To water or not water? Many farmers grapple with this issue every year. Row cropping itself can be a tedious and complex art form, but when it comes to irrigation it’s all about strategy.
According to the 2012 U.S. Census of Agriculture, there are approximately 26,000 acres of corn irrigated for grain in Alabama. Most farmers choose to irrigate for two reasons: increased yield and reduced risk during a drought.
Regional Extension Agent and Irrigation and Water Management Engineer, Anis Bouselmi said, “There are several different types of irrigation systems available and each type offers advantages and disadvantages to the various crops and land types.”
Irrigation systems can be classified into three categories:
- Surface irrigation: it is one of the oldest methods, but is not as efficient as some other options, because there is a tendency to use too much water to saturate crops.
- Spray Irrigation: The water is led to the field through a pipe system in which the water is under pressure. The spraying is accomplished by using several rotating sprinkler heads or spray nozzles.
- Drip Irrigation: delivers water to the roots of the plants, on a drop by drop basis. That makes it one of the most efficient irrigation systems that you can possible use, since it is able to minimize any runoff or evaporation.
But the most commonly used system among Alabama farmers is a Center Pivot System. By using this system, water is dispersed through a long, segmented arm while covering a quarter mile radius.
Like most farm equipment, these systems do not come cheap. The main expenses farmers face include well installation, pumping stations, in-ground pipe for water transport, and water application equipment such as a center pivot system. Pumping and applying water requires a large amount of energy resulting in electric or diesel expenses. Other expenses include land rent or purchase, labor and capitol costs.
Since the water being distributed is coming from underground springs, the farmer must be aware of the quality of water given to the corn.
Greg Pate, director at EV Smith Research Center, had his own comments on the quality of water and its effect on corn production.
“Most of the water in Alabama is well suited for irrigation,” Pate stated. “However, there are pockets within the Black Belt region that can have water with high levels of dissolved salts. Also, water from stagnant swamps can have issues with pH.”
According to the 2012 US census of Agriculture, irrigated corn will average approximately twice the yield compared to dry land acreage. Farmers of the previous generation will often use the method of “letting the corn tell me” when it is time to irrigate but today that’s not the case. Most farmers have gone to a scheduling system to encourage optimal bushel production each year.
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If a farmer makes the choice to irrigate their corn, the next question is how much water and how often.
“Knowing the water status of the soil, is fundamental to agricultural water management,” said Bouselmi. “Current methods (Watermark® sensors, capacitive sensors …) are used to measure the moisture in the soil at different depths. Investment in this material, long as it is well placed and that we know to interpret the curves, can predict and better manage the irrigation.”
“Maximum water usage occurs at tasseling and silking (R1 stage),” Pate said. “However, adequate water must be available from the mid vegetative stages (V6-V8) and continue throughout the kernel filling process (R5.5).”
After the kernel filling process, irrigation should continue until the plant reaches physiological maturity. This stage is known as Rb or Black Layer. It is signified by the formation of a black layer of cells at the base of the kernel.
“We never know the worth of water ‘til the well is dry.” – Benjamin Franklin.
For more information on corn irrigation, contact your county Extension agent.