长期有机无机肥配施对水稻产量及土壤有效养分影响

利用中国农业科学院红壤实验站开始于1982年的水稻长期定位试验,研究长期有机无机肥配施对水稻产量及土壤速效氮、磷、钾含量的动态变化(1982—2011年)特征。29年研究结果表明:长期有机无机肥配施(NPKM)能提高水稻产量,培肥地力。长期施用化肥(NPK)导致水稻产量降低。稻谷产量随着施肥量的增加而增加。在等氮投入情况下,增施化学磷肥的增产效应要高于化学钾肥,且早稻表现尤为明显;长期单施有机肥和单施化肥对稻谷产量的影响没有显著差异。随着施肥时间的延长,各处理水稻产量差异越显著。各施肥处理土壤碱解氮增加速率表现为慢-快-慢三个阶段,有机肥的施用相较单施化肥,能够显著提高土壤碱解氮含量(p0.05)。土壤有效磷的累积主要与化学磷肥的施用有关,各施肥处理土壤有效磷历年平均含量变化趋势为:NPKM、NPM、PKMNPKM、NKM(p0.01);土壤速效钾以有机肥和化学钾肥配施的处理(NPKM、NKM、PKM)增加最快,单施化学肥料的处理(NPK)增加最慢。随着氮、磷施用量的增加,土壤中氮、磷素出现盈余,但NPKM处理相比其他处理能够有效降低盈余量;各处理土壤中钾素均表现为亏缺状态,红壤性水稻田至少每年应补充投入钾素200 kg hm-2才能基本维持土壤钾素平衡。

Effects of long-term combined application of organic and chemical fertilizers on rice yield and soil available nutrients

A long-term fertilization field experiment on rice has been going on since 1982 in the Red Soil Experiment Station of CAAS to investigate effects of combined application of organic and chemical fertilizers on crop yield and contents of soil available nitrogen, phosphorus and potassium. Results show that higher fertilization rate raised crop yield. In treatments the same in N application rate, amendment of phosphate fertilizer was higher than amendment of potash fertilizer, in yield-raising effect and it was particularly obvious with early rice. No significant difference was observed between treatments receiving for long organic fertilizer only and chemical fertilizer only in yield-raising effect. With the experiment going on and on, differences between treatments got more and more significant. In all the treatments, alkalysable-N increasing rates showed a similar trend, low-high-low. Organic fertilizer was better than chemical fertilizer in raising alkalysable-N content (p<0.05). Accumulation of soil available phosphorus was mainly related to application of chemical phosphate fertilizer. In terms of the mean content of soil available P of the years, the treatments displayed an order of NPKM, NPM and PKM > NPK > M and NKM (p<0.01). Soil available K increased the fastest in Treatments NPKM, NKM and PKM and the slowest in Treatment NPK. With increased N and P fertilizers application rate, surplus of nitrogen and phosphorus appeared in soil. However, Treatment NPKM was better than all the others in mitigating the surplus. Potassium deficit was observed in all the treatments, suggesting that to maintain the basic balance of soil potassium, at least 200 kg hm-2 of K2O should be supplemented in red soil paddy fields annually.