Effect of tillage and residue management on enzyme activities in soils

Abstract

In this study we investigated the effect of tillage and residue management on activities of glycosidases, including cellulase, α-and β-glucosidases, and α-and β-galactosidases. The land treatments included three tillage systems (no-till, chisel plow, and moldboard plow) in combination with corn-residue placements in four replicated field plots. Results showed that activities of these enzymes were significantly greater in no-till/double mulch than in most of the other tillage and residue-management practices investigated. With the exception of glucosidases, mulching resulted in greater activities of cellulase α-and β-galactosidases. Compared with soils under bare or normal treatment in the no-till system, double mulch significantly increased the activities of the glucosidases. Relative to bare and normal treatments of no-till systems, the use of chisel plow did not significantly affect β-glucosidase activity, but significantly increased α-glucosidase activity. Mulching, generally, increased enzyme activities in soils. Linear regression analyses indicated that activities of the glycosidases were significantly (P<0.001) correlated with soil organic C, with correlation coefficients (r) ranging from 0.78^*** to 0.92^***. The activities of these enzymes decreased significantly with increasing depth of the plow layer. With the exception of cellulase activity (r=0.27), linear regression analyses showed that the activities of the other four glycosidases were significantly correlated with soil pH, with r values ranging from 0.40^* to 0.64^***. The activities of glycosidases were significantly intercorrelated, with r values ranging from 0.38^* to 0.89^***, suggesting that tillage and residue-management practices have similar effects on the activities of the enzymes involved in C cycling in soils.