Analyzing Irrigation Efficiency from All Angles

Xin Qiao, an Irrigation Management Specialist at the Panhandle Research and Extension Center at the University of Nebraska-Lincoln, has been busy developing and implementing new research projects to help improve agriculture and cropping systems in Nebraska.  Qiao and his research team have been implementing three collaborative irrigation management projects that are helping farmers understand the effectiveness of their irrigation and implement new irrigation best management practices for the future.

Nitrogen treatments on Sugar beet at 33% of full irrigation level.

Nitrogen treatments on Sugar beet at 33% of full irrigation level. On the left side of picture, sugar beet are applied 0 lbs of nitrogen, on the right side of picture, sugar beet are applied 180 lbs of nitrogen

One of Qiao’s research projects focuses on integrated water and nitrogen management for sugar beets and corn. According to Qiao, the impact of irrigation and nitrogen management on sugar beets and corn production have been well studied and quantified separately for decades in western Nebraska. Qiao’s research looks at the intersection of these two factors. Prior research has found that under-irrigation can limit optimum crop N uptake and over-irrigation can cause nutrient leaching below the root zone. Qiao’s research aims at discovering the perfect balance of irrigated water and nitrogen input.

The team will investigate crop response to combinations of treatments by looking at soil moisture profiles, drone spectral images and lysimeters. Qiao and his team hope the project will help instruct farmers how to better manage water and N together.

Another study Qiao is facilitating is the utilization of canopy temperature for dry bean irrigation scheduling. Dry edible beans are a common crop in western Nebraska and many farmers have adopted technologies such as ETgauge and soil moisture sensors to calculate their irrigation needs. However, both technologies have limitations, ranging from only measuring crop water indirectly to the high cost of these sensors for farmers.

Sensor complex

Sensor complex (data loggers, solar panels, and IRTs installed at dry bean field)

To tackle these limitations, Qiao and his team are using canopy temperature, measured by Infrared Radiometry Thermometer (IRT), to calculate crop water stress indexes such as CWSI (crop water stress index) and temperature-time threshold (TTT) for dry edible beans. This technology directly measures water stress, and direct contact with the crop isn’t necessary for measurement. While this technology has been studied on crops such as sorghum, corn, cotton, and sunflower, no study has been done for dry edible beans grown in western Nebraska. Qiao and his team are in their first year of conducting this experiment and the goal is to determine whether it can be used for dry bean irrigation scheduling.

Qiao is also working with Extension colleagues to investigate the effectiveness of speed-controlled variable rate irrigation (VRI) technology on crop production at farm fields with spatial heterogeneity. Qiao and his team initiated a collaborative Extension project with the Panhandle Research and Extension Center of the University of Nebraska-Lincoln, the North Platte Natural Resource District, 21st Century Equipment, Elite Ag, and three farms in the Panhandle area of Nebraska to look at the benefits of using speed-controlled VRI and soil moisture probes.

The participating farmers’ fields are highly variable in topography and soil texture. Uniform irrigation on these fields tends to create runoff where the elevation drops and water ponding at field low spots. Each field was divided into two areas, where half has a changed irrigation prescription related to data on the soil moisture profile, while the other half remains a control. Soil moisture profile, nutrient leaching, and crop growth are being monitored and compared throughout the growing season between the divided fields.

Extension specialists, government staff, industry professionals, and farmers are analyzing and discussing the problematic areas in these fields by looking at EC maps and historical yield data with the goal of investigating the effectiveness and potential benefits of speed-controlled VRI.

Xin Qiao, University of Nebraska-Lincoln

Xin QiaoDr. Xin Qiao, irrigation management specialist in Panhandle Research and Extension Center of University of Nebraska-Lincoln. Qiao got his Ph.D. in Clemson University in 2015 and his current research focuses on irrigation scheduling, soil water monitoring, and crop water stress monitoring in western Nebraska.


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