Leaf and soil nutrient norms in mango (Mangifera indica L.) grown in tribal belt of southern Gujarat

Tribal area of southern Gujarat (taluk Vansda in Navsari district) was surveyed to assess the nutrient status of mango (cultivar Rajapuri) orchards in relation to their productivity. To achieve a yield of 2.0 to 7.5 t ha⁻¹, the optimum leaf N may range from 0.89 to 1.93 g per 100 g dry matter (dm), P from 60 to 110 mg per 100 g dm and K from 1.02 to 2.01 g per 100 g dm. Secondary nutrient namely S (107 to 169 mg per 100 g dm) and micronutrient namely Zn (11 to 16 μg g⁻¹) status were also worked out along with soil parameters for the targeted yield using Diagnosis and Recommendation Integrated System. Study indicated low N, Mg, Mn and Zn in large number of orchards. Although many orchards were low in nutrients, the status was expressed neither in leaf nutrient content nor in the form of deficiency symptoms due to “hidden hunger”. Continuous exhaustion may lead to decline in growth, productivity and quality of mango, unless integrated nutrient management is taken up and practised. In soils, 0.40 to 0.80% organic carbon, 42 to 180 μg g⁻¹ available N, 6 to 10 μg g⁻¹ available P, 100 to 730 μg g⁻¹ available K, 250 to 1600 μg g⁻¹ available Mg, 10 to 16 μg g⁻¹ available S and 1.0 to 2.0 μg g⁻¹ available Zn and 25 to 100 μg g⁻¹ available Mn would provide optimum yield of mango fruits under the situations of the project area. In the case study, taking large number of orchards under investigation, the nutrient norms developed were refined. Nutrient recommendations were made considering nutrient need, plant nutrient status as assured by leaf analysis and soil fertility evaluation. Study indicated that 53% orchards were giving very low to low yields and are not economically sustainable.