If matching soil samples are sent in the same container, make sure they do not contaminate the plant tissue. For predictive samples, recommendations are computer generated. For diagnostic samples, agronomists review the lab results and provide specific recommendations. Results include concentrations of essential plant nutrients and potentially harmful elements on a dry weight basis. The nitrate nitrogen concentration of petioles is reported on a dry weight basis for crops requiring this precise prediction of nitrogen status.
Interpretation is based on sufficiency ranges established for each crop.
The index scale is divided into interpretation zones. Interpretation indexes vs. growth or yield. Luxury consumption may not be detrimental to yield, but it can influence quality and production efficiency. Nutrient concentrations below the critical value or above the mild toxicity point indicate that yield or growth may be reduced by 5 to 10 percent. Excess accumulation of some elements may decrease efficiency and point to environmental impact even though levels are not toxic to plants.