Variation among rice cultivars in DTPA-Fe content of rhizosphere soils and Fe uptake

摘要

A greenhouse experiment was conducted to study the dynamics of DTPA-Fe in the non-rhizosphere and rhizosphere soils under flooded conditions using different rice cultivars. The DTPA-Fe was higher throughout the study in the non-rhizosphere soils thanin the rhizosphere soils. However, the initially high DTPA-Fe decreased with time in the non-rhizosphere soil, which was possibly controlled by the equilibrium between pH and p Fe~(-2). In the rhizosphere soil also, the same trend and equilibrium existed, but the decrease was further influenced through the oxidation by rice roots. There was significant difference among varieties in influencing DTPA-Fe concentration of rhizosphere region. Variety IR 8 had the maximum DTPA-Fe in its rhizosphere and IR 22the minimum. Both varieties had significant difference in the Fe uptake. IR 8 had maximum uptake, followed by IR 20, pokkali, IR 42, IR 26 and IR 22.