Irrigation
Most crops can utilize about 2.5–3 feet of soil profile to extract moisture. This gives a growing plant about 2.5–3.5 inches of available water to carry it without additional rainfall. Emerging crops use very little moisture early in the season, and a good profile of moisture will carry these plants for about a month without supplemental moisture.
As the crops get larger and begin to canopy, a full profile will only last about 8–14 days. This typically begins to occur in early June through August. Rainfall is the best hope for supplemental moisture since it is free, but it is not 100 percent effective. As soils seal over from rain or irrigation, they take water slower, thus making rainfall less effective. Determining how effective a rainfall is should be done with a soil probe, shovel, or some type of device to determine how deep the moisture soaked. Hard, fast rains can run-off as much as 75 percent of the water, where a slow steady rain can soak as much as 90 percent. The type of rainfall event will determine its effectiveness as well as the amount of moisture already in the soil.
Tillage will often dry out the soil surface as deep as 2–3 inches, but doesn't really effect the deeper moisture. Rainfall is the best choice for replenishing the shallow moisture early in the year, but irrigation may be required during the summer months. Supplemental irrigation is not typically needed until mid to late June on most crops under normal rainfall conditions. However, it is never too early to get prepared for irrigation, even if it is early, because it will certainly be needed in July and August to meet crop demand.
Common Conversions:
450 GPM = 1 acre inch per hour or 1 cubic foot per second (cfs)
1 gallon = 8.33 pounds
1 cubic foot = 7.48 gallons = 62.4 pounds
1 acre-inch = 27,000 gallons = 1 acre flooded one inch deep
1 acre-foot = 12 acre-inches = 43,560 cubic feet = 325,900 gallons
1 gallon = 3.785 liters = 0.003785 cubic meters
1 cubic meter = 1000 liters = 264.2 gallons
A column of water 2.31 feet high exerts a pressure at the base of one psi
1 psi = 2.31 feet of vertical elevation change for water.
1 atmosphere = 14.7 psi = 33.95 feet of water
1 inch of mercury = 1.13 feet of water
Publications
News
STARKVILLE, Miss.-- A new online resource is helping agricultural producers find technologies to improve water conservation on irrigated land.
The Mississippi State University Extension Service is among four land-grant universities collaborating on this web page, which is available at http://surfaceirrigation.extension.msstate.edu. The page hosts dozens of publications and videos related to irrigation, as well as product demonstrations.
STARKVILLE, Miss. -- The Mississippi State University Extension Service will offer multiple opportunities March 3-5 for Delta row-crop producers to get help with an important irrigation planning tool.
Success Stories
Delta soybean producer irrigates his fields, increases yields
Most of the Delta is already irrigated, but not all farmers are taking advantage of the latest irrigation technologies. However, agents with the Mississippi State University Extension Service are increasing Delta producers’ knowledge— and application—of new, more efficient ways to water the rows.
Delta farmer Travis Satterfield reflects on 40+ years in the fields
The price of rice hasn’t increased much since Travis Satterfield of Benoit began growing it in 1974, but nearly everything else in the world of production agriculture has changed.
2020 Pearl River Clean Sweep removes thousands of pounds of trash
Since it began 4 years ago, the Pearl River Clean Sweep has removed more than 135,000 pounds of trash from the Pearl River Basin, including the Pearl, Strong, and Bogue Chitto Rivers across 15 Mississippi counties and two Louisiana parishes.
The Clean Sweep offers an opportunity for volunteers to participate in a coordinated effort organized by like-minded leaders. Many people affiliated with the Mississippi State University Extension Service participated in the 2020 cleanup, and lead organizer Abby Braman is an Extension-certified Master Naturalist volunteer.
In this "What's New in Extension," Extension agents implement better safety standards, train to deliver Mental Health First Aid, and receive national recognition. Also, new irrigation and specialists join the Extension family.
On his Rolling Fork farm, Bill Rutherford is living the life he dreamed of as a child. (Photo by Kevin Hudson)
