Soil Nutrient Status and Leaf Nutrient Norms in Oil Palm (Elaeis guineensis Jacq.) Plantations Grown on Southern Plateau of India

Abstract

Oil palm is a heavy feeder of nutrients and requires balanced and adequate supply of nutrients for optimum growth and yield. Information regarding soil nutrient status and leaf nutrient concentration is very much required for proper fertilizer application. Therefore, a survey was conducted for assessment of soil nutrient status and leaf nutrient concentration in 42 oil palm (Elaeis guineensis Jacq) plantations in the state of Karnataka, situated in southern plateau of India. In surface soil layers, soil acidity (pH), electrical conductivity (EC) and organic carbon (OC) content ranged from 4.91 to 8.74, 0.10 to 2.54 dS m−1 and 1.17 to 28.9 g kg−1 respectively. The values of available potassium (K) (NH4OAc–K), phosphorus (P) (Olsen-P) and exchangeable calcium (Ca) (Exch. Ca) varied from 31.2 to 386 mg kg−1, 7.69 to 242 mg kg−1 and 156 to 1273 mg kg−1 respectively. The concentration of exchangeable magnesium (Mg) (Exch. Mg), available sulphur (S) (CaCl2-S) and hot water soluble boron (B) (HWB) ranged from 52.8 to 307 mg kg−1, 2.25 to 73.5 mg kg−1 and 2.29 to 16.0 mg kg−1 respectively. Diagnosis and recommendation integrated system (DRIS) norms were established for different nutrient expressions and it was used to compute DRIS indices. As per DRIS indices, the order of requirement of nutrients in the region was found to be K > P > nitrogen (N) > B > Mg. Optimum leaf nutrient ranges varied from 2.24 to 2.97 %, 0.08 to 0.14 % and 0.78 to 0.91 % for N, P and K respectively, from 0.74 to 1.53 %, 0.25 to 0.98 % and 0.72 to 1.09 % for Ca, Mg and S respectively and from 5.71 to 31.0 mg kg−1, 7.42 to 12.9 mg kg−1, 33.6 to 58.6 mg kg−1, 82.5 to 681 mg kg−1 and 82.8 to 936 mg kg−1 for B, copper (Cu), zinc (Zn), manganese (Mn) and iron (Fe) respectively. On the basis of DRIS derived sufficiency ranges, 57, 24, 62, 3, 3, 9, 7, 5, and 26 % leaf samples were having less than optimum concentration of N, P, K. Ca, Mg, S, B, Cu and Mn respectively. The optimum ranges developed can be used as a guide for routine diagnostic and advisory purpose for balanced utilization of fertilizers.