Effects of land use change and crop rotation practices on farmland ecosystem service valuation

Farmland can provide various ecosystem services such as food production, groundwater recharge, and carbon storage. However, the overall value of farmland ecosystem services and differences in their spatial distribution are rarely studied, particularly with regard to farmland with crop rotations. In this study, we developed an assessing framework for appraising the overall value of ecosystem services of farmland with crop rotations on the basis of Costanza's global ecosystem service valuation method. Changhua County in central Taiwan is used as a case study to estimate the impact of land use change on its farmland ecosystem services. We also applied the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model to analyze the spatial distribution of individual ecosystem services. Results from the global ecosystem service value method indicates that land use change in the study area caused a steady decline in overall farmland ecosystem service value between 1981 and 2021. However, if the practice of farmland crop rotation is included, the proposed method for evaluating ecosystem services of farmland indicate an increase in total ecosystem service value (ESV). The overall ecosystem services of farmland with crop rotations assessed was between 1.27 and 1.69-fold higher than the gross domestic product (GDP) for farming in the region and between 17 and 45.3-fold higher than the agricultural expenditure reported by the local government. The findings of this study also suggest local government can reference the spatial distributions of ecosystem service to dynamically adjust subsidies and resources for farmland, thereby enhancing agricultural governance and achieving sustainability goals.