Productivity, biodiversity trade-offs, and farm income in an agroforestry versus an arable system

The uptake of diversified farming systems is constrained by a scarcity of evidence regarding financial costs, benefits, and risks. Here, we evaluate the productivity and projected farm income of an agroforestry system, where apples are integrated with arable crops, by combining primary data with ecosystem service and cost-benefit models. Our ecosystem service assessments included: 1) weed and pest associations with arable yields; 2) apple seed set as a proxy for pollination, and; 3) carbon sequestration. Arable yields were up to 11% lower in agroforestry than arable systems, and were significantly negatively associated with weed cover in both systems. Apple yields in agroforestry were similar to typical yields from comparable orchards. Apple seed set was significantly higher in agroforestry than conventional orchards for one of two varieties. Predicted gross mixed income was higher in agroforestry than arable systems in 15 of 18 productivity scenarios over 20 years, which was supported by a case-study. Apple yield and price were the major determinants of gross mixed income. Payments for carbon sequestration were predicted to contribute 47% to 88% of agroforestry establishment costs. This study demonstrates how a diversified farming system can improve farm income, but grant support would reduce the initial negative cash-flow.