice was declined with lasting planting years than the late-rice. The sig- nificantly positive correlations were found between the yield trends and phosphorus application rate across the sites. There were a relative stable yield trend in Nanchang due to the higher phosphorus application per year （52 kg ha^-1）, and the negative trends in Baisa due to the low phosphorus application per year （24 kg ha^-1）. The deficiency of phosphorus fertilizer makes rice yield de-creasing. The yield-declining trends were observed in rice especially in early-rice with no fertilizer or chemical fertilizers alone. The results suggest that manure application combined with chemical NPK fertilizers should be encouraged for increasing yield and sustainability Phosphorus should be appropriately applied per year at 50.0-63.9 kg ha^-1, especially for early-rice.