Improving Nutrient Availability and Rice Yield in Coastal Sandy Soils through Non-Conventional Soil Ameliorants

Abstract

Soil acidity is a major constraint limiting nutrient availability and rice productivity in the coastal sandy soils of Kerala. A field experiment was conducted during the first crop season of 2023 at Thaikadappuram, Kasaragod, Kerala, to evaluate the effectiveness of different soil ameliorants in improving soil properties, nutrient availability, plant nutrient uptake, and rice productivity. The experiment was laid out in a randomized block design with nine treatments and three replications using rice variety Athira. Treatments included lime, dolomite, gypsum, and calcium silicate applied at 100% and 125% calcium equivalent levels along with a control. The results revealed that application of soil ameliorants significantly improved soil pH, electrical conductivity, availability of major nutrients (N, P, and K), plant nutrient concentration, and yield attributes compared to the control. Among the treatments, dolomite applied at 125% calcium equivalent (T₇) proved to be the most effective. This treatment recorded the highest soil pH and nutrient availability throughout crop growth stages, along with superior plant nutrient content. Maximum grain yield (8800 kg ha⁻¹), straw yield (18463.09 kg ha⁻¹), and productive tillers were also observed under T₇. The improvement in crop performance was attributed to enhanced soil acidity amelioration, reduced nutrient fixation and toxicity, and increased availability of calcium and magnesium. The study demonstrates that dolomite can serve as an effective and sustainable soil amendment for enhancing soil fertility and rice productivity in acidic coastal sandy soils.