Co-Authors:
Shimshi, D., Dept. of Environmental Physiology and Irrigation, Agricultural Research Organization, Gilat Experiment Station, Negev, 85-280, Israel
Susnoschi, M., Dept. of Vegetable Crops, Agricultural Research Organization, Gilat Experiment Station, Negev, 85-280, Israel
Abstract:
The response of five potato cultivars (Alpha, Cardinal, Désirée, Spunta and Up-to-Date) to a range of amounts of irrigation nitrogen top dressing (N.t.) in a rainless region was studied by means of the line-source sprinkler method. The irrigation-to-evaporation ratio, Kp, ranged from 0.14 to 1.27 and N.t. from 12 kg/ha to 201 kg/ha, respectively. In all cultivars, the yield increased linearly up to Kp=1.0; at higher ratios there was a yield decline in all cultivars except for Cardinal, in which the yield function flattened off. Spunta was the highest yielding cultivar (16t/ha) in the dry range (Kp=0.14; N.t.=12 kg/ha). Désirée was the highest yielding cultivar (64 t/ha) in the wet range (Kp=1.0; N.t.=201 kg/ha), and Alpha was the lowest yielding cultivar in both the dry and wet range (9 and 46 t/ha, respectively). Leaf permeability, leaf water potential and photosynthesis rate decreased, and tuber dry matter percentage increased with decreasing Kp: these indices also varied with plant age, and among cultivars. Yields were adversely affected when soil water potential at the 30-cm depth dropped below -0.4 bar. © 1985 Kluwer Academic Publishers.