Fertility Influence of the U.S. Midwestern Soils on Yellow Shoulder Disorder in Processing Tomatoes

The economics of processing tomato production are driven by soluble solids content, viscosity, color, and color uniformity of the fruit. Ripening disorders that affect color are a major limitation to the economic success of processing whole-peel and diced products. The causes of ripening disorders are not completely understood, although it is clear that soil nutritional status, weather, plant genetics, and interactions among these variables are important factors. We sampled both soil and fruit from fields in Michigan, Ohio, and Indiana and were able to correlate soil fertility properties and fruit color. The correlation between soil properties and fruit color was different for fine- and coarse-textured soils. Fine-textured soils presented more frequent, but weaker, correlations with absolute color and within-fruit color differences when compared with coarse-textured soils. For fine-textured soils, exchangeable K correlated with a measure of within-fruit variation, L* difference (L*(diff); r = -0.21, P < 0.01). Other measurements of K nutrition, K center dot Mg-1/2 ratio, K-act, and K-%CEC, all correlated to the same extent (r = -0.29, P < 0.01). The highest correlations were identified between soil-available P and L* (r = -0.33, P < 0.01) and L*diff (r = -0.31, P < 0.01). In coarse-textured soils, exchangeable K correlated with L* (r = -0.373, P < 0.05), b* (r = -0.49, P < 0.01) and Hue' (r = -0.37, P < 0.05). K center dot Mg-1/2 ratio and K., yielded higher correlation coefficients with absolute color measurements when compared with fine-textured soils. Soil-available P was correlated with L* (r = -0.375, P < 0.05), a* (r = 0.49, P < 0.01), Hue degrees (r = -0.46, P < 0.01), and C* (r = 0.401 P < 0.01). For coarse soils, K-Mg-1/2 ratio, K-act, and available P were important properties when the color of tomato fruit is of value. In all cases, higher exchangeable K and P nutrient status had a positive correlation with fruit color. Our sampling could not detect interactions among weather, genetics, and soil, and further work will be necessary to clearly describe the role of interactions in determining fruit quality in tomatoes.