Improving Phosphorus Use Efficiency in Cropland to Address Phosphorus Challenges by 2050

Phosphorus (P) is a nutrient critical for growing crops and is fundamental to meet the growing food demand. However, excess P lost from crop production to the Earth system leads to environmental and social concerns from local to global scale. Besides the urgent need to feed the worlds growing population, two major challenges for P use and management are P depletion and nutrient pollution. One critical strategy to address these P challenges is to improve P use efficiency (PUE, the output-input ratio of P in a defined system) in crop production. The success of this strategy depends on improving regional and crop-level PUE with advanced technologies and effective management strategies, and an understanding of relevant socioeconomic and ecological drivers influencing regional and global PUE. Many efforts have been devoted to quantifying P budgets (the input and output of the crop production system) at different spatial scales and improving nutrient management practices on farms. Few studies, however, have examined the historical trajectories of PUE and their socioeconomic and ecological drivers on a national scale or quantified the impacts of PUE improvement on addressing P challenges. Here we present a unique database of P budgets and PUE by country and crop type for 1961-2014, analyze the temporal and spatial patterns of P use, examine the contribution of potential drivers for PUE, and make a projection of future P budgets under three scenarios with different PUE improvement levels. We found that PUE has been significantly affected by a countrys development stage, nitrogen use efficiency (NUE), fertilizer to crop price ratio, average farm size, crop portfolios, and agricultural machinery. To address the P depletion and nutrient pollution challenges by 2050 while increasing crop production, global PUE in cropland must increase to 68-81%, which poses varying challenges, opportunities, and strategies among countries.