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
STONEVILLE, Miss. -- Alternating wet and dry production is a radical new way to grow rice, and some Mississippi producers are finding the idea not only seems feasible in theory, but also works well in practice.
Jason Krutz is an irrigation specialist with the Mississippi State University Extension Service and a researcher with the Mississippi Agricultural and Forestry Experiment Station. He said the technique, known as AWD, grows rice without standing water, which reduces water use by about a third while also maintaining yields.
STARKVILLE, Miss. -- With spring around the corner, gardeners and farmers are beginning to plan for the upcoming planting and growing seasons.
One important way to ensure success during the Mississippi growing season is to have a plan for irrigation. Water keeps plants alive during the hot Mississippi summers, so irrigation is often vital during times of limited rainfall.
STARKVILLE, Miss. -- Dry September weather has Mississippi soybean producers on opposite ends of the irrigation spectrum: Some are done, while others want to water one more time.
Jason Krutz, irrigation specialist with the Mississippi State University Extension Service, has a question for them: What do the soil moisture sensors say?
STONEVILLE, Miss. -- About 190 people gathered Tuesday to focus on water use and conservation, a showing that demonstrates just how important this topic is to the Delta and state.
The Delta Sustainable Water Resources Task Force convened the 2015 Mississippi Delta Irrigation Summit in Stoneville. The event drew farmers, consultants, industry suppliers, university researchers, Extension agents and U.S. Department of Agriculture officials from Mississippi, Arkansas and Louisiana.
STONEVILLE, Miss. -- Row crop producers who irrigate their crops can learn the benefits of soil moisture sensors during two separate field days planned for July and August.
Jason Krutz, an irrigation specialist with Mississippi State University, said farmers can learn about the advantages of using soil moisture sensors to determine when to irrigate.
Participants also can see the devices in action. Product demonstrations by manufacturers and distributors will showcase types of sensors, features and costs.