• By Haleigh Erramouspe •
Fields of cotton, wheat, sorghum and other crops are a common sight in the Texas High Plains, but what you might not expect is to see drones whipping through the air above these fields.
However, if you drive out to a field of cotton about 30 miles north of Texas Tech University, that is exactly what you might see.
Wenxuan Guo, an assistant professor in crop ecophysiology and precision agriculture in Texas Tech University’s Department of Plant and Soil Science, is using the drones to study the effects of variable-rate irrigation in cotton yields.
“We know in this area water is the No. 1 limiting factor for agricultural production,” Guo says. “One of my top priorities for research is to use less water and get the same amount of production or use less water to have an optimized production.”
Guo came to Texas Tech University in 2016, and since then he has worked to discover methods of water conservation and efficient water use using precision agriculture technologies while still optimizing yields.
This soon led him to working with South Plains Precision Ag in Plainview, Texas. The company has a variable-rate irrigation system, which allows farmers to apply the right amount of water in the right area at the right time in their fields.
However, current challenges in variable-rate irrigation in this area involve knowing the timing, location and rate of water application to optimize production. Guo says solving this issue became the goal of his research.
Throughout 2017, Guo and his research team applied three different rates of irrigation across a 480-acre cotton field to discover how the crop would respond at different landscape positions of the field.
Drones Play Key Role
Studying the responsiveness of the different areas, says Guo, is where the drones played a key role. He would fly the drones equipped with various sensors about 60 meters above the plant canopy. Through the sensors, Guo and his research team were able to measure and identify the spatial variability for plant growth, as well as the soil moisture within the field.
Guo says they discovered variability in several agronomic factors that affected how well the crop responded to different amounts of irrigation. These factors included soil properties and topography — soil texture, organic matter, elevation and slope. They discovered cotton yield responded well to irrigation in areas with flat land and fertile soils, but it did not respond well to irrigation at areas with high slope and sandy soils.
Because of their varied responses to irrigation, these agronomic factors were shown to affect yield potential in those different areas of the same field. By applying less irrigation to areas with high slope and sandy soils and areas without crops, farmers can use less water and get the same or a better return on their investments.
“Those factors all affect the water availability for plant growth and also the final yield,” Guo says. “If we adjust our allocation of irrigation water, matching the yield potential in the field, our water use efficiency will be optimized.”
Factor In Variability
Guo says this research could prove to be beneficial for farmers who produce various types of crops. He knows many types of agricultural fields have a substantial amount of variation in soil properties and topography and recognizes this research could apply to other crops in the future.
Using precision agriculture technologies to identify and measure variability could lead to farmers in the community using less water and more sustainable agriculture in the region.
“Based on this study,” Guo says, “we can design a strategy to optimize the allocation of irrigation water in the field to save water or improve water use efficiency. The result would be better profitability for the farmer.”
Haleigh Erramouspe is a student at Texas Tech University. Contact Wenxuan Guo at firstname.lastname@example.org.