Four Irrigation Systems Part Of Study At Bushland

June 9, 1997

FOUR IRRIGATION SYSTEMS PART OF STUDY AT BUSHLAND

Writer: Pam Dillard, (806) 359-5401, [email protected]
Contact(s): Terry Howell, (806) 356-5746, [email protected]; and Arland Schneider, (806) 356-5732, [email protected]

BUSHLAND -- Starting this year, two agricultural engineers at the USDA-Agricultural Research Service Conservation and Production Agricultural Research Laboratory are gathering data to compare the efficiency of low-energy precision (LEPA) and low-elevation spray (LESA) application devices with the more common overhead spray heads.

"The 1996-97 wheat year is the first leg in this study, so no results are available yet," said Dr. Arland Schneider, who with his colleague, Dr. Terry Howell, are the principal investigators doing the work. A similar study using soil water measurements to schedule the full irrigation is complete, and publications describing the results are available.

"We're using the wheat evapotranspiration (ET) data coming from the North Plains PET Network of computer-driven weather stations located around the Panhandle to schedule full and deficit irrigation of TAM-202 variety wheat," Howell said.

For full irrigation, daily wheat ET and rainfall are entered into a water budget to calculate the amount of irrigation water. One- inch irrigations are then applied to make up the difference between ET and rainfall. Deficit irrigation treatments receive 75, 50, and 25 percent of full irrigation needs on the same day. A non-irrigated, zero percent treatment is also included for comparison.

"We measure soil water in the fully-irrigated plots to verify the accuracy of the wheat ET estimates," said Schneider.

All irrigation amounts are being applied with four sprinkler methods that include using 360-degree spray heads to meter water to double-ended socks (LEPA) on the ground, LEPA bubble, above-canopy spray units at about 2.5 ft. above ground (LESA), and overhead spray heads about 5 ft. above the ground with convex spray plates. All devices are spaced 60 inches apart on a three-span lateral move irrigation system.

The scientists say the deficit irrigation treatments will show the efficiency of fractional amounts of ET applied to wheat during the spring irrigation season.

-30-