Phytase activity in the rhizosphere of crops, trees and grasses under arid environment

Phytase activity in the rhizosphere of different crops, trees, and grasses were compared in an arid environment as affected by temperature and tillage. The rhizosphere activity was increased 37–103% compared to fallow soils (controls). Legumes contributed significantly more than pearl millet (Pennisetum americanum). Neem, Azadirachta indica, had highest phytase activity among the trees, and sewan grass, Lasiurus sindicus, resulted in more activity among grasses. A strong linear regression (r2=0.896; p<0.001) between the phytase activity and depletion of phytin P in the rhizosphere was observed. The activity was more under no-tillage than tillage conditions in annual crops and maximum at 35°C. Some phytase fraction probably was resistant to temperature treatments. This study indicates that phytase released in different plant rhizospheres had different temperature optima.