Influence of flooding on electrochemical and chemical properties of West African soils

An understanding of the influence of flooding on electrochemical and chemic al properties of soils provides insight needed in their management for rice production in West Africa. With this objective, the influence of flooding on electrochemical and chemical properties of 15 lowland soils from five ri ce producing countries in West Africa was studied. The soils were held unde r flooded conditions in greenhouse pots for 15 weeks. Soil pH and redox pot ential (Eh), and anoxic soil solutions drawn weekly were monitored for the changes with respect to major and micronutrients. The electrochemical prope rties of the soils and their solutions with time tended to stabilize in a n arrow range. Soils widely differed in their capacities to release ammonium, P, K, Ca, Mg, Fe, Mn and Zn in soil solution and thus provided useful info rmation regarding the potential deficiencies of plant nutrients, and also, for the occurrence of Fe toxicity to lowland rice. Measurements made on the soil solution phase of the soils provided information for predicting the d ynamic relationships among Eh, pH and Fe(II). The soil solution EC was clos ely related to the solution concentrations of K, Ca and Mg. The soils diffe red in the pattern and in the amounts of Fe released in soil solution and t his information may be helpful in devising a strategy for the management of Fe toxicity to lowland rice. (C) 1999 Elsevier Science B.V. All rights res erved.