优化施磷对华南酸性红壤区甜玉米产量、磷肥利用效率和碳排放的影响

Effects of optimal phosphorus application strategies on the yield,phosphorus use efficiency and carbon emission of sweet maize in acid red soil of South China

为优化华南酸性红壤区甜玉米减磷增效措施,分别在福建诏安和琅岐开展田间试验,研究不同施磷处理(对照,0kg/hm2;农户常规,化学磷肥135kg/hm2+有机肥6000kg/hm2,撒施;恒量监控,化学磷肥35kg/hm2,穴施;有机替代,化学磷肥17.5kg/hm2+有机肥434kg/hm2,穴施)对甜玉米产量、磷素累积量、磷肥利用效率和碳排放的影响。结果表明:1)恒量监控和有机替代处理的甜玉米产量、生物量和磷素累积量与农户常规处理之间无显著性差异。2)与农户常规处理相比,恒量监控和有机替代处理均可以提高甜玉米的磷肥偏生产力和磷肥回收利用率。3)恒量监控和有机替代处理的平均产投比分别较农户常规处理提高39.8%和36.5%,平均每kg产量的碳排放量较农户常规分别下降14.9%和13.2%。因此,恒量监控和有机替代处理可以满足甜玉米稳产需求,同时可以提高磷肥利用效率、增加收益和减少碳排放,是减磷增效的有效途径。

In order to optimize phosphorus(P)fertilizer application strategies of sweet maize for high efficiency and yield in acid red soil of South China,field experiments were conducted in Zhaoan and Langqi counties in Fujian Province.The effects of different P fertilization practices on sweet maize yield,P accumulation,P fertilizer use efficiency and carbon emission were investigated.Four treatments were control treatment(P2 O50 kg/hm2),farmer fertilizer practice(P2 O5135 kg/hm2 and organic matter 6000 kg/hm2 using broadcast application),optimal P fertilization practice based on P building-up and maintenance approach(P2 O535 kg/hm2 using spot application),and organic substitution treatment(P2 O517.5 kg/hm2 and organic matter 434 kg/hm2 using spot application).The results showed that:1)There were no significant differences between optimal P fertilization practice,organic substitution treatment and farmers’P fertilization practice on sweet maize yield,shoot biomass and P2 O5 accumulation.2)Optimal P fertilization practice and organic substitution treatment increased P fertilizer partial productivity and P fertilizer apparent recovery efficiency of sweet maize compared with farmers’P fertilization practice.3)Compared with farmers’P fertilization practice,the ratio of economic output to input under optimal P fertilization practice and organic substitution treatment increased by 39.5%and 36.2%,and carbon emissions per kilogram of production reduced by14.9%and 13.2%,respectively.Therefore,optimal P fertilization practice and organic substitution treatment can maintain sweet maize yield with increasing P fertilizer use efficiency and economic benefit as well as reducing carbon emission in red soil of high P concentration.