Response of potato to full and deficit irrigation under semiarid climate: Agronomic and economic implications

摘要

Yield, cost, and revenue functions of potato (cv. Agria) were developed from field experiments in 2007-2008, which were designed to determine the response of tuber yield to no irrigation for two weeks at tuber bulking (TB) and tuber ripening (TR). Deficit-irrigated treatments were compared to a well-irrigated control (C) throughout the growing season. The yield-profit maximization methodology of English (1990) was reviewed and a new procedure based on optimization software was proposed. Treatment with deficit irrigation at TB achieved marketable yield 12% lower than that obtained in the well-irrigated control (60.5 Mg ha(-1)), whereas deficit irrigation at TR reduced tuber yield by 42%, compared to the control. However, yield reduction was compensated by an increase in tuber dry matter in the deficit-irrigated treatments. The results of the newly proposed yield-profit maximization procedure show that when land is limiting, the level of water applied at which net income per unit of land is maximized (W-l) fits the yield maximizing (W-m) strategy, while when water is limiting, the level of water applied at which net income per unit of water is maximized (W-w) would result in as much water saving as 10-15% of total applied water. The results also suggest that the target yield that was obtained in the treatment with deficit irrigation at tuber bulking (53.6 t ha(-1)) was in the range of 500-560 mm of water application. We concluded that deficit irrigation at tuber bulking for two weeks is a suitable scenario for potato farming, with potential benefits resulting from reduced irrigation costs