Guiding oil palm intensification through a spatial extrapolation domain framework

CONTEXT: Palm oil production has increased mostly via area expansion rather than yield increase. Increasing yields on existing plantation area, together with the proper regulatory and policy settings, can help meet future oil demand whilst reducing the requirement to convert natural ecosystems to agricultural production. OBJECTIVE: To develop a spatial framework delineating extrapolation domain (EDs) for oil palm that can be used to evaluate and extrapolate yield-enhancing technologies. METHODS: We developed the EDs based on climate, soil, and topographic factors that govern oil palm yields on mineral soils in Indonesia. We validated our framework using field-level yield data collected from 207 commercial blocks. We provided proof of concept by using the framework to identify areas suitable for yield intensification among independent smallholder farmers while possibly reducing encroachment on fragile ecosystems. RESULTS AND CONCLUSIONS: Our framework consists of a combination of climate, soil, and topographic factors. Most of the oil palm area was located within a relatively narrow range of biophysical conditions, with three EDs accounting for 74% of oil palm area. Validation of the spatial framework showed that EDs portrayed well spatial variation in yield across production areas. Application of the ED framework allowed identification of 1.1 M ha of oil palm managed by independent smallholders that can be targeted for sustainable intensification. SIGNIFICANCE: Our ED framework can facilitate evaluation and extrapolation of yield-improving technologies, increasing return to AR&D programs. In turn, intensification could help increase production on existing plantation area while avoiding conversion of fragile ecosystems. Our framework can be complemented with spatial socio-economic and environmental data to answer a wide range of questions at the intersection of agronomy, economy, and environment.