**2.12 Effect of rice husk biochar on shoot, root, and total dry weight of maize under drought stress**

In drought stress shoot dry weight of maize reduced, but root dry weight increased, because under drought conditions for searching water, root growth increased, thereby increasing dry weight of root. Application of rice husk biochar reduced the effects of drought. The dry weight of root and shoot varied significantly with the application of biochar under drought conditions (**Table 8**).

Under control condition (80% of FC), 60% of field capacity, and 40% of field capacity, highest dry weights of shoot were 84.1, 83.1, and 75.9 g, respectively, when biochar was applied at 20 t/ha, and lowest dry weights of shoot were 75.4, 68.4, and 63.8 g, respectively, when no biochar was applied. Under control condition (80% of FC), 60% of field capacity, and 40% of field capacity, lowest dry weights of root were 12.4, 15.6, and 16.8 g, respectively, when biochar was applied at 20 t/ha, and highest dry weights of root were 17.5, 26.8, and 27.3 g, respectively, when no biochar was applied. Total dry weight of maize plant was reduced at drought stress conditions, but reduction was not significant. When biochar is applied at different doses under drought conditions, total dry weight increased (**Table 8**). Under control condition (80% of FC), 60% of field capacity, and 40% of field capacity, highest total dry weights were 98.8, 97.0, and 93.9 g, respectively, when biochar was applied at 20 t/ha, and lowest total dry weights were 93.1, 91.1, and 89.3 g, respectively, when no biochar was applied. [45] found that root dry weight increased, while shoot dry weight decreased under drought conditions. [46] marked shoot dry weight increased under drought conditions due to application of biochar.
