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Solum’s Field Moist Approach

Field moist testing provides better predictions for potassium needs

Potassium (K) is an essential nutrient for crop health – without sufficient levels, growth is stunted and yields are reduced. Current measurement methods involve drying and grinding the soil, which can affect the chemistry and alter the amount of extractable K. Inaccurate K measurements mean that retailers and producers need to guess on what is right.   Solum’s field moist processes mix soils with water instead of drying them to a fine powder, resulting in more accurate and repeatable K measurement that provides better predictions for potassium needs.

See the Difference

Traditional lab processes can change the bio-available numbers reported by labs. Potassium is often bound with the layers of clay minerals. Drying soils can expand this interlayer area and release or trap potassium that the plant cannot see. Our Field Moist process measures the soil as the plant sees it, resulting in more representative data.


Traditional Soil Testing Results k_colormap01b
Solum’s Field Moist Soil Testing Results k_colormap02b
Fields measured with both the traditional dried and ground and
field moist process can show radically different results, resulting in very
different fertilizer recommendations.

This is the biggest change I have seen in the soil measurement industry in 15 years. … I feel field moist preparation will solve a significant portion of the problems we have in managing potassium.”

— Paul Fixen – SVP of Americas and Oceania, IPNI


Better at Predicting Crop Potassium Needs

Recent studies have again shown that field moist measurements of soils are up to twice as good at predicting crop needs for potassium.

Soybean: Dry and Moist K Field Correlation
Field moist potassium measurements provide better predictions of
yield relative to controls where no fertilizer was applied.

Consistent Over Time

While the primary reason for taking soil samples is to predict crop response, soil testing is also an important tool for tracking changes over time.   The following graph shows results from a long term study at Iowa State were fertilizer was applied to a number of plots at a build rate (72 lb K2O/acre/year) a maintenance rate (36 lb K2O/acre/year), or not at all.   Soil test levels were measured with a field moist methodology for 14 years and the second 14 year period was tracked using the simpler dried and ground technology.  The result?   While both methods show significant variations from year to year, the field moist process was much more capable at tracking increasing and decreasing fertility levels while the dried and ground method was not able to track any meaningful tends at all.     Soil testing is still the best way to manage fertility needs, but the data shows it pays to do the tests right.




Need more help on how to use these results?

Iowa State now has guidelines for how to use field moist results. Solum has conducted trials in 15 U.S. states and on three continents that show the effect exists across the entire corn belt and in other countries as well.

About Solum™

Solum’s™ mission is to develop software and measurement technology that makes the business of Agriculture simpler and more productive. Our advanced soil nutrient and fertilizer response models are developed by Solum's™ industry leading soil measurement laboratory in Ames, Iowa.

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Ames, IA 50010
(515) 661-5500

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