3.6. Enzyme activities in rhizosphere
In the rhizosphere of maize, the activities of urease and phosphatase were 21% and 57% higher under 20 cm than 30 cm of topsoil depth. In addition, decreasing the topsoil depth to 10 cm further increased the activities of urease, phosphatase and invertase which were 22%, 162% and 14% higher compared to 30 cm of topsoil depths.
In soybean rhizosphere, urease activity was by 22% higher, but phosphatase activity 58% lower under the 10-cm than the 30-cm topsoil depth. The activities of phosphatases and invertase were 49% and 19% lower under 20 cm than 30 cm of topsoil depth, respectively (P< 0.05, Fig. 6c).