What is in this article?:
• Irrigation Water Management (IWM) programs available through the USDA's Natural Resources Conservation Service can help growers determine and control the volume, frequency, and application rate of irrigation water in a planned, efficient manner.
• This is top-of-field management that helps with control of inputs and limits tailwater losses.
IRRIGATION WATER MANAGEMENT programs available through the USDA’s Natural Resources Conservation Service can help producers achieve more efficient use of water resources.
As irrigation continues to expand and pumping costs increase, producers can utilize a number of tools and services through the USDA’s Natural Resources Conservation Service to help them more efficiently water their crops.
Some offer cost-share assistance, says Paul Rodrigue, supervisory engineer for USDA/NRCS Area 4 at Grenada, Miss.
“Our Irrigation Water Management (IWM) programs can help growers to determine and control the volume, frequency, and application rate of irrigation water in a planned, efficient manner,” he says.
“This is top-of-field management that helps with control of inputs and limits tailwater losses,” he says.
IWM can be used as part of a conservation management system to support one or more of the following:
• Manage soil moisture to promote desired crop response/yield quality;
• Optimize use of available water supplies/water conservation;
• Minimize irrigation-induced soil erosion;
• Decrease non-point source pollution of surface and groundwater resources, reducing/eliminating tailwater;
• Reduced energy consumption.
“This practice is applicable to all irrigated land,” Rodrigue says. “An irrigation system adapted for site conditions — soil, slope, crop being grown, climate, water quantity/quality, etc. — must be available and capable of applying water to meet the intended purpose.”
IWM, he says, increases the management of irrigation systems and methods, typically by combining several individual elements into a comprehensive strategy.
Some of the typical management strategies used in the Mississippi Delta include:
• For all irrigation types: Water measurement (flow rates/volumes), timers/pump automation, irrigation scheduling methods, soil moisture monitoring (for flood irrigation, this may be visual observation of the flood);
• Furrow irrigation: Polypipe hole sizing method (Phaucet or equivalent), surge/cutback irrigation, furrow diking;
• Flood irrigation: Zero grade, multiple side inlets, rice markers;
• Center pivot: Drop nozzles, re-nozzling (example, low pressure, reduced application intensity);
• Aquaculture: Split pond method, 6/3 water management.
A number of items should be considered when planning irrigation water management, Rodrigue says.
“Consideration should be given to managing precipitation effectiveness, crop residues, and reducing system losses. Also, modification of plant populations, crop and variety selection, and irrigated acres to match available or anticipated water supplies.”
And he says, producers should avoid traffic on wet soils in order to minimize soil compaction, and consider improving the irrigation system to increase distribution uniformity of irrigation water application (example, polypipe hole sizing).
“At a minimum, each water source should be evaluated yearly for pump output/water measurement,” he says. “This should be done at each outlet point/riser. This measurement can be used to evaluate how much/how long to irrigate.