Response of Young Pecan Trees to Irrigation in a Humid Climate

The prolonged period from tree planting to first commercial harvest of pecan [Carya illinoinensis (Wangenh.) K. Koch] provides incentive for many growers to intensively manage young trees to induce commercial production as soon as possible. This management includes irrigation. However, there remain very few data regarding the irrigation requirements of young pecan trees grown under southeastern U.S. orchard conditions. The objectives of this study were to determine appropriate irrigation rates for young pecan trees and to compare growth of young pecan trees with drip and microsprinkler irrigation. Parameters evaluated for both experiments include trunk diameter growth, stem water potential (water stress), leaf area, leaf length, leaf width, and chlorophyll index. These results suggest that irrigation is beneficial to the growth, vigor, and alleviation of water stress on young pecan trees in the establishment phase grown in the temperate region of the southeastern United States. There was no difference in young pecan tree growth and vigor for microsprinkler irrigated trees at 304 L per week (lpw) compared with 650 lpw from the year of planting through the third leaf. Similarly, drip irrigation at 182 lpw appears to result in equal tree growth compared with both drip and microsprinkler irrigation at over 600 lpw.