Irrigators conserve water by checking water in root zone

By Sun Advocate

With reports of a low water year, water conservation is on the minds of many people in the Castle Valley.
For those in the agriculture industry, making the most of what water is available is a critical part of business. The best method of determining the water needs of crops is to find out how much water is in the soil or root zone of plants prior to irrigation.
The storms of last fall filled the soil at that time and some of that water is still in the soil and available for plant growth this spring.
Knowing how much water is in the soil prior to irrigation will assist crop producers in determining the amount of water, in inches, that needs to be applied to fill the soil profile.
This can save water because often the amount needed to be applied is less than the amount of water that would be applied during a “full” irrigation, especially in the spring when temperatures are cool.
For instance, instead of running a sprinkling system for the recommended 12 or 24 hours (a full irrigation) producers may need to run them less time to fill the soil profile again. This is where water is saved.
The best time to do this type of moisture analysis is prior to each irrigation. If this is not possible, a crop producer should at least check soil moisture in the spring, prior to irrigation and again in the fall after the last irrigation.
To determine how much water is in the soil, auger down into the soil and use the “moisture by feel” method at each foot of depth down to the depth of the plant roots.
Some producers have moisture sensors installed in their fields by the San Rafael or Price River conservation districts. These sensors do the same thing as augering into the soil.
Alfalfa has a rooting depth of five ot six feet; small grains, three to four feet; and pasture grasses have a rooting depth of approximately 30 inches depending on how they have been grazed. Lawn grasses have a rooting depth of approximately 12 inches.
The local conservation district, Utah State University Extension, and Natural Resources Conservation Service offices have information on how to calculate soil moisture.
Also watch for Irrigation Water Management Workshops coming in May and August or September.