If you're struggling to make sense of the site-specific data you've collected with satellite-based Global Positioning Systems (GPS), there's help.

A new service pulls together yield maps, soil samples, variable rate input application records, analysis software, weather forecasts, remote imagery and crop models under one electronic roof on the Internet.

In the past, many of those pieces had to be purchased from separate suppliers. "Everyone in the industry was hyping one leg of the elephant and not looking at the grower's interest in making a better crop," says Warren Hammerbeck, executive vice president of global product development for United Agri Products. "We've attempted to pull all this stuff together so we can run models that will give growers a degree of predictability on what is going on in their fields."

The overriding goal is to help you make better farm management decisions that lead to higher yields, lower input costs and a better quality crop.

The service, called mPower3, is independently operated by mPower3 Company, a subsidiary of United Agri Products.

Basic setup. The service is sold by subscription that can be renewed annually. Once you subscribe, an mPower3 technician will help you set up a virtual farm on the company's Web site through data and maps that show the boundaries of your field. To do that, you will need Internet access, and your computer should have Windows 95.

Within your field boundaries, you'll enter data that pertain to your farm, including hybrid and variety planted, yield, chemical and fertilizer applications, soil test results, tillage practices, irrigation schedules and scouting reports.

All this information is called your field management database. You can enter the data yourself or designate a company technician to do it for you.

"We can do it without stepping foot on your farm," says Scott Charbo, mPower3 president. Once your database is set up, you or your input supplier can automatically add new information such as the current year's soil sample results. The Web site software, called EmergeView, uses geo-positioning references to keep all the information in its relative place on your field. The software lets you view the information, create yield and fertility maps and generate reports that verify what was applied where.

At the end of the growing season, you'll get a CD-ROM of all your data for that year. You can label it, shelve it and draw on it at any time for reference.

Your data are also added to a general database, which you can query to make some generalized comparisons with how most growers are handling situations similar to yours. You own your farm's data, and it is confidential.

Factor in weather. As part of the service, 24-hr. weather information - including temperature, wind speed and precipitation - will be delivered to your screen each day.

The information is provided by WSI, a weather service that supplies many of the satellite images you see on TV. It uses radar stations, satellites and more than 1,100 weather stations across the United States to collect weather data that are accurate within a 2-km grid (approximately 900 acres). The data are then interpolated to the exact location of your field.

With the field-specific weather information, you will be able to fine-tune herbicide choices, rates and application timing, irrigation scheduling, hybrid maturities and planting dates for your fields. Predict crop stress. The weather data feed into crop models, also included in the service. A crop model is a computer simulation of crop behavior to be expected under current and predicted field conditions.

Crop models have been around for years. But to get them to work for a given farm, you need to put up a weather station for each field. For most farmers, that isn't practical. MPower3 makes crop models practical by giving you the weather information you'd get from your own weather stations.

Crop models use information about weather, fields and crops to help predict such variables as yield, pest and disease thresholds and optimum harvest dates. For example, at any point in the growing season, you can get an estimate on what your crop will yield in light of the latest weather in your area.

With that yield prediction, you can estimate expected return on investment from that field. This enables you to know the break-even point for each field's crop so you can determine, for example, whether it would pay to apply a late-season insecticide. And, as commodity prices fluctuate, you can use the same yield prediction to refine the marketing of your crop well ahead of harvest.

The models also evaluate the potential for pest damage and disease outbreaks that could damage your crop in a given field. Such pests include the European corn borer and diseases include Cercospora leafspot and potato late blight. If conditions are right for these problems, a red exclamation point will appear next to the field name on your Internet page. With the alert, you can better target your scouting activities.

You'll also get advisories for extreme weather conditions, such as temperatures below 32 degrees F or above 95 degrees F and wind speeds in excess of 40 mph.

Remote imagery. If you want even more information, you can purchase aerial images of your field, sent directly to your computer screen. The images are collected by a camera approximately 4,000 ft. away and can show details as small as 1 m.

Aerial images can be converted to stress maps with bands of color that help identify crops, their density and vigor, diseased areas, weed pressure and other problems, much like storm intensity color bands on TV weather maps.

Images may be taken at different stages throughout the growing season to reveal problems as they are happening. This allows you to take action in time to improve this year's crop. For example, you may need to till in a certain area or apply herbicides to another area.

Get answers. All of this information is stored in one spot on the Internet. You can download it to your computer at any time and analyze it with system software, also included in the package. Or, if you prefer, you can use your own analysis software. Analysis software lets you examine relationships between different variables to determine their effect on yield.

Crop specialists from mPower3 will be available to interpret the data and identify management strategies to increase yields or lower input costs. And because the service is independent, the specialists won't promote any one company's products or services, the company claims.

The service has been in the making for four years. In 1996 it was test marketed on 20,000 acres in Illinois. Last year, an additional 250,000 acres were enrolled.

Cost ranges from .50 to 1.00/acre/month plus a one-time setup fee of 1, 000. For less money you can buy an abbreviated package. Other services include soil testing, scouting, variable-rate applications, fertilizer blending, application records, custom layers and designs, irrigation analysis and custom data generation.

For more information, contact your nearest United Agri Products supplier or mPower3 Co., Dept. FIN, Box 1286, Greeley, CO 80632-1286, 970/346-6330 or visit the mPower3 Web site at http://www. mpower3.com.