Model STH Series – Combination Soil Testing Outfits

determination of available nutrients found in agricultural soils

This line of combination soil analysis outfits offers the finest visual color matching system available to today’s agronomist. Technically advanced reagent systems and unique extraction procedures based on the Mehlich I extraction provide fast, simple and extremely accurate soil testing.

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The Model STH Combination Soil Outfits have offered simplified methods for determination of available nutrients found in agricultural soils for over forty years.

Since the original introduction of the STH series, based on Morgan soil test methods, reagent systems have been updated constantly with new advancements in modern chemistry. A series of rapid, accurate chemical tests use standardized reagents to produce color reactions measured against laminated color charts.

All STH outfits are furnished in lightweight carrying cases with components securely mounted in removable foam trays. This format provides flexibility for the in-house specialist who also wants to make quick problem determinations in the field.

Colorimetric test methods are used for most test factors. Tests for calcium, sulfate and chlorides are based on turbidity measurements. Potassium analysis also employs a turbidity measurement, using a unique reading device designed in LaMotte laboratories to read directly in pounds per acre. A single extraction procedure, using Morgan Universal Extraction Solution, provides the liquid soil extract for all the nutrient tests with the exception of chloride, which is extracted with demineralized water. The Humus Screening Test, performed on a soil sample-demineralized water suspension, employs five color standards for rapid measurement of humus content of the soil.

Soil pH is determined colorimetrically, using a series of pH indicators and color charts covering the range of pH 3.8 to 9.6. The STH outfits also include simplified procedures for screening nitrates, phosphorus, and potassium in plant tissues. Complete reagent refill packages are available for each STH outfit.

Each kit includes complete instructions, a soil management handbook and a pad of soil analysis report forms. The LaMotte Soil Handbook contains general information on interpretation of test results for determination of lime and fertilizer requirements.


Ordering information 

Model STH-4 Code 5029 pH, Nitrate Nitrogen, Phosphorus, Potassium 

Model STH-5 Code 5007 pH, Nitrate Nitrogen, Phosphorus, Potassium, Hummus (organic matter)

Model STH-7 Code 5061 pH, Nitrate Nitrogen, Phosphorus, Potassium, Hummus (organic matter), Calcium, Magnesium 

Model STH-14 Code 5010-01 pH, Nitrate Nitrogen, Phosphorus, Potassium, Hummus (organic matter), Calcium, Magnesium, Ammonia Nitrogen, Manganese, Aluminium, Nitrite Nitrogen, Sulfate, Chloride, Ferris Iron. 

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