Delineation of soil nutrient constraints of cashew orchards in India and management alternatives

Abstract

Cashew growing soils are generally deficient in plant nutrients mainly due to the landscape settings in which it is traditionally grown. The yield gap analysis revealed that the optimum production potential of cashew is yet to be tapped. Poor nutrition is likely to be one of the major factors contributing to low nut yield and quality. Optimization of cashew productivity and quality requires an understanding of the nutrient requirements of the tree, the factors that influence nutrient availability and the methods used to diagnose and correct deficiencies. For this detailed survey cashew growing areas is required. Timely management interventions are necessary to stop the depletion of soil nutrient reserves and to realize maximum yield from cashew. This study was undertaken to assess the soil nutrients limiting the productivity of cashew in India and to suggest management alternatives. Regional surveys were carried out in cashew plantations of Puttur, Vengurla, Bhubaneswar, Bapatla, Pilicode and Vridachalam. Soil and leaf samples were collected from 70 orchards in each location. Cashew orchards sampled were acidic and non saline. Organic carbon content of cashew growing areas was on the higher side except for Bhubaneswar, Bapatala and Vridachalam. These soils were deficient in available N, P and low to medium in K. Among the DTPA extractable micronutrients, soils were deficient in Zn and Cu. Soil fertility and nutrient supply is one of the important factor deciding yield and quality of the produce. At field and orchard level, the nutrition aspect is not properly taken care of, causing continuous nutrient mining and deterioration of soil health, apart from yield decline. Various soil fertility management options are discussed in the paper. Management options for soil acidity, major and micronutrients and nutrient management under organic farming systems are discussed.