缓释复合肥减钾施用对菜地土壤微生物效应研究

Effects of Potash Reductions with Slow Release Fertilizer on Rhizosphere Soil Microbes of Vegetable Fields

在我国钾肥主要依赖进口的背景下,利用缓控释技术减钾施用对农业可持续发展具有重要意义.在高氮钾和低氮钾紫色土试验点(铜梁和北碚试验点)设置缓释复合肥减钾10%和30%(SRF1和SRF2),观察对3种叶类蔬菜(白菜、瓢儿白和生菜)土壤微生物的影响.结果表明,2个试验点低氮钾土壤的微生物量明显高于高氮钾土壤.高氮钾水平不同叶菜土壤细菌、放线菌、真菌以瓢儿白土壤含量最高.SRF1较CF(化肥)显著增加高氮钾水平下白菜、瓢儿白、生菜土壤细菌,增幅分别为11.5%,27.7%,22.2%.低氮钾水平生菜土壤放线菌SRF1较CF显著增加18.0%,较CCF(普通复合肥)显著增加16.4%.高氮钾水平SRF1白菜土壤真菌显著高于CF,增幅分别为13.4%和12.9%.高氮钾水平白菜、瓢儿白、生菜土壤革兰氏阳性菌和革兰氏阴性菌含量以缓释复合肥最高.不同施肥处理对土壤微生物群落结构的影响以缓释复合肥减量10%处理(SRF1)施用效果最好,可实现缓释复合肥在叶类蔬菜栽培中的减钾施用方式.

China is dependent on imported potash fertilizer in her agricultural production,andpotash reductions with slow/controlled release fertilizers are,therefore,important for the sustainabledevelopment of China'sagriculture.In an experiment conducted in Tongliang(purple soil with high contents of N and K)and Beibei(purple soil with low contents of N and K),the effects of slow-release compound fertilizers with 10%and 30%reductions in K(SRF1 and SRF2),respectively,on the rhizosphere soil microbes of three leafy vegetables,cabbage(Brassica chinensis),B.narinosa and lettuce(Lectuca sativa var.logifolia),were studied.The results showed that soil microbial content was markedly higher in Beibei than in Tongliang,and in the Tongliang experimental field,the bacterial,actinomycetes and fungal contents were significantly higher in the rhizosphere soil of B.narinosa thanthat of cabbage and lettuce.Compared with compound fertilizer(CF),SRF1 significantly increased the rhizosphere soil microbial content of cabbage,B.narinosa and lettuce in the Tongliang experimental field by 11.5%,27.7%and 22.2%,respectively.The rhizosphere soil actinomycetes content of lettuce in the Beibei experimental field increased significantly by 18.0%compared with CF andby16.4%compared with common compound fertilizer(CCF).Compared with CF,SRF1 and SRF2 significantly increased the rhizosphere soil fungal content of cabbage by 13.4%and 12.9%,respectively,in the Tongliang experimental field.In this field,the gram-positive and gram-negative bacterial content of the rhizosphere soils of cabbage,B.narinosa and lettuce treated with slow-release compound fertilizer were significantly higher than in those treated with CF and CCF.Therefore,among the different fertilizer treatments,the application of slow-release compound fertilizer with a 10%reduction in potassium(SRF1)produced the best effects on rhizosphere soil microbes.