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

ObjectiveThe response characteristics of microbes in the maize straw degradation process in lime-stone soil in subtropical karst and red soil in non-karst area were studied,which provided the basis for better utilization of karst land resources.MethodFor 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 de-termined at 0,3,7,14,21,28,42,56,84,98,133,147 and 160 d.ResultThe cumulative maize straw decom-position 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 quanti-ty,bacteria,fungus,and actinomyces quantities,MBC,and MBN in both soils(P<0.05).In limestone soil,the quan-tity 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.ConclusionMaize 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.