Autosteer technology with GPS can achieve one-centimeter accuracy when planting, applying fertilizer, or spraying herbicides, explains USDA researcher Amanda Ashworth in an undated interview with the Agricultural Research Service (ARS). According to Ashworth, this tractor guidance technology can be profitable for small operations and improve efficiency gains by 20 percent. About half of large U.S. row-crop producers use the technology, while small farms rarely implement it, adds her colleague Philip Owens in the interview.
What precision agriculture means
Ashworth defines precision agriculture as a collection of tools that use satellite navigation like GPS or GNSS to respond to differences within fields through plant stand management. This includes variable rate application technology, which allows farmers to distribute different amounts of fertilizer within a field, and yield monitoring systems that record crop and moisture data during harvest. Higher precision from GPS-guided tractors can reduce overlaps with double application and missed areas, thereby improving overall economic and environmental efficiency, Ashworth explains. According to Owens, the concept itself has existed for decades, but practical tools are increasing exponentially. The role of science is to bundle these tools and evaluate their effectiveness.
Who adopts the technology and who doesn't
According to Owens, approximately half of large-scale row-crop producers in the United States use tractor guidance, while small operations have largely not adopted the technology. Yet small farms make up more than 85 percent of all U.S. farms, as Owens explains in the interview. Large farms are expanding their use of precision agriculture and overcoming technical hurdles. The team of Ashworth and Owens focuses specifically on small farmers and tractor guidance systems.
What small farms could gain
Tractor guidance enables spatially more precise fieldwork, which according to Owens can lead to less operator fatigue, higher yields, and longer working days in difficult conditions. Together, these effects could significantly reduce small farms' fuel, labor, repair, and maintenance costs, Owens continues. The technology can pay for itself relatively quickly through reduced diesel, fertilizer, and other input consumption, Ashworth adds. If overlaps and gaps in poultry manure or inorganic fertilizer application are reduced by 20 percent, this would have significant water quality benefits by reducing nutrient runoff, Ashworth explains. Her team is investigating actual reductions in overlaps and gaps plus their economic and environmental effects, and has developed the decision tool "Tractor Guidance Analysis" with Mike Popp from the University of Arkansas.
Comparison: What targeted irrigation already shows
Progress in irrigation, drainage technology, and decision support are among the research accomplishments of fiscal year 2020 reported by USDA ARS. In Bushland, Texas, researchers compared water use and yield of grain corn and sorghum using subsurface drip irrigation and sprinkler irrigation. Drip irrigation reduced corn water use by up to 6 inches, increased grain yield by up to 20 percent, and improved water productivity by up to 46 percent compared to sprinkler irrigation. How irrigation methods affect water productivity is simultaneously described by ARS as not well understood. In Parlier, California, a ten-year field study on deficit irrigation in peach production showed water savings of up to 40 percent without significant yield or fruit quality loss. The peach findings apply to arid conditions, and ARS describes long-term deficit irrigation effects on productivity as not well understood. A comparison by the International Atomic Energy Agency from 2007 quantifies the savings potential more dramatically. In cotton production in Syria, drip irrigation could save more than 60 percent of irrigation water over the first three months of the growing season compared to surface irrigation. More broadly, the International Atomic Energy Agency estimates potential savings through drip irrigation compared to traditional flood irrigation at approximately 25 to 50 percent of irrigation water, coupled with 20 to 50 percent higher efficiency of applied fertilizer and less nitrogen leaching.
Where the technology reaches its limits
The technology can pay for itself relatively quickly as Ashworth describes it. Small farms may not be able to distribute costs the way large operations do, as Owens explains. Owens announces further research in the interview, such as how field irregularities and terrain features like slope affect overlaps in tractor guidance. The editorial on sustainable crop production emphasizes that for progress in sustainable crop production, agronomic, ecological, and socioeconomic aspects must be considered together according to local conditions.