Response of β-glucosidase enzyme activity of soil to biochar applications in a crop rotation at Blacksea agroecosystem

Abstract

The use of biochar has emerged a potentially effective approach to improve soil function and promote crop performance. However, the specific impact of biochar on β-glucosidase enzyme activity (BGA) within crop rotation systems in the Black Sea agroecosystem requires further investigation. This study was conducted to determine the effects of rice husk biochar (RHB) and poultry manure biochar (PMB) on BGA in soils. Six biochar doses (0-control, 10, 20, 30, 40 and 50 t ha-1) were applied at the beginning of two wheat-cabbage red pepper rotation periods. The mean BGA at second rotation (73.71 µg pNP g-1) was significantly lower compared to the BGA of the first period (93.39 µg pNP g-1). The BGA value in control (94.51 µg pNP g-1) decreased with increasing biochar application doses (76.05 µg pNP g-1, 50 t ha-1) treatment. The mean BGA value in PMB treatment was slightly higher than that of RHB, but it was not statistically different between two biochar types. However, the decrease in BGA value (25.0%) in the highest RHB dose compared to control was more than two-fold compared to the decrease in PMB application (12.1%). The difference in carbon/nitrogen ratio between RHB and PMB can be attributed to the variation in BGA values observed at the application of same biochar doses. The decrease in BGA over the course of the two rotation cycles implies that biochar may have a long-term influence on soil carbon cycling.