土壤微生物对玉米秸秆还田的响应特征——亚热带石灰土与红壤的典型对比（英文）

Response characteristics of soil microbes on maize straw amendment——A typical comparison between subtropical limestone soil and red soil

【目的】探究亚热带岩溶区石灰土与非岩溶土红壤秸秆降解过程中微生物的响应特征,为更好地利用岩溶土地资源提供依据。【方法】选择广西桂林毛村岩溶地区石灰土和碎屑岩区红壤,进行为期160 d的室内玉米秸秆降解模拟试验,共设4个处理:石灰土加玉米秸秆(L+S)、红壤加玉米秸秆(R+S)、石灰土不加玉米秸秆(L)和红壤不加玉米秸秆(R),并在第0、3、7、14、21、28、42、56、84、98、133、147和160 d分别测定两种土壤中的玉米秸秆降解率、微生物数量、微生物量碳(MBC)和微生物氮(MBN)量。【结果】石灰土加玉米秸秆处理的秸秆降解率为77.00%,红壤加玉米秸秆处理的秸秆降解率为75.00%,相对于不加入秸秆的处理,其土壤微生物总量、细菌、真菌和放线菌数量及MBC与MBN含量均显著提高(P<0.05);石灰土中细菌、放线菌和真菌的数量比分别为48.67%、50.08%和1.08%,红壤中三者的数量比分别为61.79%、29.58%和8.62%。石灰土MBC和MBN分别比红壤高238.00%和165.00%。【结论】玉米秸秆还田能加速石灰土和红壤中微生物的生长和繁殖,且石灰土中的秸秆分解得更快更彻底,说明秸秆再利用在改善岩溶土壤肥力方面有巨大潜力。

【Objective】The response characteristics of microbes in the maize straw degradation process in limestone soil in subtropical karst and red soil in non-karst area were studied,which provided the basis for better utilization of karst land resources.【Method】For this,a 160 d laboratory simulation experiment on maize straw degradation was conducted using limestone soil in karst area and red soil in clastic area from Maocun,Guilin,Guangxi,China.Four treatments were investigated over a period of 160 days:limestone soil with maize straw(Lts),red soil with maize straw(Rts),limestone soil without maize straw(L),and red soil without maize straw(L).Maize straw decomposition rate,microbial quantity soil microbial biomass carbon(MBC)and microbial biomass nitrogen(MBN)in two soils were determined at 0,3,7,14,21,28,42,56,84,98,133,147 and 160 d.【Result】The cumulative maize straw decomposition rates in limestone soil with maize straw and red soil with maize straw were 77.00%and 75.00%respectively.Compared with the treatments without straw,addition of maize straw significantly increased total soil microbial quantity,bacteria,fungus,and actinomyces quantities,MBC,and MBN in both soils(P<0.05).In limestone soil,the quantity ratios of bacteria,fungus,and actinomyces were 48.67%,50.08%,and 1.08%respectively,whereas in red soil,these ratios were 61.79%,29.58%and 8.62%.MBC and MBN in limestone soil were 238.00%and 165.00%higher than those in red soil respectively.【Conclusion】Maize straw amendment accelerates microbial growth and reproduction in both limestone soil and red soil,but maize straw decomposes faster and more thoroughly in limestone soil than in red soil,which indicate the great potential of straw reutilization to improve karst soil fertility.