Precision agriculture quantified Precision farming is not just a theory on Kenneth Hood's Perthshire, Miss., farms. This innovative, early adopter has tried it all, often working with prototypes as individuals, universities and companies put new products and theories in his hands for testing. Hood lists NASA, Mississippi State University, Case IH, Spectral Visions, USDA and others among his collaborators.

Over the last three years, Hood has tested grain and cotton yield monitors, GPS field mapping, precision soil sampling, near infrared photography from satellites and low flying aircraft, variable rate technology for seeding and applying fertilizers, herbicides, plant growth regulators and insecticides. He shared his experiences with farmers from across the South at the recent AgTech 2000 and Southeast Vegetable and Fruit EXPO in Greensboro, N.C.

Hood shared the podium with John Havlin, head of the soil science department at North Carolina State University, and Chad Dosch, a consultant with McLawhorn Crop Services Inc. in Cove City, N.C.

A wonderful thing "Technology is a wonderful thing," Hood says. "I think it's going to keep you and me in business in the future. The technology keeps getting better and more affordable. The first thing I would buy is yield monitors for all of my equipment. The yield monitors on my grain combines and cotton pickers show us yield variations in every field."

Hood uses a private plane to fly over and take infrared photographs of every field every week, giving him a running record of everything from crop stands to crop vigor, insect and weed pressure and even moisture stress.

"The infrared film can detect moisture stress a week or more before we can see any wilted leaves," he says. "That's the value of this technology. We need weekly photographs so we can detect problems and correct them before they cost us yields."

To any grower who might think farming is getting as easy as looking at photographs or computer analysis of fields and making accurate production decisions, Hood has these observations. "No computer is going to out-farm me. We do a lot of ground truthing, verifying and validating. Consultants check our fields twice every week. We plant map every cotton field every week. When we see something unusual on the photographs or on our yield monitors, we check it out. Then, when we make an application of any product, we go back to the field to verify the results. We are doing some pretty good economic studies."

With fields as large as 800 to 900 acres, Hood says the new technologies, for evaluating and precision applying products, are really paying off. A single mistake in an 800 acre field, he notes, can generate a significant yield loss or put excess nutrients or chemicals into the environment.

This past season he was ready to apply a defoliant to one large cotton field. Close examination of the latest infrared photograph showed half the field was mature, but the other half was still green.

Showed maturity "Remote sensing showed us the relative maturity of the cotton," he says. "We terminated the portion of the field that was mature, but we waited 10 days before we terminated the other side. We made an extra half a bale per acre on that last 220 acres just by waiting."

A review of records from the year before told Hood exactly why the 220 acre portion of the field was maturing later. He had peanuts on that field in 1999. Residual nitrogen from the peanuts was keeping the crop green longer.

He also used infrared photographs to identify heavy morningglory infestations in several of his fields. Once the spots were identified, Hood marked them on his computer maps. When the sprayer driver traveled over these fields, the computer automatically turned the sprayer on as it passed over the morningglories and off when no weeds were present.

"The sprayer driver didn't have to go up and down every row," Hood notes. "He looked at the map on the computer and drove to the spots that needed spraying. The variable rate sprayer did the rest."

Consultant Chad Dosch works with farmers in the environmentally sensitive Neuse River Basin in eastern North Carolina. Average field size of most of his clients is about nine acres. Since most of these farmers have been diligent about taking soil samples and following the recommendations for years, most of the small fields show relatively few variations in nutrient or pH levels. So, Dosch sees little need for precision soil sampling in 2.5 acre grids or precision nutrient or lime applications.

Instead, most of his clients elect to map field borders using GPS guided computer software. They then overlay digitized soil series maps over the field maps.

"We accurately locate streets, water control structures, wells, houses, ditches, ponds and other structures on these maps," says Billy McLawhorn, founder of McLawhorn Crop Services. "These maps are accurate enough so a farmer can lay a ruler on the map and figure out quickly how many acres are in each field.

Can catch problem "He can easily subtract all the areas where he will not plant or spread or spray. With that information so readily available, any of our clients can very easily catch a problem with sprayer or spreader or planter calibration."

When these consultants encounter a field of 15 acres or larger, or a field with significantly differing soil types, they are more inclined to take soil samples from 2.5 acre grids. They also grid sample new farms their clients acquire; farms that might not have been as well taken care of as the land they have farmed for years.

"One of the things our clients like most about the field maps is being able to keep field notes, where the weeds are, or where the low spots are," Dosch says. "They can make the notes right then and there, while they are in the field, right on the computer. They don't have to wait until they are back in the office on a rainy day, trying to remember exactly what they saw several days before. This new technology can be a huge benefit for a lot of farmers.

"Each farmer has to figure out how they need to use the technology so they can get a return on their investment. Spend your money where it will give you the maximum return."

John Havlin has spent years working with emerging precision agriculture technology, attempting to quantify the benefits of the technology.

"We know intuitively that precision agriculture technology offers the greatest opportunity to improve crop productivity and input efficiency while protecting the environment," says the soil scientist and authority on precision agriculture. "Our work is designed to prove these benefits. U.S. agriculture has developed from hand power to horsepower to mechanical power and science power. Now we are entering the age of information power. Precision agriculture offers us the opportunity for integrated problem solving, producing optimum yields, problem solving and meeting environmental regulations."

Existing precision ag technology allows farmers to collect soil, pest and crop information, integrate and interpret that information and develop prescriptions for farming. Another approach uses on-the-go sensors to collect and interpret field data and make decisions such as what and where to spray chemicals or apply fertilizer, or increase or decrease seeding rates.

"One of the hottest areas of research is remote sensing ( with infrared photographs like those used by Hood)," Havlin says. "We can evaluate nutrients, pesticides, water and other parameters. We can evaluate phosphorus or nitrogen loss, riparian buffer effectiveness and make soil erosion assessments. We have examples where variable rate technology profitability can be substantiated for lime and phosphorus and in some cases nitrogen. Yield monitors are being adopted extensively. Management zones within fields are becoming more practical.

"I believe precision technologies are here to stay," Havlin says.

Farmers attending the 2000 Southeast Vegetable and Fruit EXPO and AgTech 2000 had an opportunity to hear from dozens of farmers and other experts in precision agriculture, vegetable and fruit production, harvesting and marketing and numerous other valuable topics.