Responses Of Soil Ecological Stoichiometry To 5 Kinds Of Organic Matters Added In Pinus Tabuleaformis Forests

Ecological stoichiometry is the main indicator that reflects the cycle of carbon(C),nitrogen(N),and phosphorus(P)in the soil,and it integrates the variability of the soil ecosystem.External nutrient input changes the distribution pattern of the elemental state by causing changes in the composition of soil and microbial biomass.With the pinus tabuleaformis forests as the research object in Taiyue Mountain of Shanxi Province,we added pinus tabuleaformis leaf(P),Quercus liaotungensis leaf(Q),sawdust(S),corn straw(C),and biochar(B)to the soil,separately.We analyzed the soil in May and August 2017,and investigated the effects of different organic matters on SOC,TN,TP,MBC,MBN,and MBP.We revealed the relationship between soil nutrients,microbial biomass,and stoichiometric ratios.The conclusions are as follows:(1)The differences in SOC,TN,and TP of the soil under different treatments did not reach significant levels,and there was no significant difference between the two months.The differences in soil C/N,C/P,and N/P were not significant or small,and the differences between the two months were not significant.It shows that the addition of organic matters could not affect the balance of total soil nutrients.(2)MBC,MBN,and MBP had different trends in the comparison between the two months:MBC had a trend of more than August in May,MBN had no difference in two months,and MBP had a trend of more than May in August.For microbial biomass stoichiometric ratios:MBC/MBN,MBN/MBP trended to be greater than August in May,and MBC/MBP did not differ significantly between the two months.The microbial community composition differed greatly between the two months.(3)The molar ratio of soil C:N:P and microbial biomass C:N:P in Pinus tabulaeformis forests was 267:17:1 and 16:3:1,respectively.C and N are higher than the global average in the proportion of total soil nutrients,and below the global average in microorganisms.Phosphorus(P)may be a limiting factor for the growth of microorganisms in the soil of Pinus tabulaeformis forests.Insufficient P limits microbial use of more C and N.(4)The addition of organic matters could not improve soil physical and chemical properties of Pinus tabulaeformis forests in a short period of time,and there was little or no difference in the soil after the addition of different organic matters.