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Abstract
The United States is the leading producer of pecans worldwide, and Georgia is the leading production state within the United States. Over the years, pecan (Carya illinoinensis) trees have experienced higher density plantings which enhances the need for better water use efficiency to increase the sustainability of the orchard. As tree nut crops, such as pecans, face challenges related to water use efficiency and environmental sustainability, it is essential to develop practices that optimize resource use while maintaining high-quality yields. Hedge pruning, a technique that reduces tree canopy size, is increasingly adopted in pecan orchards to improve water efficiency, enhance light penetration, and manage tree growth. Additionally, hedge pruning enables more efficient water use in the humid climate of the southeastern United States. The objectives of this study were to determine if irrigation rates can be reduced on hedge-pruned pecan trees with no loss in pecan yield or nut quality. The study is a split-plot design with pruning serving as the main plot effect and irrigation serving as the split plot effect. On hedge-pruned trees, all growth beyond 8’ from the trunk on the East side of the tree was pruned in year 1 and on the West side of the tree in year 2. Trees were topped on each side in their respective years at an angle with a peak at 40’. No pruning will be done in year 3. Hedging treatments are arranged in three tree blocks with each irrigation treatment occurring once per block as follows: 1) Full irrigation; 2) Reduced irrigation; 3) Non-irrigated control. Hedged blocks were replicated four times, and the non-hedged blocks were replicated three times. Hedge pruning did not significantly affect water stress in the current study, although it did reduce yield in the initial years due to the removal of fruiting wood. However, by the third year, yield differences between hedged and non-hedged trees were minimal. Additionally, hedge pruning increased percent kernel and leaf area in pruned trees, highlighting its potential for improving nut quality. Furthermore, the reduced irrigation rate did not negatively affect yield or nut quality on hedged nor on non-hedged trees, suggesting that irrigation rates could be safely reduced by 34% from April-July, offering a sustainable approach to water conservation without compromising production. These findings underscore the potential for hedge pruning and irrigation adjustments to enhance pecan orchard management and sustainability in the southeastern U.S.