WATER REQUIREMENTS OF YOUNG BLUEBERRY PLANTS IRRIGATED BY SPRINKLERS, MICROSPRAYS AND DRIP

Abstract

A study was done to determine the effects of irrigation method on water use by young northern highbush blueberry (Vaccinium corymbosum L. 'Elliott'). Plants were irrigated by overhead sprinkler, microspray, or drip at 50, 100, and 150% of the estimated crop evapotranspiration (ETc) requirement. Irrigation was applied twice a week by sprinklers and three times per week by microsprays and drip. During the first two years after planting, plants irrigated by drip required only half the water for maximum shoot production as those irrigated by sprinklers or microsprays, using 203 mm (Jul.-Sept.) the first year and 376 mm (Apr.-Sept.) the following year. Overall, shoot dry weight was highest when plants were irrigated at 100% ETc by drip or at 150% ETc by microsprays. The benefit of these two treatments was likely due to higher soil water content and/or higher irrigation frequency, which probably enhanced plant water status over the other treatments. Based on plant responses to water applications, additional water (>150% ET c) may further improve growth with microsprays but does not appear liable to improve it with sprinklers and drip. In fact, irrigation at 150% ETC saturated the soil and significantly reduced shoot dry weight with drip. Further study is underway to determine how these irrigation methods will affect production and water use in mature plants.