72-5 Comparison of Portable Soil Test Kits for Smallholder Farmers.
Based on the recognition that portable soil test kit would facilitate smallholder farmers to have an onsite capability for soil analyses the following soil test kits were evaluated against standard laboratory tests: Hach, SoilDoc, and Kasetsart University (KU) soil test kits. Other innovative techniques being evaluated include chromatographic and spectral analyses. The results showed the different capabilities from each test kits. For instance, Kasetsart was the cheapest with very limited capability but with the ability to analyze for ammonia-N besides nitrate-N, P, K, and pH. Hach and SoilDoc were a lot more expensive with more capabilities. Hach has the ability to analyze for N, P, K, Ca, Mg, Na, acidity, salinity, gypsum and lime requirement. SoilDoc’s major quality is the feedback and recommendations done through a digital media (tablet). It can analyze nitrate-N, Ca, Mg, P, K, acidity, sulfate, EC, and active carbon. The comparison of results from these soil test kits and wet-chemistry method is presented for a wide range of soils. Modifications to improve the kits are also discussed.