Mineral fertilizer alters cellulolytic community structure and suppresses soil cellobiohydrolase activity in a long-term fertilization experiment

Nutrient inputs to soil can alter mineralization of organic matter and subsequently affect soil carbon levels. To understand how elemental interactions affect the biogeochemistry and storage of soil C, we examined soils receiving long-term applications of mineral fertilizer and manure-containing fertilizers. As cellulose is the dominant form of carbon entering arable soils, cellulolytic communities were monitored through enzymatic analysis, and characterization of the abundance (real-time PCR) and diversity (terminal restriction fragment length polymorphism, T-RFLP) of fungal cellobiohydrolases (cbhI) genes. The data showed that long-term mineral fertilization increased soil organic C and crop productivity, and reduced soil heterotrophic respiration and cellobiohydrolases (CBH) activity. Correspondingly, the diversity and community structure of cellulolytic fungi were substantially altered. The variation in cellulolytic fungi is mainly attributable to shifts in the proportion of Eurotiomycetes. In addition, CBH activity was significantly correlated with the diversity and community structure of cellulolytic fungi. These results suggest that enhanced C storage by mineral fertilizer addition occurs not only from extra organic carbon input, but may also be affected through the cellulose decomposing community in arable soil.