Nitrogen, phosphorus and potassium requirements of kinnow in low-fertility soils of Punjab

摘要

The cultivation of kinnow mandarin (Citrus noblis X C. delicosa) has assumed a considerable significance recently in north India. Now, it has occupied the first position amongst all the fruits grown in Punjab (Chohan et al., 1). However, there is a declining trend in its plantation after a few years of satisfactory performance. The affected trees do not usually die but remain unproductive. Decline in kinnow has been attributed to cultural abuses, insect-pest attack, poor nutrition, poor soil air-water relations (Sharma and Mahajan, 5). Information on fertilizer requirement in kinnow is very meagre. Recommendations about its fertilizer requirement in Punjab are based only on preliminary observations (Jawanda, 2; Jawanda et al., 3 and Jawanda and Singh, 4). At present kinnow is being grown commercially in soils having low N and P and medium in K contents. There is no recommendation for application of phosphatic or potassic fertilizers for Punjab. Therefore, the experiment was conducted to find out the major nutrient requirement of kinnow in such soils.