Vincent de Leijster

11 General introduction 1 For example, reduced tillage improves soil microbial biodiversity, erosion control, and water regulation, but in some cases it may negatively affect nutrient availability (Rosa-Schleich et al., 2019). Nevertheless, the total ecological performance is often found to be higher in agroecological systems than in conventional systems (Kearney et al., 2017; Schulte et al., 2017; Torralba et al., 2016). This suggests that agroecology is the ‘promised land’ in terms of ecological impact, but also raises the question whether it is already viable from a business perspective. There have been fewer studies on the economic impacts of agroecological practices than on their ecological impacts. Most often, the yield of the main crop is measured to provide an indication of economic performance. Some researchers expect that the intensification of ecological processes will improve agroecosystem productivity and thus result in higher yields (Kleijn et al., 2019a). However, the effects of agroecological practices on yields have so far been found to be variable. For example, vegetation cover in Mediterranean orchards has a positive effect on erosion mitigation, water retention, and biodiversity, but negatively affects the yields of almonds, olives, and grapes (De Giorgio & Lamascese, 2005; Gómez et al., 2011; Maetens et al., 2012b; Martínez-Mena et al., 2013; Rodrigues et al., 2018). In a global analysis, researchers found that in general, cover crops and reduced tillage negatively affect yield of the main crop, while the effect of agroforestry on the yield of the main crop varies between cropping systems and regions (Rosa-Schleich et al., 2019). Still, vegetation diversification in agroecosystems has been found to attract more pollinators, resulting in higher fruit-set ratios, which theoretically may improve the formation of fruit and therefore the yield (Klein et al., 2003a, 2012). Yields of the main crop are, however, not the decisive factor for economic performance. The price of the crop – which is often related to its quality – the production of other products on the farm, and the management costs also contribute to economic performance. In the global analysis by Rosa-Schleich et al. (2019), the agroecological practices, cover crops and reduced tillage were found to be more profitable than conventional management since they led to cost saving. Agroecological practices may also influence the quality of the products; for example, it was demonstrated that vineyards with ground cover produced grapes with higher levels of aroma compounds and sugars, which potentially results in better wine (Xi et al., 2011). Moreover, some studies showed that agroforestry management improves the quality of coffee beans as the shade provides a more stable temperature and humidity, which in turn lead to a more uniform ripening of the berries (Jaramillo et al., 2011; Muschler, 2001; Vaast et al., 2006a). Higher product quality may result in a higher price, which contributes to better farm profitability. Adjusting the economic value of products is one economic intervention that may alter the profitability outcome. Section 1.3 provides a more detailed discussion of this and other economic interventions.