Journal of the Indian Society of Soil Science

A study was conducted on soil and plant nutritional status of sapota (Manilkara achras M. Fosberg) in order to identify the nutrients that are deficient/low and to formulate optimum nutrient range by surveying 106 sapota orchards, collection of leaf and soil samples in sapota growing districts of Raichur, Dharwad and Belgaum districts/northern Karnataka. The soil available N, P and K ranged from 70.7 to 154, 5.33 to 96.0 and 56 to 363 mg kg⁻¹, respectively. The available Ca, Mg and S content of soil ranged from 1366 to 2363, 287 to 573 and 19 to 45 mg kg⁻¹. Wide range was noticed for soil DTPA extractable Fe, Mn, Zn and Cu. However, hot water soluble B ranged from 0.312 to 0.538 mg kg⁻¹. The yield limiting nutrients differed from orchard to orchard though some of the nutrients were more prominent. The optimum leaf N ranged from 1.51 to 2.09%, P from 0.06 to 0.15% and K from 0.83 to 1.44%. The optimum concentration ranged from 1.36 to 2.34% for Ca, 0.54 to 0.68% for Mg and 0.48 to 0.80% for S. Among the micronutrients, optimum Fe, Mn, Zn, Cu and B concentrations ranged from 109 to 206, 49 to 99, 13.3 to 21.9, 3.76 to 9.10 and 34.8 to 66.8 mg kg⁻¹, respectively for sapota (cv. Kalipatti). The optimum ranges developed served as a guide for routine diagnostic and advisory purpose of nutrient status of the orchards of Northern Karnataka.