基于太湖地区8 a的长期试验,应用常规化学分析法和数学统计方法,研究了不同施肥方式即单施化肥(NPK)、化肥配施稻麦全量秸秆还田(NPK+S)、无机肥配施鲜猪粪7.5 t.(hm2.a)-1(NPK+M7.5)及无机肥配施鲜猪粪15.0 t.(hm2.a)-1(NPK+M15)对稻麦轮作农田的作物产量、土壤各形态磷的累积及其潜在环境效应的影响.结果表明,在单施无机磷肥基础上,无论是秸秆全量还田还是配施不同量的猪粪,稻麦均没有显著增产;长期以常规无机磷肥用量配施猪粪,其土壤Olsen-P、Mehlich3-P、草酸盐磷(Pox)、CaCl2-P、水浸提磷(WEP)、总磷(TP)及土壤磷饱和度(degree of P saturation,DPS)等均显著增加,且配施猪粪量越大,各形态磷的累积量越大,土壤积累磷的环境风险越高;长期在常规无机磷肥用量基础上进行全量秸秆还田,与秸秆不还田处理相比,土壤各形态磷并无显著累积.综合考虑稻麦的产量效应、土壤磷库表观收支平衡、磷素长期累积的环境风险及经济效益等,在本研究区域目前的土壤环境条件下,常规磷肥施用量(45 kg·hm-2)基础上进行全量秸秆还田这一施肥方式是值得推荐的.
An 8-year field experiment was conducted in the Taihu Lake region of eastern China to investigate the effects of incorporation of straw and manure on the yield and phosphorus(P) accumulation in the paddy soil,and to evaluate the potential risk of P loss from soil to environment.The experiment had four fertilization treatments,i.e.,chemical fertilizers alone(NPK),chemical fertilizers plus rice/wheat straw(NPK+S),chemical fertilizers plus 7.5 t·(hm2·a)-1 wet pig manure(NPK+M7.5),and chemical fertilizers plus 15.0 t·(hm2·a)-1 wet pig manure(NPK+M15).Among the four treatments,no significant differences were observed in the yield of rice or wheat.Long-term application of chemical fertilizers plus pig manure significantly increased the soil total P,the degree of P saturation(DPS),and the concentration of extractable P forms,including Olsen-P,Mehlich 3 extractable P,CaCl2 extractable P,and water extractable P,which became a potential source of eutrophication in Taihu Lake.In contrast to chemical fertilizers plus pig manure,there were no significant differences in the concentrations of extractable P forms between the NPK+S and NPK treatments.We concludes that chemical fertilizers [P 45 kg·(hm2·a)-1] plus rice/wheat straw should be recommended in the paddy soil in the Taihu Lake region under the rice-wheat rotation system.