The clattering farm tractors of yesteryear were uncomplicated machines equipped with That’s all you only a few accessories, all of which could be easily maintained and repaired by the farm families fortunate enough to own them. By contrast, today’s mechanical descendants, rumbling across Nebraska’s sugar beet fields, are often bristling with cabmounted Navstar receivers, digital […]
The clattering farm tractors of yesteryear were uncomplicated machines equipped with That’s all you only a few accessories, all of which could be easily maintained and repaired by the farm families fortunate enough to own them. By contrast, today’s mechanical descendants, rumbling across Nebraska’s sugar beet fields, are often bristling with cabmounted Navstar receivers, digital computers, full-color video displays, and electronic database memories programmed with custom-tailored Geographic Information Systems.
The sugar beet is a delicate plant requiring protection during the early phases of its lifecycle. Consequently, fast-growing cover crops – oats, barely, rye – are commonly seeded throughout the same field just prior to the planting of the sugar beet seeds. Then, when the sugar beets are being planted, a narrow stream of plant-selective herbicide is laid down with the beet seeds to destroy nearby weeds while allowing the protective cover crop to grow between the rows.
The local soil type and its organic content are of crucial importance in determining the optimum quantities of herbicide to apply. Too much herbicide damages the delicate sugar beets, too little allows weeds to grow and choke them within their rows.
Three different soil types are commonly found in close proximity in western Nebraska:
- Loam
- Sandy clay loam
- Coarse-textured sandy soil
When all three soil types share the same sugar beet field, the optimum amount of herbicide for effective results often varies as much as 50 percent.
Many of Nebraska’s sugar beet fields employ center-pivot irrigation systems in which an elevated self-propelled irrigation fixture pivots around a gigantic circle spraying water as it moves forward. Some center-pivot units irrigate flat, circular fields a half-mile or more in a diameter with practically no supporting labor.
Historically, the tractors planting sugar beet seeds have simultaneously applied uniform amounts of herbicide to destroy any weeds beginning to grown along the narrow beet seed rows. This compromise approach toward herbicide application is simple and easy to implement, but because soil types vary so much within a typical circular field, it does not achieve optimum results.
Fortunately, a Navstar receiver mounted in the cab of a tractor coupled with an onboard GIS database can help the operator optimize the application of herbicides in various portions of the field. Aerial photographs are used to pinpoint soil-type variations. These images are then digitized to form contour maps which are, in turn, fed into an onboard GIS database.
Differential navigation signals broadcast by local FM radio stations are used to fix the current position of the tractor to an accuracy of 3 to 5 feet. Farming industry surveys indicate that about 5 percent of America’s large-scale factory farms now use GIS technology to achieve substantial improvements in the application of liquid fertilizers and herbicides.
“Each area of the field receives only those specific nutrients that are recommended to produce the desired crop,” explains John Mann, president of Soil Teq, Inc., of Minnetonka, Minnesota. Everyone benefits from the high-tech approach. Costs are lower, productivity is higher, and pollution levels in local streams resulting from fertilizer-infused runoff quickly decline.
