Review on Potential of Liming for Sustainable Management Some Selected Soil Chemical Properties and Crop Yield Improved in Tropical Soil

Abstract

Acid soils of the tropical soil were greatly responsive to applications of lime fertilizer. Successive applications of lime drastically decreased exchangeable aluminum to the minimum level, and raised soil pH close to the optimum pH requirement of many cereals.  Other alternative materials include silicates of calcium or calcium and magnesium, wood ash and several industrial by-products such as slag that can produce modest amounts of other nutrients such as phosphorus and calcium. In order to produce a better crop yield on acid soils, farmers are recommended to apply alkaline materials such as lime (primarily calcium carbonate) to increase the soil pH and thus eliminate Al toxicity, and to apply P fertilizer to increase the bioavailable P in soil. The usual agricultural practice for most crops is to maintain a soil pH of 6.0-6.5 by the addition of lime, applied as calcium carbonate calcium hydroxide or calcium oxide. Traditionally, methods used to raise soil pH include; use of mulch from agro-forestry tree species, burning of sites to give ash and use of animal wastes although such materials are not available in the right amounts desired and in most cases, they are too bulky. However, in many developing countries, where semi subsistence agriculture prevails, the lack and/or high cost of lime prevent its use. Under such conditions, alternative means of managing soil acidity need to be developed. Research has shown that additions of green manures, FYM, and composts to acid soils can reduce Al toxicity and increase crop yields. So, government should either subsidize the lime or encourage more investors to produce lime in order to decrease the lime cost. The farmers’ practice like applying farmyard manure, compost and other organic wastes in backyard which can add organic matter to the soil should be appreciated and encouraged.