Study will illuminate precision ag
Jan 16, 2002 12:00 PM, By Elton Robinson Farm Press Editorial Staff
To fully understand the value of precision agriculture, farmers must first “get the picture.”
One “picture” of course, refers to the images farmers need to make precision agriculture work, like aerial photographs from the Farm Service Agency, multiple-year yield maps, electrical conductivity maps that relate to soil differences and topographic maps with elevation accuracy within an inch.
“But farmers must also understand the big picture — how to use this complex technology to improve their bottom lines,” says Harlan Palm, a University of Missouri, Columbia, research assistant and professor.
Palm has just received a $1.2 million federal grant to develop guidelines for the adoption of precision agriculture by farmers. Partners in the study include MU, the University of Illinois and the Potash and Phosphate Institute at the Foundation of Agronomic Research.
In the 40-month study which begins this winter, researchers will select four fields of 100 acres or less in Missouri and Illinois for demonstrating the collection and processing of the historical data and sensor-based soil and landscape information at the core of precision agriculture.
The data will be collected by sensors on fixed-wing aircraft and satellites provided by the National Aeronautics and Space Agency. Bare soil and crop reflectance data will be processed into imagery for determining management zones and for in-season crop monitoring.
Management zones are the new buzzword in precision agriculture, referring to the division of a field into zones, each with similar characteristics and yield potential. For example, one management zone might consist of an area where soil type is similar.
Depending on the producer's interests and machinery capability, customized management plans can be put in place, including variable seeding rates, tillage and targeted soil sampling.
Funds will also be used to further develop a decision-aid software program, Management Zone Analyst, developed at MU for applying precision agriculture principles.
Palm admits that not many Missouri producers are using precision agriculture — that it's limited to early adopters and innovators. But these farmers will help sort out the most practical applications and even discover new uses of the technology.
“Our goal is to create information-intensive management that will allow smaller and mid-size producers to increase profitability. We feel that precision agriculture holds great potential for benefits to the environment and for economic gains to the farmer,” said Palm, who believes the study will have applicability way beyond the two states.
One of the more interesting aspects of the study is the use of electrical conductivity to attain imagery. The principle of the technology is that voltage is projected into the soil profile. Since conductivity changes according to soil texture, the technology can be used to help researchers determine soil type variance in a field, according to Palm.
While the measurement of electrical conductivity is expensive, Palm notes that “it is a one-time measurement. It's not apt to change over time, unless there is extensive movement of soil.”
The study will also use GPS technology to construct topographical maps of fields. Today, this elevation measurement is accurate to within one inch, according to Palm.
Existing aerial maps and historical photos are also important and are considerably cheaper to obtain.
Can most variability in yield be explained through elevation maps and soil type maps?
“That's the $64,000 question,” Palm said. “It's an elusive question because of the weather. No two seasons are identical. And when you look at yield maps of a particular field, at times it looks like a different field. A lot of that can be explained because of the variance in weather.”
No doubt weather can throw precision agriculture farmers and researchers a curve, Palm says. “A thin soil where the soil conductivity index may be lower could end up being the best-yielding soil one year because it was wet during critical times of the year. Then again, the probability of that happening may be low.”
Perhaps precision agriculture could help the farmer document the aforementioned probability, Palm says. “We can help the farmer make better decisions through having better knowledge. Hopefully, it can be cost-effective for them, maybe increase their productivity and also be better for the environment.”
While the study can bring a lot of information to the farmer, it's going to be up to individual farmers to fine-tune precision agriculture techniques and perhaps even find new uses for the technology.
“I was attending one conference where a farmer just surprised the whole audience by saying that he was getting higher yields in poorer-yielding areas by going in with a higher seeding rate in soybeans. The plants may have been smaller, but there were more of them.
“Farmers will sort these things out,” Palm said. “That's the bottom line. What we can do from a university standpoint is share the research learning with them to this point, bring them up to speed on the cutting edge technology. The farmers will pick up on the things that fit their enterprises and are cost-effective.
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