Potential of partial rootzone drying as an alternative irrigation technique for potatoes (Solanum tuberosum)

The increasing demands on limited water supplies worldwide require the adoption of more efficient irrigation techniques for sustainable production in agriculture. Partial rootzone drying (PRD) is one of the techniques that offer potential saving of irrigation water. This technique involves alternate irrigation to two sides of a plant root system. The studies reported here investigated PRD irrigation regimes and the optimum time of starting PRD in potatoes grown in a protected environment. In the first experiment, plants of the potato cv. Estima were exposed to five different irrigation treatments and a fully watered control at tuber initiation. The treatment that performed most similar to the control was alternate PRD to field capacity (APRD₁₀₀). This treatment produced similar total leaf area, haulm fresh and dry weights, plant water status and no significant yield reduction compared with the control plants. The APRD₁₀₀ treatment utilised 29% less water and increased water use efficiency (WUE) by 19%. In the second experiment, the APRD₁₀₀ irrigation was started at 2, 4, 6, 8 and 10 weeks after plant emergence. Vegetative growth and yield increased with the delay of the APRD₁₀₀. APRD₁₀₀ started at 6 weeks after emergence did not significantly reduce fresh tuber yield but received 21% less total water with a 19% increase in WUE. The results indicate that PRD may have potential use in the potato crop for conserving irrigation water with minimal loss of yield.