A spatially explicit dataset of agriculture liming across the contiguous United States

Abstract. Agricultural lime has historically been applied to croplands in the United States to counteract soil acidification and enhance soil fertility, with important consequences for crop productivity and Earth’s carbon cycle. Previous work on agricultural liming has largely focused on either region-specific case studies or national-level estimates of total application rates, leaving a major gap in understanding the spatial variability in lime application. This study addresses this gap by presenting the first spatially explicit dataset of agricultural lime application across the contiguous United States. The dataset comprises state-level data for 1930–1950 and a more detailed county-level dataset for 1954–1987, enabling comprehensive spatial-temporal analyses at multiple scales. Counties in the Midwest region exhibited the highest total amounts of lime applied in the latter half of the twentieth century, reflecting intensive agricultural activity. These counties were characterized by higher overall lime application rates (amount of lime applied per unit of limed area each year) but relatively lower liming frequency (ratio of limed area to total agricultural land area each year). In contrast, counties in the southeastern coastal region exhibited lower lime application rates per unit of limed area but more frequent lime applications. We used a machine learning framework, to elucidate key environmental and agricultural drivers of lime application. Our results show that the total amount of lime applied, as well as the application rate and frequency, are strongly associated with regional climatic conditions and soil properties. However, we also found evidence that agricultural management practices (such as crop production, fertilizer use, and soil pH recommendations) played a key role in shaping liming applications. Spatiotemporal integration of the data product results in a revised national estimate of total lime application, with a range of 15–25 million tons (Mt) per year. This study establishes a critical observational baseline for assessing the potential of agricultural lime application as a climate mitigation strategy and highlights the need for further research into its long-term environmental impacts.