ST/MZ is our soil testing process that provides growers with nutrient information about their soils. Our samples are taken by Soil Type and Management Zone (ST/MZ) rather than by grid, because we understand that variations in soil type are not conveniently bound within congruent squares. Drawing soil samples from logical, scientifically selected regions allows our Ag Spectrum representatives to make valuable recommendations on phosphorous and potassium rates, herbicide selection, hybrid placement, seeding rates, nitrogen timing, gypsum applications and liming needs. Soil samples are pulled using special supplies and a Geographic Information System (GIS) file. Midwest Laboratories provides consistent and accurate results of each soil sample. Rapid turnaround ensures that valuable data is on hand when you need it to make critical decisions about plant nutrition, and we recommend repeating soil tests every two to three years for maximum results.


Once results are confirmed, our Ag Spectrum Associate will meet with the grower and provide a professionally prepared report that is easy to read. This report includes:

  • Soil sample lab results
  • Full-color ST/MZ maps, depicting zone boundaries and soil types, with percentage of each soil type
  • 7 nutrient maps showing levels of organic matter, pH, CEC, potassium (K), calcium (Ca), phosphorous (P), and magnesium (Mg)
  • Lime, P, and K recommendations with estimated cost breakdowns
  • USB flash drive containing electronic copies and digital prescriptions for lime, P and K, as well as viewable files for all maps


Ag Spectrum makes data interpretation easy. Soil test data is instantly integrated into our Maximum Farming Recommendations. These recommendations include Ag Spectrum products, along with other fertility and soil amendments, that work together to allow Ag Spectrum associates to help farmers improve their production. The modeling used in the system is based on an understanding of optimum requirements for the grower’s crop. The recommendations don’t just “treat the crop” – they treat the soil – bringing it to optimum levels to enable life in the soil and crops to thrive. 


Next topic:  In-Season Nutrition


Today’s farmers need the most accurate information they can get to make good decisions about inputs.  One of the most important sources of information for a farmer is a complete, current understanding of the soil.

Soil testing is simply a snapshot that represents the current state at the time of testing. As we grow crops, nutrient availability decreases. Conditions will fluctuate naturally based on microbial activity, weather, and production management decisions. As a result, soil tests by themselves do not give farmers a complete picture – other factors and dynamics have to be considered. However, regular testing, and good interpretation of results is a critical piece of the puzzle.

Therefore, soil testing is an important starting point. Results from testing soils tell you what nutrients exist, how favorable the root environment is, and what can be done to alter the root environment to a farmer’s advantage. 

At Ag Spectrum, we create “management zones” for each new customer and each field. We start by identifying soil types on a base map obtained from the U.S. Geological Survey. Using this map and production data, we identify specific “management zones.”

We combine zones of less than two acres, to reduce frustration since it is unlikely the customer will want to manage anything less than that separately. Several samples are collected within each area and are combined into one bag for testing.

By identifying large areas with similar characteristics, there is less need to pull many samples from large areas, which in turn provides better information at less cost.  Farmers using a grid would have to obtain samples every half-acre to match the accuracy of the ST/MZ map shown here. The fields should be sampled every 2-3 years as soil changes over time. 

This approach to sampling by Soil Type and Management Zone, abbreviated as ST/MZ, provides an in-depth analysis to help optimize your crop production.

 Soil Samples by Zone

Soil samples taken by soil type and management zone enable a “prescriptive approach” for each field.  In the Maximum Farming System, soil testing is an important starting point. Results from testing soils provide information about nutrient availability, how favorable the root environment is, and what can be done to alter the root environment to a farmer’s advantage. 

 Maximum Farming Recommendations

Growers are provided specific recommendations for their crop that are developed with our proprietary recommendation software to enable a farmer to implement the Maximum Farming System

Maximum Farming Reports 

The Maximum Farming Report is the tool used to evaluate choices and help the farmer plan for next year’s production decisions. Layers of GPS data from individual fields enhance the Maximum Farming Report. It is a powerful tool that can help track production trends in various conditions.

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