Should I Start With Yield Maps Or Soil Tests?
It depends on your area of the country. In some parts, soil testing on grids has been popular for years. In which case, it’s a natural to add GPS to that process to refine the information. In other areas, soil fertility is not the first limiting variable on yield. In these areas, farmers may decide that a yield map which identifies low-yielding areas, offers the quickest way to pinpoint ways to boost yield.
“You can map the soil, but without the yield map, you don’t know what you have,” says Bill Reinert, Precision Farming Enterprises, Davis, Calif.
And for results-oriented operators, a yield map is a very tangible tool.
“Generally the best place to start is with yield monitors because they give a report card of what the grower is currently doing,” says Richard Johnson, Northwest Precision Ag, Blackfoot, Idaho.
Whether you start with GPS soil test maps, or with a yield map, you will be taking soil samples, GPS or not. Remember that the samples are only as good as the dirt that’s collected.
“Start with a good soil sampling program, using a good, consistent technique. If the sample is taken poorly, it will result in inaccurate information,” say Brian Dirkson, Precision Farming L.C., Dows, Iowa. “It’s a shame to spend up to $15 per acre for a GPS-based soil test and variable-rate-fertilizer application and have it all based on inaccurate samples that don’t reflect reality.”
In most cases, experts agree that combining the yield monitor results with fertility maps gives an excellent cross-reference of your crop performance, So, if you can afford it, do both.
What To Buy First?
Most everybody agrees: Get a yield monitor first. The yield monitor represents a very “robust source of data” about your field as one precision agriculture guru puts it.
One suggestion from our experts is to select a yield monitor that allows you to make field observations and flag the information to a GPS location during harvest, allowing you to note weed patches, wet spots, thin stands and other trouble areas from the combine cab. Many farmers already make observations on a note pad or other device during harvest. This allows you to add a GPS location to the information so it can be plugged into your precision farming database and cross-reference the information to yield, fertility and/or soil type information later. Versatility of the GPS system is another factor to consider.
One of the hidden issues with a factory-installed yield monitor is the versatility of the GPS receiver. Some of our experts suggest that you use the GPS receiver in connection with a laptop for in-field observations throughout the year. If you can’t get the receiver off the combine, or if it doesn’t easily link to your four-wheeler, you may have a bit of a problem.
“You ought to be able to take the GPS out and put it on a four-wheeler,” says Tracy Meiners, Agrem Inc., Anchor, ILL.
What’s The Best Overall Advice?
As is often the case with major changes in your farming business, it’s smart to start with the end in mind. If you can determine the role that precision farming information will have in your operation, it makes many of the other decisions about product and serice providers mch easier. In some cases, you might be able to get by with surprisingly little new equipment.
The software that comes with your yield monitor is plenty for the first year. For 35% of the people, that’s all they will ever want. Another 15 to 25% will never own a computer and will have somebody else do maps,” says Meiners.
It’s nice to have a local resource that clearly understands your vision for the role of precision farming technology in your business. They will be a better adviser and cause you fewer headaches if you are clear right up front what you need from them. And insist on getting personalized service instead of a cookie-cutter approach.
“Look for situation-specific advice when you talk to precision agriculture suppliers,” say Stephanie Dickson, Geo-Ag Tech Ltd., Springfield, Ill.
And it’s wise not to expect too much as you start out on your precision farming journey. Remember that you are building a database of information that will identify trends and help you manage the future performance of your ground.
“Do not look at one round of soil tests as the entire answer. You will need several years worth of this data before you will start to find matching trends,” says Andy Hill, Premier Technologies Inc., Auburn, Ind.
As you embark on the process of building this database, remember that some of your decision at the beginning will lay the foundation for opportunities to come later, don’t be short-sighted.
“When you start with precision ag, don’t leave things out or take short cuts. You will regret it every time. As time goes by, you will find that the data and information will grow in value, even if there seems little use for it now, says Northwest Precision Ag’s Johnson.
When you look at your initial investment in precision farming tools, you might be wise to remember the old saying: “Never enought time to do it right, but always enough time to do it over.” In precision farming, it can be paraphrased as: Costs too much to do it right, but I won’t get a chance to do it over.”
Editor’s note: This article first appeared in the February 1998 issue of PrecisionAg Illustrated.