3.2. Root and shoot biomass
Root biomass of maize under the 10-cm topsoil was 35% and 10% lower at V7 and R3, respectively, compared to the 30-cm topsoil depth (P< 0.05, Fig. 2a). Similarly, shoot biomass also decreased with the decrease in topsoil depth except for 20-cm topsoil depth at R3 (P < 0.05).
In comparison, root biomass of soybean was significantly increased by 27% and 34% under the 20-cm topsoil depth at R1 and R6, respectively, than under the 30-cm topsoil depth. However, the 20-cm and 10-cm topsoil depths resulted in 27% and 36% of decrease in shoot biomass at R6, respectively, compared to 30 cm topsoil depth (P < 0.05, Fig. 2d).