Annual time-series 1-km maps of crop area and types in the conterminous US (CropAT-US): cropping diversity changes during 1850–2021
Abstract. Agricultural activities have been recognized as an important driver of land use and cover changes (LUCC) and have significantly impacted ecosystem feedback to climate, air, and water quality by altering land surface properties. A reliable historical cropland distribution dataset is crucial for understanding and quantifying the legacy effects of agriculture-related LUCC. While several LUCC datasets have the potential to depict cropland patterns in the conterminous US, there remains a dearth of a high-resolution dataset with crop type details over a long period. To address this gap, we reconstructed historical cropland density and crop type maps from 1850 to 2021 at a resolution of 1 km×1 km by integrating inventory datasets and gridded LUCC products. The results showed that the developed dataset is highly consistent with the county-level inventory data, with an R2 approaching one and RMSE less than 3 Mha (million hectares) at the national level. Temporally, the US total crop acreage has increased by 118 Mha from 1850 to 2021, primarily driven by corn (30 Mha) and soybean (35 Mha). Spatially, the hotspots of cropland shifted from Eastern US to the Midwest and the Great Plains, and the dominant crop types (corn and soybean) moved toward the Northwest of the US. Moreover, we found the US cropping system diversity experienced a significant increase from 1850s to 1960s, followed by a dramatic decrease in the recent six decades under the intensified agriculture. Generally, the developed dataset could facilitate the spatial data development in delineating crop-specific management practices and enable the quantification of cropland change impacts.
