A study was conducted in a new field of northern highbush blueberry (Vaccinium corymbosum L. ‘Elliott’) to determine the effects of different irrigation methods on growth and water requirements of uncropped plants during the first 2 years after planting. The plants were grown on mulched, raised beds and irrigated by sprinklers, microsprays, or drip at a rate of 50%, 100%, and 150% of the estimated crop evapotranspiration (ETc) requirement. After 2 years, drip irrigation at 100% ETc produced the most growth among the irrigation methods with at least 42% less water than needed for maximum growth with microsprays and 56% less water than needed with sprinklers. Drip irrigation also maintained higher soil water content in the vicinity of the roots than the other methods but reduced growth when plants were over-irrigated at 150% ETc. Only 570 mm of irrigation water, or the equivalent of 1320 L per plant, was required over two seasons to reach maximum total plant dry weight with drip, whereas 980 mm or more water was needed with sprinklers and microsprays. Consequently, irrigation water use efficiency (defined as the difference in plant biomass produced under irrigated and rain-fed conditions divided by the total amount of irrigation water applied) was significantly higher with drip than with the other irrigation methods, averaging 0.41 g of total dry weight per liter of drip irrigation. In terms of both growth and water use, drip irrigation was the best and most efficient method to establish the plants.
WATER REQUIREMENTS FOR SOME WHEAT CULTIVARS IN NORTH NILE DELTA
