Background and methodology:
Tomatoes grown for processing are a major vegetable crop in California that typically relies on inputs of mineral fertilizers and other agrichemicals, irrigation, and relatively intensive tillage. This study evaluated the influence of 10 years of organic, low input, and conventional management practices on processing tomato yields, fruit mineral composition, and soil chemical properties in the Sacramento Valley of California.
This research did not reveal any significant differences in yield between tomatoes grown using organic management practices and those grown using conventional farming practices. The organic system produced fruit with a higher phosphorous concentration than conventional and low input systems. Tomatoes from the low-input system had a 17 percent lower calcium concentration compared to organic tomatoes. The nitrogen concentration in the conventionally grown tomatoes was 38 percent higher than the organic tomatoes, probably due to the nitrogen fertilizer (side-dressed during cultivation) used in the conventional system. A low concentration of nitrogen in organic fruit could be a positive attribute for processing. The use of organic farming practices in California’s Sacramento Valley over a 10-year period resulted in higher soil carbon, nitrogen, soluble phosphorous, ex-changeable calcium, and potassium than conventional and low input systems.
Colla, G., Mitchell, J. P., Poudel, D. D., and Temple, S, R. (2002). Changes of tomato yield and fruit elemental composition in conventional, low input, and organic systems. Journal of Sustainable Agriculture 20(2): 53-67. Available on-line at:http://dx.doi.org/10.1300/J064v20n02_07