Influence of Irrigation Water, Nitrogen and Phosphorus Nutrient Rates on Relative Weight Loss and Sprouting Characteristics of Seed Potato Tubers After Storage

Abstract

Potato has overtime generated special importance in most parts of Kenya and the world as a means of strengthening food security and increasing revenue for farmers. However, potato productivity and industry expansion have been constrained by the poor quality seed tubers being produced in the informal seed sector due to inadequate supply of initial planting materials, improper fertilizer management practices and irregular rainfall patterns. A study was done at the Horticultural Research and Teaching Farm of Egerton University to determine the effect of integration of irrigation water, nitrogen and phosphorus rates on seed tuber relative weight loss and sprouting characteristics after storage. The three factors were tested in a split-split plot design where irrigation water supply was assigned to main plots, N to subplots and P to sub-subplots. The treatments were replicated three times and the trial repeated once. The treatments consisted of three irrigation water rates (40%, 65% and 100% field capacity), applied throughout the potato growth period through drip tube lines. Nitrogen was supplied as urea (46% N) at four equivalent rates of 0, 75, 112.5 and 150 kg N/ha, while phosphorus was supplied at planting time as triple superphosphate (46% P2O5) at four rates of 0, 115, 172.5 and 230 kg/ha P2O5, which translated into 0, 50.6, 75.9, 101.2 kg P/ha. Data collected included relative percentage weight loss, number of sprouts and sprouting percentage. Data collected was subjected to analysis of variance and significantly different means separated using Tukey’s Studentized Range Test at p ≤ 0.05. The 100% compared to 65% and 40% irrigation water rates resulted in relatively high weight loss, sprout length and reduced the number of sprouts and sprouting percentage of seed tubers. N and P rates generally decreased the relative weight loss, improved the number of sprouts and sprouting percentage. It is recommended to apply low to intermediate irrigation water, intermediate to high N and P rates to reduce the percentage relative weight loss and sprouting characteristics.