Abstract
We investigated the changes in microbial biomass C and N, available soil N and neutral sugar composition induced by wheat straw and manure application in four types of central Hokkaido soils. 1) Microbial biomass C and N increased by organic material applications. Microbial biomass N / total N in wheat straw application soils showed a remarkable increase compared with the other two treatment soils. 2) There were significant positive linear correlations among available soil N, microbial biomass N and hot-water extractable C. Available soil N can be estimated by the value of hot-water extractable C. 3) Neutral sugar C increased by organic material applications, and especially, xylose C increased remarkedly by wheat straw application. Neutral sugar compositions were different among three treatments and four soil types. 4) There were significant positive linear correlations between available soil N, microbial biomass N and neutral sugar C. Moreover, microbial biomass N / total N showed a significant positive correlation with xylose C / mannose C. These results explain that the ratio of microbial biomass N in total N is affected by the neutral sugar composition in soil.
