Organic farming may affect the nutritional value of vegetables

The demand for organic products is constantly increasing in parallel with people's concerns for environmental and health issues. In general, the nutritional value of organic products is not different from conventional crops; however, scattered evidence for the accumulation of valuable metabolites in organic products exists. Here we analysed the variation of nutritional metabolites in three vegetable crops cultivated under organic or conventional farming, and we attempted to establish a functional link between physiological responses and cultivation regime. Cauliflower, endive and zucchini were grown in two types of soil (clay or sandy) under two farming systems (conventional or organic), in three independent experiments. For each experiment, additional variables were tested, namely cultivar (cauliflower), nitrogen level and mulching (endive and zucchini). Our results indicate that cultivar-specific genetic determinants and cultivation factors, including the farming system, may strongly interact to affect important quality parameters of vegetables. Based on these results, we conclude that it is possible to improve quality standards in organic farming by using functional combinations of agronomic factors. This is critical to fully exploit the potential of organic horticulture.