Discourse Journal of Agriculture and Food Sciences
Volume 4 Issue 1 Page 1 - 10. June 2016

Copyright 2016 Discourse Journals

Evaluation of Testing Kits for Routine Soil Analyses

Brandenberger, L. P.1*, Bowser, T. J.2, Zhang, H.3, Carrier, L. K.1 and Payton, M. E.4

1Department of Horticulture and Landscape Architecture,
2Biosystems and Agricultural Engineering,
3Plant and Soil Sciences,
4Statistics, Oklahoma State University, Stillwater, OK 74078


Soil test results from commercial and university laboratories are normally accurate, affordable, and typically come with recommendations for fertilizing specific crops. Soil testing by these labs is easily accessed in developed countries making it difficult to replace with anything else. Three soil test kits were evaluated on 20 diverse soil samples to determine their potential as a replacement for standard laboratory tests. Of the three test kits included in the study (LaMotte, Luster Leaf, and Rapitest), all were capable of testing pH, nitrogen (N), phosphorus (P), and potassium (K). Results indicated that there were differences between the kits regarding their ability to accurately and reliably measure soil pH and plant available N, P, and K. The kit that demonstrated the most potential for these tests was the LaMotte soil test kit. It most closely correlated with test results of Oklahoma State University Soil, Water, and Forage Analytical Laboratory (SWFAL) for soil pH and P and correlated to a lesser extent for N. All test kits, however, were poor predictors of soil K levels when compared to the results using standard laboratory procedures. Those considering using soil test kits in lieu of soil testing laboratories should take into consideration that not all soil testing kits are accurate or reliable. Furthermore, results from standard laboratories will provide farmers and gardeners with reliable results and recommendations. When the option of using a soil testing laboratory is not available soil test kits can provide a substitute for standardized tests, but with much less accuracy and the results may misguide lime and fertilizer applications resulting in over or under fertilization and potential negative environmental effects.

Keywords: Soil testing, soil-testing kits, nitrogen, phosphorus, potassium, pH.

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