Suitability of magnesite as a source of magnesium in acid rice soils of Kerala

Abstract

An incubation study and a potculture experiment were conducted to assess the suitability of magnesite in comparison with that of magnesium sulphate and dominate in karappadam (Moncompu, Alappuzha district) and laterite (Vellanikkara, Thrissur district) soils of Kerala. In the incubation study, these three Mg sources were added to the two soils at the rate of 25 and 50 kg MgO ha-1 and their transformations under submergence were studied for 180 days drawing samples at regular intervals of 15 days. The samples were analysed for Mg fractions, available Ca and K, pH and EC. In the potculture experiment using rice (Annapoorna) as the test crop, the direct and residual effectof magnesite, dolomite and magnesium sulphate were studied. The soils and levels of Mg application were the same as in the incubation study. Application of N, P and K was done uniformly in all the treatments . Soil and plant samples were taken at 15 days interval for the determination of uptake and avilability of nutrients , pH and EC. The residual effect of Mg fertilizers was assessed by continuing the experiment for the second season without the addition of Mg fertilizers.