Vincent de Leijster

70 Chapter 4 the study reports average off-site social costs of €111.52 ha -1 y -1 (based on 85.92 ha -1 y -1 in 2003 with inflation correction), which include siltation of dams and canals and costs of sedimentation. Combined, these costs add up to €121.35 ha -1 y -1 for CT. In the appendix Table A4-5 we show the results of a literature review that demonstrates that NT and GM reduce erosion by 71.4% and 73.1%, respectively. Therefore, we attributed erosion costs of €34.71 to NT and €32.64 to GM. For all analyses the discount rate was kept constant at 5%. 4.3 RESULTS 4.3.1 Costs and benefits In the field experiment we found differences in almond yield between treatments (Appendix Figure A4-1&2). We found that CM produced the highest yields with an average of 1.47 kg per tree, followed by an average almond yield (kg tree -1 ) of 1.12 for CT, 0.77 for GM and 0.67 NT, which resulted in the relative production values of 1 for CT, 0.6 for NT, 0.63 for GM and 1.20 for CM. Consequently, the gross revenue generated from almond production followed the same order (Figure 4-1), with —compared to CT— 13.0% higher gross revenue from CM and 35.3% and 20.5% lower gross revenue from NT and GM. In 2017 the lowest production was measured in our site, due to a combination of exceptionally cold temperatures in Spring causing frost and the alternate bearing behavior of almond trees (SM. Figure. S1). Table 4-2 and Figure 4-1 show farm-level costs, benefits and net revenues per hectare. The response rates (n) per cost category were low, with an average of 5.1 out of 15 respondents for the operational costs. Farmers rarely recorded costs in financial reports and therefore we only included those that farmers did record in notebooks, where they kept notes of those they paid recently, or where they were sure of for another reason. None of the interviewed farmers documented the administrative and capital costs of the farm, such as insurances, social security, taxes, land costs and deprivation costs, and therefore these costs were taken from the literature (Table 4-2). NT had 20.5% lower operational costs than CT, as no tillage resulted in lower operational, labor and diesel costs (Figure 4-1). The operational costs of GMwere comparable with CT (3.8% lower), and the operational costs of CM were 15.3% higher than CT because of additional costs for compost application. In an average operational year, CM generated the highest net revenue of €1,349 ha -1 y -1 , followed by CT, then GM and then NT, with €1,126, €636, €415 ha -1 y -1 , respectively (Figure. 1). The opportunity costs per operational year were €711 ha -1 y -1 for NT and €490 ha -1 y -1 for GM.