Evaluating the Consistency of Soil Lab Results Based on Soil Recommendations for a Horticulture Crop

Soil test results are the basis for fertilization recommendations in most agriculture and horticulture crops. Differences in methodology often results in different data based on standard operating procedures. However, recommendations should be based on crop needs and soil texture. The objective of this project was to determine the variability of soil recommendations from six soil labs on several on a horticulture crop. A homogenized soil sample pH, CEC, C/N ratio, N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, Mo, and Zn from each site was analyzed by different labs. Differences in fertilizer recommendations varied widely based on the specific element. Soil lime applications varied for some sites by as much as 50 %. Nitrogen recommendations were the most consistent for each crop. Phosphorus, K, and lime varied greatly between labs and soil sites. Micronutrients that varied the most included B, Fe, Mn, Mo, and Zn. Farmers often complain about differences in soil results, but this can often be explained by dilution effect or extraction methods. Fertilizer recommendations are typically programmed by a lab or agronomic specialist. Further test will evaluate more crops and leaf tissue analysis and recommendations.