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.

In this study, the authors aimed to evaluate the productivity, gross mixed income, and contribution of marketable ecosystem services and disservices in this apple-arable agroforestry system, relative to conventional arable systems that consist of a yearly rotation of crops in monoculture. They selected three ecosystem services / disservices based on the availability of empirical data and/or existing models, comprising (i) arable pest and weed pressure, which has been identified as a potential cost of agroforestry by UK arable farmers (Graves et al., 2017); (ii) pollination, which is important for the quality and quantity of apples produced, for example in the absence of pollination, apple yield is reduced by around 55 to 60% (Garratt et al., 2014; Webber et al., 2020); (iii) carbon sequestration and reduced emissions. They combined primary data collection with a series of ecosystem service and cost-benefit analysis models to explore the following research questions:

1. Does arable crop yield differ between the agroforestry system and arable controls, and is this associated with invertebrate pest abundance and weed cover?
2. How does apple yield in the agroforestry system compare with typical orchard yields, and does apple pollination differ between agroforestry and orchard systems?
3. What is the value of carbon sequestration and reduced emissions in the agroforestry system compared with the arable controls?
4. Theoretically, how does gross mixed income of the agroforestry system compare with arable controls, how does empirical case-study data compare to these theoretical expectations (cost-effectiveness analyses), and which factors most strongly influence gross mixed income (sensitivity analysis)?