Description
Achieve immediate and economical soil analyses in the field without sacrificing accuracy. This self-contained, electronic soil analysis laboratory provides accurate answers for 15 different soil factors, including available forms of macronutrients and critical micronutrients. The digital SMART®3 Colorimeter instantly analyzes color reactions developed in nutrient tests. Display readings are multiplied by a conversion factor specific to each test to provide a result in parts per million (ppm) or pounds per acre (lb/acre)—no further calculations are necessary. Simplified colorimeter test procedures provide at least 20 tests for nitrate/nitrogen and nitrite/nitrogen; 50 tests for ammonia nitrogen, phosphorus, sulfur, iron, manganese, and zinc; and 100 tests for potassium and copper. An additional 50 tests using direct reading titrator tests are provided for calcium, magnesium, and chloride. All tests are performed in minutes on easy-to-prepare soil extracts.
Unit Conversion Factors
Results can be measured using a choice of units, explained here. Parts per million (ppm), pounds/acre, and kilograms/hectare units can be converted to each other using these values:
| Area | Soil Depth | Soil Weight |
| 1 acre | 6-7″ | 2 million lb |
| 1 hectare | 15-18 cm | 2.25 million kg |
| ppm | lb/acre | kg/hectare |
| 0.5 | 1 | 1.12 |
| 1 | 2 | 2.24 |
| 0.89 | 1.78 | 1 |
In addition to the values obtained, a number of variables must be considered when interpreting soil test results. These variables include the composition of the soil, drainage, climate, previous fertilizer programs, and the type of plant to be grown. Samples must truly represent the area being studied and must be carefully selected.