3879:
Irrigation Timing and Emitter Selection Affects Irrigation Efficiency and Plant Growth

Wednesday, August 4, 2010
Springs F & G
Donna C. Fare , USDA ARS, McMinnville, TN
Container nursery production requires large inputs of water and nutrients but often irrigation inputs exceed plant demand and lack application precision.  As a result of excess irrigation, excessive leaching of nutrients, such as nitrogen and phosphorus from container growing systems, occurs.  During a 3 year test, plant response and irrigation efficiency with micro-spray stakes combined with time of day of cyclic irrigation for production of container grown trees were evaluated. Irrigation efficiency was improved by 35% if applications were made in mid day or late afternoon with micro-spray stakes.  Container leachate volume was greater with early morning and evening irrigation than mid day or afternoon irrigation.  Nitrate-N and ortho-phosphate effluent was 67and 64% less, respectively, in container leachate from mid day and late afternoon irrigation compared to early morning irrigation. Micro spray-stake design affected irrigation efficiency.  Double sided stakes or rings had less overspray in #15 nursery containers than traditional fan style stakes. Height growth of Acer rubrum ‘Sun Valley’ maples was similar when trees were irrigated in early morning, in late afternoon or a combination of both. Trunk diameter growth was 10% larger with plants irrigated in mid day or late afternoon compared to plants that received only early morning irrigation.