Soil Quality from Long-term Organic Management Nearly Doubles Flavonoids in Organic Tomatoes
For more than ten years, scientists at U.C. Davis in California have conducted a Long-Term Research on Agricultural Systems project (LTRAS). The impacts of conventional and organic management on tomato production and tomato nutrient concentrations have been a major focus of this effort.
On June 23, 2007, the American Chemical Society’s Journal of Food and Agricultural Chemistry published compelling results from the LTRAS (Mitchell et al., 2007). The team found that the level of quercitin, the most common flavonoid in the human diet and the major flavonoid in tomatoes, increased 79 percent as a result of organic management, and kaempferol levels rose 97 percent.
In addition, and significantly, the longer a field was managed organically, the bigger the margin in flavonoid levels between organic and conventional plots. The level of quercitin in the organic plots increased about 5 milligrams per gram of dried tomato per year, with the largest increases coming after seven years of organic management. In the conventional plots, quercitin levels increased only 2 mg/gram per year. This finding supports the need for a three-year transition period before a field is eligible to grow certified organic crops, and also helps explain the relatively smaller percentage increases in antioxidant levels typically found in university studies that entail just a few years of organic management.
Read full article here.