Gridded 5-arcmin, simultaneously farm-size- and crop-specific harvested area for 56 countries

Abstract

Abstract. Farms are not homogeneous. Smaller farms generally have different planted crops, yields, agricultural input, and irrigations compared to larger farms. Mapping farm size could facilitate studies to quantify how water availability and climate change affect small and large farms respectively. Given the lack of gridded farm-size specific data, this study aims to develop a global gridded simultaneously farm-size- and crop-specific dataset of harvested area. We achieved it by downscaling a best-available dataset, which collected direct measurements on crop and farm size, using crop maps, cropland extent, and dominant field size distributions for 2010. Uncertainties in crop maps were explicitly considered by using two crop maps separately during downscaling. Due to data availability, our downscaled maps cover 56 countries accounting for half of the global cropland. Based on the two different crop maps, we have one 5-arcmin gridded, simultaneously farm-size- and crop-specific dataset of harvested area for 11 farm sizes, 27 crops, and 2 farming systems and the other one for 11 farm sizes, 42 crops, and 4 farming systems. The downscaled maps show major planted crops and irrigation change along with farm sizes which support previous findings. Validations show well consistencies with observations on farm-size specific oil palm from satellite images, farm-size specific irrigation from household surveys, and previous studies that map farm size but are not crop-specific. We observed some uncertainties at the grid cell level and found conclusions at the country-level are robust to these uncertainties including the uncertainties from the crop maps. Our downscaled maps will help to explicitly include farm size into global agriculture modeling. The source data, code, and downscaled maps are open-access and free available at https://doi.org/10.5281/zenodo.5747616 (Su et al., 2022).