长期施用有机肥对水稻产量和氮磷养分利用效率的影响

以长三角地区典型土壤类型青紫泥为背景土壤,研究连续7年有机肥不同施用量和化肥减量条件下水稻产量、氮磷吸收累积特性和氮磷利用效率,并对影响水稻氮磷吸收利用效率的原因进行分析。结果表明,与纯化肥处理相比,施用有机肥处理在不同程度上增加了水稻产量,其中以处理C4(30 t·hm~(-2)有机肥+1/2常量化肥)增加比例最大,为5.67%。当有机肥单施用量达60 t·hm~(-2)时,水稻产量比纯化肥处理增加5.56%,地上部氮磷累积均高于其它各处理,其中,氮累积尤为明显,增加比例为16.5%~25.4%。有机肥不同用量配合化肥减量施用时水稻地上部氮磷转运量、生理利用效率与纯化肥处理间无明显差异。然而,当单施有机肥用量达60 t·hm~(-2)时,氮转运量明显增加,生理利用效率明显降低,磷生理利用效率亦有所降低,但不如氮明显。水稻氮磷生理利用效率降低的主要原因是长期大量施用有机肥使土壤养分含量增加特别明显,可能超过利于水稻利用的浓度范围。另外,土壤矿质元素铵态氮在水稻生长过程中含量过高也与之紧密相关。

Effect of long term organic fertilizers application on rice yield,nitrogen and phosphorus use efficiency

A continuous seven years of field experiment was conducted on purple clay-based paddy soil to study rice yield and characteristics of nitrogen and phosphorus in rice plant under condition of different amounts of organic fertilizers and chemical fertilizer reduction application.Meanwhile,the factors affecting nitrogen and phosphorus use efficiencies in rice plant were analyzed.The results showed treatments with organic fertilizer application increased rice yield in various degrees compared with treatment with chemical fertilizer use only,of which treatment with 30 t · hm-2 organic fertilizer and 1/2 chemical fertilizer application had the highest rice yield,which was 5.67％ higher than treatment with chemical fertilizer use only.When organic fertilizer application rate reached 60 t · hm-2,rice yield was 5.56％ higher than that of chemical fertilizer use only,but accumulated highest nitrogen and phosphorus in aboveground part of rice in all treatments,especially for nitrogen with 16.5％ ～ 25.4％ higher than other treatments.There were no significant differences in nitrogen and phosphorus translocation amounts and physiological use efficiencies between the treatments with organic fertilizer and chemical fertilizer use together and the treatment with chemical fertilizer use only.When organic fertilizer application rate reached 60 t · hm-2,nitrogen translocation was raised obviously,but nitrogen physiological use efficiency was reduced significantly.Phosphorus in rice showed the same performance,although,less obvious than nitrogen.The reasons were soil nutrient contents increased very significantly with huge application of organic fertilizer,which probably were too much for rice to use.and ammonium nitrogen content in soil was too high during rice growth stage.