Linda Benedict, Bush, Edward W., Owings, Allen D. | 8/4/2009 9:00:01 PM
Edward Bush, Allen Owings and Ann Gray
Nursery crop production in Louisiana and across the southeastern United States has experienced unprecedented growth in the past decade. In 1998, Louisiana ranked 17th nationwide in wholesale sales of nursery crops with more than $107 million and 20th nationwide in retail sales of lawn and garden products with $1.4 billion.
The most important consideration in commercial nursery production is availability of large quantities of high quality water for irrigation. A typical container nursery operation using an overhead sprinkler irrigation system requires 0.5 to 2.0 inches of water per acre per day. This is equivalent to between 12,500 and 50,000 gallons of water per acre per day or 5 to 10 acre-feet of water per production season. These amounts vary from one nursery to another. The upper end of this range is typically considered excessive, while the lower end can produce desirable quality plants only under a properly designed irrigation system maintained under ideal environmental conditions.
Nursery managers are exploring how to reduce water requirements by converting to alternative irrigation methods. This has included installation of drip irrigation systems, especially for larger containers, and use of a cyclic irrigation schedule. Cyclic irrigation dispenses the daily water allotment in more than one application with timed intervals between each one. Most nurseries previously irrigated on a daily basis, applying the daily water allotment in a single application, which is called continuous irrigation. The use of a cyclic irrigation system significantly decreases the amount of irrigation water applied and reduces the amount of nutrients leached from the container medium, thus increasing fertilizer efficiency. Compared to continuous irrigation, cyclic irrigation has been shown to reduce the volume of water runoff by as much as 30 percent and the amount of nitrate leached from the containers by more than 40 percent. Cyclic irrigation can be used with overhead and drip (micro-irrigation) systems.
One objective of LSU Agricultural Center studies has been to determine the efficiency of cyclic irrigation by measuring container leachate volume or effluent (excess water). Results indicate that cyclic irrigation reduces effluent, while improving water and fertilizer efficiency.
Edward Bush, Assistant Professor, Department of Horticulture; Allen Owings, Associate Specialist, and Ann Gray, Research Associate, Department of Horticulture, LSU Agricultural Center, Baton Rouge, La.
(This article was published in the summer 1999 issue of Louisiana Agriculture.)