Influence of drying and reflooding on phosphorus and iron dynamics affecting rice growth

摘要

Dynamics of P and Fe in 2 each of Alfisols and Ultisols, under intermittently dried and reflooded conditions and their effects on rice growth and yield were studied in green house. Six different soil drying and reflooding cycles were imposed to measure their influence on pH, Eh, P and Fe~(+2) of soil solution. On drying, soil solution pH decreased, Eh increased and concentrations of P and Fe~(+2) decreased. Reflooding raised pH, decreased Eh and increased concentrations of P and Fe~(+2) at a lower rate. Soil drying and reflooding reduced uptake of P and Fe~(+2) by rice plant. Soil drying at any stage, decreased rice yield, except in Tropudult, where the reverse happened.