Soil Nutrient Status and Leaf Nutrient Norms in Oil Palm (Elaeis Guineensis Jacq.) Plantations Grown in theWest Coastal Area of India

Oil palm (Elaeis guineensis Jacq.) 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 64 oil palm plantations in the state of Goa lying in the west coastal region of India. Soil pH, electrical conductivity (EC), organic carbon (OC), available potassium (K) (ammonium acetate-extractable K) (NH4OAc-K), available phosphorus (P) (Bray's-P), exchangeable calcium (Ca) (Exch. Ca) and magnesium (Mg) (Exch. Mg), available sulphur (S) (calcium chloride-extractable S) (CaCl2-S), and hot water soluble boron (B) (HWB) in surface (0-20 cm depth) soil layers ranged from 4.25 to 6.77, 0.05 to 1.06 dS m(-1), 5.07 to 48.4 g kg(-1), 58.1 to 1167 mg kg(-1), 1.80 to 415 mg kg(-1), 200 to 2997 mg kg(-1), 36.0 to 744 mg kg(-1), 3.00 to 87.7 mg kg(-1) and 0.09 to 2.10 mg kg(-1), respectively. Diagnosis and Recommendation Integrated System (DRIS) norms were established for different nutrient expressions and were used to compute DRIS indices. As per DRIS indices, the order of requirement of nutrients in the region was found to be P > Mg > K > nitrogen (N) > B. Optimum leaf nutrient ranges as per DRIS norms varied from 1.64 to 2.79%, 0.36 to 0.52%, 0.37 to 0.75%, 0.89 to 1.97%, 0.35 to 0.63%, 0.89 to 1.50%, 3.10 to 13.9mgkg(-1), 7.50 to 32.2mgkg(-1), 35.0 to 91.1mgkg(-1), 206 to 948mgkg(-1), and 895 to 2075mgkg(-1) for N, P, K, Ca, Mg, S, B, copper (Cu), zinc (Zn), manganese (Mn), and iron (Fe) respectively. On the basis of DRIS-derived sufficiency ranges, 14, 5, 11, 6, 6, 6, 8, 2, 3, 6, and 16% of leaf samples had less than optimum concentrations of N, P, K, Ca, Mg, S, B, Cu, Zn, Mn, and Fe respectively. The optimum ranges developed can be used as a guide for routine diagnostic and advisory purpose for balanced utilization of fertilizers.