Writer: Pam Dillard, (806) 359-5401, p-dillard@tamu.edu
Contact(s): Judy Tolk, (806) 356-5736, jtolk@ag.gov
BUSHLAND Looking for ways to increase producer profits while conserving environmental resources drives modern agricultural science, say a trio of USDA Agricultural Research Service (ARS) researchers at the Conservation and Production Laboratory at Bushland.
Drs. Judy Tolk, plant physiologist, Steve Evett, soil scientist, and Terry Howell, agricultural engineer, have combined their individual expertise in an unusual outdoor laboratory to study crop production.
For some travelers on Interstate 40, the metal building in the field at the northwest corner of the station may not seem unusual. But the Soil-Plant-Environment Research facility, or SPER as the scientists call it, enables the trio to conduct some highly specialized studies on how environment, management practices, crop characteristics, and soil properties control crop growth and yield.
What’s special about the SPER is its 48 lysimeters, which are large boxes of earth, measuring 2.5 feet by 3.3 feet with a depth of 8 feet. The units can be weighed to measure water loss.
The lysimeters contain three major soil types of the southern and central High Plains. There are two Texas soil types, a silty clay loam from Bushland and a fine sandy loam from Big Spring. The third soil is a silt loam from Garden City, KS.
“These soils differ by important soil characteristics such as water holding capacity, density, and amount and depth of caliche,” Tolk said.
Another feature of the specialized outdoor laboratory is its rain shelter — the large metal building which automatically moves down rails to cover the lysimeters when rainfall occurs. This allows control of the amount of soil water during an experiment.
“Irrigation research is one of our top priorities,” Howell said. “Nowhere in the United States is irrigation as threatened, as well as the rural communities whose economies depend on irrigated agriculture, as it is in the southern High Plains.”
From 1994 to 1996, the scientists planted short-season corn in the big boxes to evaluate the grain yield resulting from limited to full irrigation.
“We found the corn grown in the silt loam or Kansas soil, produced the highest corn yields under all conditions,” Tolk said. “Under full irrigation, the corn in the clay loam produced yields similar to the crop in the silt loam. However, the corn yields were greatly reduced under dryland conditions because the crop failed to extract some of the available water at depths below four feet, unlike the crops in the other two soils.”
“The corn in the sandy loam had less yield less than in the other two soils, even under full irrigation, which was possibly due to the lower water-holding capacity and high density which restricted rooting,” she said.
In 1997 and 1998, the scientists will be evaluating short- to medium-season grain sorghum, with irrigation treatments ranging from dryland to full irrigation. And, aided by the specialized environment of the SPER, these researchers will continue seeking solutions to age-old problems important to the agricultural producer.
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