Interaction of Peach Seedlings to NO3:NH4 Ratios in Nutrient Solutions1

Abstract

Abstract Peach [ Prunus persica (L.) Batsch] seedlings of ‘Siberian C’, ‘Tzim Pee Tao’, NA 8, and 152A1–2 were grown for 64 days in nutrient solutions with constant N concentration, but the ratio of NO 3 to NH 4 in the nutrient solution varied from 100:0 to 0:100. The greatest growth occurred when the NO 3 :NH 4 treatment was 50:50 or 25:75. The poorest growth occurred when NO 3 was the sole N source in the nutrient solution. Significant interaction of nutrient concentrations occurred with the different rootstock and N ratios in all tissues studied. The N concentration in leaves and roots was highest in seedlings grown in N treatments of 100:0 or 75:25. The concentrations of P, Ca, and Mg in the leaves, stems, and roots of all cultivars decreased with each increment increase in the NH 4 concentration in the nutrient solution. The relative growth rate and N uptake rate of all seedlings increased with high NH 4 concentrations. The uptake rates of P, K, Ca, and Mg were highest for NO 3 :NH 4 treatments of 50:50 or 25:75. Chlorosis developed on margins of leaves mid-way on the main stem on all seedlings with NO 3 :NH 4 treatments 50:50, 25:75 and 0:100. The disorder occurred in the mature leaves of all cultivars but did not affect expanding leaves.