Soil sampling and testing is one of the best tools we have to assess field nutrient availability. Yet in the small-grains growing area of the Northern Great Plains, only 10 to 15 percent of fields undergo annual soil testing, and only 25 percent are soil-tested every few years. The exceptions are areas of specialized crop production, like sugar beet or potato fields, where soil testing is mandated in grower contracts with processing companies. Because of increasing grain and fertilizer prices, demand grows for expanded soil testing to fine-tune fertilizer recommendations and assist in maximizing net returns.
Why are so many fields untested?Farmers usually don’t have time to do their own soil sampling, especially as the size of farms continues to increase. Further, some fertilizer retail locations have reduced their services because of insufficient staff. So in some cases, consulting agronomists take soil samples, get them analyzed by a soil test laboratory, and provide fertilizer recommendations. The challenge for these agronomists is that soil sampling is time consuming, limiting the number of fields they can realistically sample during the fall and spring seasons.
Who has the capability and capacity to do more soil testing?Hiring independent “third-party” soil sampling companies is a growing trend in soil sampling. These specialized businesses work separately from the fertilizer retailer and the consulting agronomist. Their clients consist of a mix of direct farm customers, retail fertilizer companies and even consulting agronomists. They are usually a one-person business operating within a limited geographic area such as a few adjacent counties or rural municipalities.
What is the advantage of using a third-party soil sampler?These samplers are specialists. They invest in good soil sampling equipment and associated location-fixing global positioning systems (GPS) to efficiently sample fields and take the required number of soil cores (15 to 20 cores per composite sample, for example) to achieve a statistically representative sample. Maintaining client trust and continued business requires them to provide high quality and accuracy in their sampling services.
How much does soil sampling cost?Fertilizer retailers used to offer soil sampling as a “free service” as long as the customer purchased the fertilizer from that specific retailer. In reality, the service was never free, but was paid through an increased margin between wholesale and retail prices. Today, most retailers charge for soil sampling and testing as separate services. The exact price varies from one area to another and depends on sampling methods. With rising fuel costs, third-party soil sampling will likely get more expensive. The charges are usually quite reasonable when you consider the time it takes, the cost of equipment, distances traveled and the value received by your operation— a good investment.
How many fields can a one-person soil sampling business sample in a year?Field time is the main limitation for soil sampling in the Northern Great Plains, with about two-thirds occurring in the fall after harvest and before freeze-up, and one-third in the spring before planting. In an average fall and spring period, samplers have about 40 suitable field days to take soil samples. In a 10- to 12-hour day, about 20 fields can be sampled, consisting of 15 cores per field for a total of 300 soil cores. But that’s if the fields fall within a relatively close proximity, for example, 20 miles (30 km).
Consider hiring the services of a third-party soil sampling business.Accurate soil test results can help you formulate adequate nutrition strategies while preventing excessive application rates of fertilizer to individual fields. This allows growers to maximize their net income and minimize the problems caused by over-applied nutrients.
Source: Dr. Thomas L. Jensen, Northern Great Plains Director, International Plant Nutrition Institute, 102-411 Downey Road, Saskatoon, SK S7N 4L8