Pecan trees have high water requirements, using as much as 60 inches of total water (including rainfall) during the growing season. Georgia receives an average of 50 inches or more of rainfall annually. While the rainfall received certainly meets a portion of the water requirement for pecan trees, periods of moisture stress occur during the growing season, particularly during the months of August and September when pecans are in the kernel filling stage and water demand is at its peak. Thus, irrigation has been proven to markedly enhance pecan production in the region. With increasing agricultural water use, a growing population, and declining groundwater levels, irrigation efficiency in the region is necessary for sustainability. Drip and micro-irrigation system design capacity for a mature pecan orchard should be 3600-4000 gallons of water per acre per day. Because of evaporation losses, solid-set sprinkler irrigation can require as much as 3 times more supplemental water than drip or micro-irrigation. Solid set irrigation systems should have a design capacity of 1.5–2 inches per week. Water stress in pecan is correlated with soil moisture from budbreak through the end of nut sizing. Pecan trees bearing a moderate to heavy crop load may undergo water stress during the kernel filling stage regardless of soil moisture level. This suggests that crop load and nut development drive the tree's demand for water.
Status and Revision History
Published on Oct 25, 2016