Irrigation Management of Young Pecan Trees

A recent survey documents the planting of over 15,000 acres of new pecan [Carya illinoinensis (Wangenh.) K.Koch)] orchards in Georgia from 2010-2014.  Water is key to the growth of young pecan transplants; however, there are no research-based recommendations for irrigation rates on young non-bearing pecan trees. There are also many questions regarding the most efficient method of irrigating young pecan trees to get them into production quickly. The objectives of this study where to determine appropriate irrigation rates for young pecan trees and to compare growth of young pecan trees with drip and microsprinkler irrigation. Two experiments were conducted at the UGA Ponder Research Farm near Tifton, GA. beginning in 2014. The following treatments were evaluated to determine irrigation rate requirements for newly transplanted pecan trees; 1) 302 L per week; 2) 651 L per week; 3) Non-Irrigated.  A separate experiment compared growth of newly transplanted trees with drip and microsprinkler irrigation using the following treatments; 1) microsprinkler at 651 L per week; 2) drip irrigation at 182 L per week; 3) drip irrigation at 651 L per week; and 4) non-irrigated.   Single tree plots were arranged in a randomized complete block design with 5 replications in both experiments. Parameters evaluated for both experiments include tree caliper, shoot growth, stem water potential (water stress), and soil moisture. Pecan tree trunk diameter increased with increasing water application rate. Pecan tree trunk diameter growth was greatest at the irrigation water application rate of 651 L per week. Both irrigation rates resulted in a greater trunk diameter increase than that of non-irrigated trees. Drip irrigation at 182 L per week resulted in similar growth as that observed for trees receiving 651 L per week using drip or microspinklers. Each irrigation method resulted in increased trunk diameter compared to non-irrigated trees.