Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/22/2005
Publication Date: 9/1/2005
Citation: Vories, E.D., Teague, T.G., Espinoza, L., Ismanov, M. 2005. Judd hill drip irrigation and fertigation comparison. 11th Annual Judd Hill Cotton Technology Field Day Tour Book, Judd Hill, AR. Judd Hill Plantation. P. 4.
Technical Abstract: To assess the potential of drip irrigation in NE Arkansas, the Judd Hill Foundation funded installation of a Netafim (mention of trade names or commercial products is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture or University of Arkansas) subsurface drip irrigation system (SDI) on the Judd Hill Plantation in 2004. Drip lines were buried every other middle at 12 inches deep, with emitters placed every 24 inches. A fertilizer injector was installed to facilitate the application of fertilizer through the drip lines. Before any fertilizer could be injected, irrigation water had to be treated due to the high concentration of iron and associated iron-reducing bacteria in the area’s irrigation water. Water treatment was automated with a system provided by Flo-Tec Inc. (http://www.flo-tecinc.com/) that consisted of an injector and NIC® solution. The NIC solution was injected during every irrigation or fertigation event. This year’s objectives were a) to automate the water treatment component of the system, and b) to compare a conventional nitrogen fertility program to a nitrogen fertigation program (fertilization through the drip system). The test site consists of 12 acres, which were divided into 6 watering zones of 2 acres each. Zones 1, 3, and 5 were designated to receive fertilizer conventionally, while zones 2, 4, and 6 received fertilizer through the drip lines. The cotton cultivar Stoneville 5242 was planted on May 9. Phosphorus, potassium, sulfur, boron, and 30 lb N/A were applied preplant to all zones. The conventional fertility program received a total of 100 lb N/A, with the remaining 70 lb N/A (UAN 32%) applied at match head square. The fertigated zones received a total of 120 lb N/A. However, fertilizer was applied in weekly increments to total 70-80 lb N by first bloom, with the remaining applied soon after plants reached cutout. The nitrogen source was UAN 32%. At first bloom, a solution of potassium thiosulfate was injected at an equivalent rate of 10 lb K2O/A and 7.5 lb SO4-S/A. Irrigation amounts were calculated based on: a) the cotton crop coefficient at a particular growth stage, b) replacing 85% of ET (evapotranspiration), and c) a 100% irrigation efficiency.