Abstract: The present research investigated the status of Si, Fe, Mn and Al in rhizosphere of two red earths and two paddy soils after planting rice and its effect on rice growth and element absorption with the combination of rhizobox and pot cultivation experiment. The results show that active Fe and Al are accumulated in the rhizosphere of red earths after rice planting, active Mn is less in the rhizosphere, while active Si is not conspicuous deficient and accumulated on occasion. In paddy soils, after growing rice, active Fe and Al in the rhizosphere has a definite depletion, active Mn has a high depletion, while active Si is depleted very obviously. These differences result in the decrease of element absorption, such as Si, Pand Mn during the rice growing period in two red earths. At the same time, Fe and Al are accumulated in both roots and shoots, and the element absorption and rice growth are hindered. All these findings should help to understand material cycling in rhizosphere microecosystem.

Key words: Accumulation, Depletion, Rhizobox, Rhizosphere