Establishing optimal nutrient norms in leaf and soil for oil palm in India

Diagnosis and recommendation integrated system (DRIS)-based critical and optimum leaf nutrient standards for oil palm (OP) (Elaeis guineensis Jacq) have been estimated for some locations of India to find out the most critical nutrients. However, a well-established boundary line approach has not been evaluated for defining optimal ranges of leaf nutrients. Further, no defined standards are available for soil available nutrients in oil palm growing regions of India. Nutrient management in oil palm gains paramount importance due to its huge requirement as well as its spectacular influence on fresh fruit bunch (FFB) and oil yields. Therefore, apt norms need to be established for better productivity through precise nutrient management. With this objective, optimum concentrations for the most important leaf nutrients, their sufficiency ranges, nutrient ratios and their optimal ranges have been determined by employing boundary line approach and the results have been compared with that of DRIS approach based on average values of high yielding populations. Similarly, optimal soil available nutrient status in terms of optimal concentrations and their sufficiency ranges also have been standardized for oil palm and compared with DRIS method. For Krishna – Godavari basin area of Andhra Pradesh in India, the optimal concentrations of nutrients in oil palm leaves were established as 2.64, 0.16, 0.78, 1.3, 0.52, 0.16% for nitrogen (N), phosphorus (P), potassium (K), Calcium (Ca), Magnesium (Mg) and sulphur (S). For boron (B) the optimal concentration is 69.8 mg kg⁻¹ through BLA approach. For the same area, the optimal values of soil available nutrients were 452, 144, 388 kg of N, P₂O₅ and K₂O per ha, 1.96 and 1.7 meq 100 g⁻¹ of Ca and Mg respectively, and 68 mg kg⁻¹ for SO₄-S and 8.4 ppm for B. The optimal pH level was 6.6. A variation of up to 10% was recorded between DRIS and boundary line approach and for better management optimal nutrient standards need to be established for each agro-eco region.