Background and methodology:
Five tomato cultivars were selected for this study: 4 with large fruit (Rumba, Juhas, Kmicic, Gigant) and one cherry cultivar (Koralik). The plants were cultivated in light loamy, sandy soil on certified organic and conventional farms in the Mazovia area of Poland.
In the organic system, all recommended standards for fertilization, plant protection, and rotation were applied. Fertilizers included horse manure and compost and plant protection included the biological insecticide Biobit 3.2 WP, the biofungicide Biosept 33 SL and the pesticide Miedzian 50 WP, all of which are permitted for organic farming. The organic crop rotation included legume plants and white mustard.
In the conventional cultivation, the mineral fertilizers were ammonium phosphate, ammonium nitrate, potassium sulphate, and lime. Fungicides included Bravo 500 SC and Amistar 250 S.C. Samples of fully ripe tomatoes were harvested in the same week of fruiting for chemical analysis.
Organic tomatoes contained twice the amount of total sugars compared to conventional tomatoes. In particular, organic cherry tomatoes had more total sugars than any of the other cultivars examined. The organic tomatoes also had higher levels of reducing sugars, whereas conventional tomatoes were higher in total acidity but the difference was very small. Cherry tomatoes also had higher total acidity compared to other cultivars and contained more vitamin C. Tomatoes under organic cultivation contained a statistically significant higher level of betacarotene compared to those grown under conventional management and more flavonoids.
Hallmann, E., & Rembialkowska, E. (2007). Comparison of the nutritive quality of tomato fruits from organic and conventional production in Poland. Poster presented at 3rd QLIF Congress: Improving Sustainability in Organic and Low Input Food Production Systems, University of Hohenheim, Germany, March 20-23, 2007. Available on-line at: http://orgprints.org/9944/