Vincent de Leijster

78 Chapter 4 increases from around €5 kg -1 to €6.5 kg -1 (Lonja de Reus, 2019), which are increases of 92% in subsidy and 30% in price. Although strong financial benefits are currently provided, this management still results in strong negative effects on ecosystem services provisioning as long as it is combined with conventional tillage (De Leijster et al., 2019). Therefore, we suggest that organic certification schemes should incorporate criteria on organic amendments and farm floor management, to further mitigate environmental degradation. 4.4.3 Payments for environmental services Payment for carbon sequestration is often claimed to be an important incentive for farmers to apply soil rehabilitation practices (Lal et al., 2015). In the current study we found that carbon markets —under the current conditions— cannot provide compensation for the opportunity costs in almond plantations. The average voluntary carbon price was too low to make a noticeable difference in almond farmers’ annual budgets (0.02-0.04% of total income) and also the fourfold EU-ETS carbon price was still too low to compensate for the opportunity costs (1.06-1.40% of total income). Antle and Stoorvogel (2009) described three case studies of payments for agricultural soil carbon sequestration in developing countries and also concluded that in each of these cases the additional payment was only partly compensating for the opportunity or implementation costs of the carbon mitigating practices applied by farmers. The authors concluded that, for their case studies, the carbon price was too low, and that prices of up to $200-300 tC -1 should be paid to fully compensate for the restoration practices. Moreover, the payment for carbon sequestration schemes, where farmers are paid per ton carbon sequestered in the soil, are less effective in the Mediterranean region, as soil organic carbon content of Mediterranean soils changes relatively slowly and remains low compared to other biomes (Montanaro et al., 2012). We also showed that erosion generated by CT managed almond plantations had an estimated cost of €121.35 ha -1 y -1 . These costs can be reduced significantly by the vegetation covers of NT and GM, as they reduced erosion by 71.4 and 73.1%, respectively (Appendix Table A4-5). Even though erosion was significantly reduced by NT and GM, soil erosion was not fully prevented and still led to additional cost. Due to the low income of NT, this management regime experienced the largest reduction in NPV. Internalizing the costs of erosion in the farm’s budget does not result in an improvement of the profitability of agroecological practices in this setting. The erosion costs in our study were higher than those reported in another study on Spanish almond plantations, where the authors estimated an average erosion cost of €27.16 ha -1 y -1 (Hein, 2007). However, Hein (2007) emphasized the on-site costs of nutrient loss and did not consider the loss and replacement of soil and SOM,