This paper analyses the effect of environmental and quality improvement practices on the value added of the fruit and vegetable sector. These practices form part of the incentive-based programmes established by the Common Agricultural Policy. Taking the investment in quality-environmental activities as knowledge capital, we propose a specific analysis that evaluates the effect of the factors of the production function and of the current subsidies over the value added. In general, the share of quality environmental activities in the rise of the product's market value is quite high. The analysis reflects that the expenditure on these activities is still higher than their benefit, and that the current subsidies can hardly be considered encouraging factors for the development of the above-mentioned practices.