Effect of Production System (Organic versus Conventional) on Olive Fruit and Oil Yields and Oil Quality Parameters in the Messara Valley, Crete, Greece; Results from a 3-Year Farm Survey

The demand for organic olive oil has increased rapidly over the last 40 years, but there is limited information on the effects of organic production methods on commercially and nutritionally relevant quality parameters in olive oil. The main objective of this farm survey-based study was therefore to compare fruit and oil yields and important oil quality parameters (including acidity, peroxide value and fatty acid profiles) between organic and conventional farms located in the Messara Plain and foothills. As expected, yields were substantially higher on farms in the Messara Plain compared with those in the foothills which have poorer soil, less access to irrigation water and are the more extensively managed. However, different to the many previous studies (which reported lower yields in organic systems), both fruit and oil yields were not significantly different in organic and conventional production and numerically similar to 10% higher in organic production. Additionally, olive oil quality was very high, and no substantial effects of production systems and farm location were found. Potential factors (e.g., low olive fly pressure) which may have contributed to the lack of a yield and quality gap between organic and convention production in the Messara region are discussed.