PARTIAL ROOTZONE DRYING TO SAVE WATER WHILE GROWING APPLES IN A SEMI-ARID REGION

Water availability represents the main environmental limitation in arid and semi-arid agro-ecosystems. In these regions, irrigation water is a scarce and expensive resource for apple and other horticultural production systems. The north-central part of Mexico, where 70% (similar to 44 thousand hectares) of apples are grown, is such a semi-arid system. The objective of this research was to determine the impact of partial rootzone drying (PRD) on tree physiology, yield, water use efficiency (WUE), and irrigation water use efficiency of Golden Delicious apple trees growing in a semi-arid region. Treatments were commercial irrigation (CI, as control) and PRD (50% of the irrigation water supplied to CI). The PRD trees had slightly reduced leaf xylem water potential, stomatal conductance, and transpiration rate. Yield, fruit size and quality, vegetative growth, and pruning weight were not modified by the irrigation treatments. Over three years, average WUE increased by 51% under PRD irrigation and water savings were similar to 3, 240 m3 water per hectare. Therefore, PRD is a potential irrigation technique to make apple production sustainable not only in the semi-arid regions of Mexico, but also in other regions where water resources are becoming insufficient. Copyright (C) 2011 John Wiley & Sons, Ltd.