A Combined Effort

Precision Agriculture Takes a Closer Look

Seven researchers and a farmer stand in the middle of a cornfield one hot August afternoon on a farm near Brush. Each of them sees something a little different. One grabs a leaf and begins inspecting it, while another peels back the husk of an ear of corn. Others open the control panel on the sprinkler system and look inside. Some poke around at the soil. This group of more than 30 Colorado State University and USDA Agricultural Research Service scientists are part of an interdisciplinary team the Colorado Agricultural Experiment Station has assembled to find out how the latest technology can be used to farmers' advantage.

Farmers have always known that various parts of a field produce different crop yields. Regardless of the variability, they really had no choice but to treat an entire field the same with respect to applying fertilizer, water, herbicides, and pesticides. "A farmer may see an area that is beginning to wilt," says Dwayne Westfall, a Colorado State soil and crop scientist. "It may just be a sandy area, but he will irrigate the whole field with more water than is needed on most of the field, when in fact, he should reduce the application depth to what can be held by the sandy soil." However, that management strategy may be changing with the advent of precision agriculture–tools and techniques such as global positioning systems, geographic information systems, remote- sensing technology, yield monitors, grid soil sampling techniques, computer models, and variable rate applicators.

These precision farming technologies are being promoted as the solution to crop yield variability. "The problem is the industry is way ahead of the science," says Dale Heermann with the ARS, Water Management Unit. There hasn't been enough research done to tell what the real issues are that result in yield variability.

But this multidisciplinary team of Colorado State scientists, extension agents, ARS Water Management Unit scientists, graduate students, industry partners, and cooperating farmers all are studying the same fields and comparing data to understand the causes of yield variability and see if precision agriculture offers economical and environmentally beneficial solutions.

"Our study in Colorado is unique," says Raj Khosla, precision agriculture specialist at Colorado State. "We take a systems approach in the use of precision technologies to make better decisions." The concept of this technology is not just the use of high-tech, precision agriculture tools, but rather the economical use of those tools that also results in environmentally friendly farming systems.

The scale of the project and the close collaboration of ARS and Colorado State scientists on the project are unique as well. All of the researchers are applying their expertise to actual farm fields. "The Colorado Agricultural Experiment Station funding has allowed us to move some of our research projects from a small scale, 20 by 30 feet in size, to fields as large as an entire 175-acre center pivot field," says Philip Westra a Colorado State Weed Scientist. "The scale is at a much higher level than what we typically use as individual researchers." Farmers appreciate this approach since it makes the research more valid in their real-world situation.

"Most research is single-discipline oriented," says Heermann. "We scientists tend to learn more and more about less and less. By working together, we bring our combined expertise to bear on experimental design and analysis, and we reduce the risk of tunnel vision." The precision agriculture team members also get the benefit of combining several scientists' worth of data into their work. "Every year, we learn something new," says Westfall. "That's what research is all about."

The researchers are using the advanced technologies and research methods in addition to farmers' experiences with their fields to determine what is really going on and what can be done to fi x it. "This project is looking at the integration of all of the management factors and identifying how they affect the fi nal yield," says Westra. "Yield is what the farmer is most interested in, so we're using new precision farming tools to create data layers for weeds, diseases, insects' fertility, irrigation, and other variables to figure out how they overlap and combine to affect yield in various parts of the field."

The geographic information systems, concept of data layers makes it possible to see where the factors a farmer has to deal with overlap and interrelate. A key element of the study is to determine the unit of variability that is reasonable for a farmer to manage. Early use of precision agriculture relied on intensive grid sampling. This approach proved to be too costly, particularly on crops with limited cash flow. Using remote sensing, the farmer's production experience, and statistical methods used in natural resource applications, the team has moved to a concept of production-level management zones.

By correlating data layers the team divides a field into management zones based on crop productivity: high, medium, and low, for example. The farmer's insight is an important component."We are cognizant that the farmer knows which parts of his field are high production and which are low," says Westfall. "We are trying to integrate all of our information together, with heavy reliance on the farmer's experience."

The theory is that when management decisions are based on productivity zones, a farmer can make the most economical use of techniques of applying water, nutrients, herbicides, pesticides, and other inputs. In the past, a farmer may have been tempted to spend significant amounts of money on an entire field including parts of a field that were not going to be productive, no matter what.

Using precision farming techniques, a farmer can identify parts of the field that need special attention. The farmer can then decide if an input will be cost-effective, given what the zone will ultimately produce.

The multidisciplinary approach fostered by the Colorado Agricultural Experiment Station and the Agricultural Research Service is the key to both creating the data layers and evaluating their relationships. For example, the researchers are finding relationships between soil type, fertility, and weed and insect infestation. A major component of this project is determining what drives these overlapping field relationships.

Weed scientists like Westra are looking at the spatial distribution of weeds and how they can be combated. At the same time, ARS scientists led by Heermann are evaluating technologies such as AccuPulse for delivering fungicides with irrigation systems. This system is unique in that it uses the existing center pivot to get around the field, but its delivery system is independent of irrigation piping, unlike chemigation systems. Therefore, the chemical is prevented from flowing back into the well, and a higher concentration of product can be applied since it is not diluted with irrigation water; and it can be applied exactly where needed. The ARS scientists also are researching the use of soil electrical conductivity technology for mapping soil types and the use of remote sensing to determine the crop's nitrogen status.

Plant pathologist Howard Schwartz is studying the spatial characteristics of plant diseases and testing treatments for the diseases. Colorado State entomologist Frank Peairs is providing data on insect activity. He and a staff of research associates and graduate students monitor traps for such pests as European corn borer, western bean cutworm, and western corn rootworm. Khosla and Westfall are working on managing nutrients. They use high-tech approaches such as monitoring chlorophyll content and leaf area spatial variation to evaluate the effectiveness of nutrient application.

Tim Green with the ARS is studying the advantages of variable-rate seed planting for dryland systems. Weather data at the research fields, including solar radiation, temperature, wind run, vapor pressure, and precipitation, are collected and correlated. Precision agriculture project manager Kim Fleming; Raj Khosla, precision agriculture state specialist; and Cooperative Extension Agent Bruce Bosley are working to get farmers involved and transfer the results of the project to them.

Evaluating the economics of precision farming is a necessary component of the project. "If a farmer cannot make money with precision agriculture, he's not going to adopt it," says Westfall. However, what may not be economically feasible today may become a necessity in the future. Farmers can see the day coming when they may be legislated into using only a certain quantity of nutrients, herbicides, or pesticides on their farms. It will be up to the farmer to figure out where and when to best apply them.

Precision agriculture may make a huge difference in both the decision and the application. "The only thing that hasn't gone up triple or quadruple in the last 20 years is the price of corn," says Larry Rothe, a cooperating farmer from Wiggins. "Our only chance is to figure out how to do it with less money."

An additional commitment to precision agriculture by Colorado State is the creation of a new degree concentration: Applied Information Technology in Agriculture in the Department of Soil and Crop Sciences. Undergraduates are trained in both technology and agriculture in this unique program.

"I think precision agriculture is the wave of the future," says Westfall "We just don't know what it will end up looking like in another 10 years. It may be something we can't even envision today, but it is here to stay."