Research Update

Using Aerial Imagery to Map Moisture Stress and Install In-ground Sensors

Authors: Travis Roberson, David McCall, Ph.D., Chase Straw, Ph.D. (Texas A&M)

Water is our world’s most vital resource and is crucial for all life on Earth. The use of water on golf courses is essential to maintain high standards. Within the United States, approximately 6 trillion gallons of water were consumed across 21,000 golf courses for daily management of areas such as tees, fairways, and greens in the year of 2014. However, this high-water usage on golf courses creates controversy because of limited tangible benefits, such as yield associated with most agricultural crops. For this reason, golf courses receive a negative stigma, especially during periods of prolonged drought conditions. However, most golf course superintendents adopt management practices and technologies to aid in irrigation management decisions, resulting in reduced water use. Golf course superintendents have seen drastic advancements in irrigation software, drought tolerant cultivars from breeding programs, water budgeting, converting acres to native areas, implementing soil moisture time-domain reflectometers (TDR), among other strategies over recent decades. These practices tend to be localized to certain areas across the golf course and do not encompass the property as a whole for daily management decisions. Monitoring large acreage areas of turfgrass is best seen from a ‘birdseye’ view. The use of drones equipped with special sensors is expanding rapidly and may aid in soil moisture monitoring. Previous research has shown a high correlation between visual, near-infrared, and thermal imagery and turfgrass under significant drought stress within smallplot field and greenhouse research. Despite substantial advances in soil moisture monitoring research, many concepts fail when scaled across large acreage because of convoluting aspects like surface topography, soil texture, and other extraneous factors. The overall goal is to spatially map both aerial estimations of drought stress and static environmental conditions (topography and underlying soil characteristics) across multiple dry-down cycles. This information will allow us categorize site specific management zones across large acreage to group irrigation heads into prescription zones. Within these zones, we will also identify specific coordinates of the most optimal locations to install wireless soil sensors. These sensors will allow real-time feedback through continuous soil moisture data tracked throughout the study. We will track the total amount of water applied for comparison between fairways with management zones and sensor technology and others managed based on typical evapotranspiration (ET) based watering. Our hope is this research will improve the irrigation efficiency across golf courses beyond simply relying on ET data that does not account for variability across micro-environments.