Long-Term Fertilization Effects on β-Glucosaminidase Activity in a Chinese Mollisol

Abstract

Soil polysaccharide chitin is hydrolyzed by β-glucosaminidase (EC 3.2.1.30) and yields glucosamine, making β-glucosaminidase an important enzyme in C and N cycling in soils. This study was carried out to investigate the effects of long-term organic manure and chemical fertilizer on the activity of β-glucosaminidase in Chinese Mollisols. The activity values were significantly affected by long-term organic manure and chemical fertilizer. For the effects of organic manure, β-glucosaminidase activity was the greatest in M1(30t manure ha−1per year) and the least in M0(no manure) treatment, while β-glucosaminidase activity on M2treatment (60t manure ha−1per year) showed an inhibition effect compared with the M1treatment. For chemical fertilizer addition, the activity of β-glucosaminidase was the highest in N treatment, followed by NPK, NP, and no chemical fertilizer treatment (CK). These results indicated that β-glucosaminidase activity was sensitive to fertilization, especially the manure and N fertilizer. Correlation analysis showed that the activity of β-glucosaminidase was significantly correlated with organic C, total N, microbial biomass C, alkalified N, Olsen P, available K, and glucosamine, suggesting that β-glucosaminidase activity could be as an index to evaluate the fertility of soil and its significance for the study of soil biochemistry. Therefore, we assumed that the activity of β-glucosaminidase may provide reliable indicator for the long-term fertilization effect on N transformation in soil.