Abstract. Understanding and assessing the spatiotemporal patterns in crop-specific phosphorus (P) fertilizer management is crucial for promoting crop yield and mitigating environmental problems. The existing P fertilizer dataset, derived from sales data, depicts an average application rate on total cropland at the county level but overlooks cross-crop variations. Conversely, the survey-based dataset offers crop-specific application details at the state level yet lacks inter-state variability. By reconciling these two datasets, we developed long-term gridded maps to characterize crop-specific P fertilizer application rates, timing, and methods across the contiguous US at a resolution of 4 km × 4 km from 1850 to 2022. We found that P fertilizer application rate on fertilized area in the US increased from 0.9 g P m^-2 yr^-1 in 1940 to 1.9 g P m^-2 yr^-1 in 2022, with substantial variations among crops. However, approximately 40 % of cropland nationwide has remained unfertilized in the recent decade. The hotspots for P fertilizer use have shifted from the southeastern and eastern US to the Midwest and the Great Plains over the past century, reflecting changes in cropland area, crop choices, and P fertilizer use across different crops. Pre-planting (fall and spring) and broadcast application are prevalent among corn, soybean, and cotton in the Midwest and the Southeast, indicating a high P loss risk in these regions. In contrast, wheat and barley in the Great Plains receive the most intensive P fertilizer at planting and via non-broadcast application. The P fertilizer management dataset developed in this study can advance our comprehension in agricultural P budget and facilitate the refinement in P fertilizer best management practices to optimize crop yield and reduce P loss. Datasets are available at https://doi.org/10.5281/zenodo.10700822 (Cao et al., 2024).

中文翻译：

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美国农田磷肥投入 (CMH-P) 的特定作物管理历史：自上而下和自下而上数据源的协调

摘要。了解和评估特定作物磷肥管理的时空模式对于提高作物产量和缓解环境问题至关重要。现有的磷肥数据集源自销售数据，描述了县级农田总面积的平均施用率，但忽略了作物间的差异。相反，基于调查的数据集提供了州一级特定作物的应用详细信息，但缺乏州际差异。通过协调这两个数据集，我们开发了长期网格地图，以 4 km × 4 km 的分辨率描述 1850 年至 2022 年美国本土特定作物的磷肥施用率、时机和方法。我们发现磷肥美国施肥面积的施用量从1940年的0.9 g P m ^-2 yr ^-1增加到2022年的1.9 g P m ^-2 yr ^-1，不同作物间差异很大。然而，近十年来，全国约40%的农田仍未施肥。近一个世纪以来，磷肥使用热点已从美国东南部和东部转移到中西部和大平原，反映了耕地面积、作物选择和不同作物磷肥使用的变化。中西部和东南部地区的玉米、大豆和棉花普遍采用预播（秋季和春季）和撒施，表明这些地区磷流失风险较高。相比之下，大平原地区的小麦和大麦在种植时和通过非播撒施用获得了最密集的磷肥。本研究开发的磷肥管理数据集可以增进我们对农业磷预算的理解，并有助于完善磷肥最佳管理实践，以优化作物产量并减少磷损失。数据集可在 https://doi.org/10.5281/zenodo.10700822 上获取（Cao 等人，2024）。