长期施肥红壤稻田肥力与产量的相关性及县域验证

Correlation of red paddy soil fertility with rice yield under long-term fertilization and county verification

【目的】土壤肥力是水稻生产可持续发展的基础资源,研究长期施肥下红壤稻田土壤肥力变化特征以及土壤肥力质量指数(SFI)和水稻产量之间的相关性,以期科学指导红壤稻田土壤培肥和评估区域水稻产量。【方法】本研究基于1982年开始的红壤稻田有机无机肥配施长期定位试验,采用模糊评判法计算不同施肥处理的SFI,建立SFI和水稻产量之间的拟合方程,并结合典型县域数据对拟合方程进行验证。【结果】经过30年的培肥,M(有机肥)、NKM(氮钾肥+有机肥)、NPM(氮磷肥+有机肥)、PKM(磷钾肥+有机肥)、NPKM(氮磷钾肥+有机肥)、NPK(氮磷钾肥)处理的SFI随施肥年限延长均呈缓慢线性增长趋势,年均增长0.0035~0.0136,而不施肥对照的SFI逐年下降。PKM和NPKM处理的年均SFI最高,比CK处理分别增加了70.6%和68.4%。5个施有机肥处理的年均SFI均高于单施化肥的NPK处理。线性拟合结果发现,1984、1988、1994、1998、2004、2008、2012年等7个年份的年均SFI与年均水稻绝对产量、相对产量呈显著线性正相关关系(P<0.05),相关系数分别为0.708、0.683。县域尺度的验证结果表明,基于SFI预测的水稻绝对产量、相对产量与实际的绝对产量和相对产量(RRMSE均小于25%)均高度相符。【结论】有机肥的投入是红壤稻田提高土壤肥力的有效措施,在红壤丘陵双季稻区,SFI和水稻产量之间存在显著的线性正相关关系,且SFI和水稻产量尚有一定的提升潜力。通过SFI和水稻产量的关系模型预测评估该稻区县域的水稻产量是可行的。

【Objectives】Soil fertility is the fundamental resource for sustainable development of rice production.We researched the variation feature of red paddy soil fertility under long-term fertilization,specified the correlation between soil fertility index(SFI)and rice yield,in order to provide a useful tool for the quantitative improvement and evaluation of soil fertility.【Methods】This study was based on a long-term experiment of red paddy soil started in 1982.The SFIs of different treatments were calculated by Fuzzy method.The fitting equation between SFI and rice yield was established and verified in a county scale.【Results】After 30 years of fertilization,the SFI increased slowly and linearly with the fertilization years in all the treatments except no fertilizer control,and the annual increases of SFI were in range of 0.0035–0.0136.The annual average SFI of five manure containing treatments were all higher than that of the NPK treatment,and those in PKM and NPKM were 70.6%and 68.4%higher than that in CK.There was a significant linear positive correlation between the average SFI and the annual average absolute and relative rice yields in 1984,1988,1994,1998,2004,2008,and 2012(P<0.05),and the correlation coefficients were as high as 0.708,0.683,respectively.The verification results based on SFI in the county scale showed the high consistency between the predicted and the measured absolute and relative rice yields,with the RRMSE both less than 25%.【Conclusions】Input of organic fertilizer effectively improves soil fertility in red paddy soil.The rice yield is significantly correlated with SFI in hilly red soil area,and SFI and rice yield still have some potential to improve.The rice yield in county scale could be predicted and evaluated by the relational model between SFI and rice yield.