Critical nutrient ranges for potassium in potato leaves and petioles

Abstract

SummaryTwo field experiments were conducted in 1982–83 and 1983–84 for establishing critical nutrient ranges (CNR) for potassium in leaves and petioles of potato (Solanum tuberosum, L.) to be used as standards for assessing plant nutrient status at different periods of plant growth. Potassium was applied at 0, 42, 84, 126 and 168 kg K ha−1 alone and in combination with 30 t ha−1 farmyard manure. The K concentration in leaves and petioles increased with increase in applied K and decreased with maturity. Relative yields at 95 and 100% of the maximum were obtained with 85 and 106 kg K ha−1. The CNR at 95 and 100% of the maximum yield were 5.04 to 5.15%, 4.17 to 4.55% and 3.68 to 3.89% for fourth leaf and 8.15 to 8.49%, 7.70 to 8.47% and 7.12 to 7.60% for fourth petiole at 30 days after planting (tuber size up to 2 cm), at 45 days (2–5 cm tubers) and at 60 days (5–7 cm tubers). K concentration in petioles 30 days after planting gave the closest relationship (r = 0.95**) with tuber yield.