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Abstract Lake eutrophication remains a significant challenge for water‐quality management across the world. Many management strategies focus on reducing nutrient inputs, but other environmental factors can substantially influence the yield of algal biomass for a given level of nutrients. While various large‐scale studies have explored how different lake characteristics impact eutrophication, there remains a need to integrate these factors into a comprehensive model capable of assessing nitrogen vs. phosphorus limitation. In this study, we refine chlorophyll–nutrient relationships across the conterminous United States by considering auxiliary variables (i.e., temperature, lake depth, and nutrient enrichment) within a Bayesian hierarchical framework. We leverage over 4000 sampling events of 2755 different lakes from the National Lakes Assessments (2007–2022) to inform model development. We first consider auxiliary variables independently, exploring how they influence the intercept, slope, and critical nutrient ratio (nitrogen : phosphorus) in a regression to predict chlorophyll based on the limiting nutrient. Next, we integrate significant auxiliary variables into a comprehensive model for chlorophyll prediction. Results indicate that the critical nutrient ratio increases in relation to increased lake depth, and the slope of the nutrient–chlorophyll relationship increases with increasing temperature. We apply the model to map mean summer conditions across US lakes and find that 23% and 16% of lakes are strongly limited by phosphorus and nitrogen, respectively (i.e., at > 90% probability). These proportions, however, vary substantially across different subregions. Overall, the probabilistic modeling approach and results can serve as an effective tool to inform water resources management, especially at large spatial scales. 

ABSTRACT Feeding the growing human population sustainably amidst climate change is one of the most important challenges in the 21st century. Current practices often lead to the overuse of agronomic inputs, such as synthetic fertilizers and water, resulting in environmental contamination and diminishing returns on crop productivity. The complexity of agricultural systems, involving plant‐environment interactions and human management, presents significant scientific and technical challenges for developing sustainable practices. Addressing these challenges necessitates transdisciplinary research, involving intense collaboration among fields such as plant science, engineering, computer science, and social sciences. Five case studies are presented here demonstrating successful transdisciplinary approaches toward more sustainable water and fertilizer use. These case studies span multiple scales. By leveraging whole‐plant signaling, reporter plants can transform our understanding of plant communication and enable efficient application of water and fertilizers. The use of new fertilizer technologies could increase the availability of phosphorus in the soil. To accelerate advancements in breeding new cultivars, robotic technologies for high‐throughput plant screening in different environments at a population scale are discussed. At the ecosystem scale, phosphorus recovery from aquatic systems and methods to minimize phosphorus leaching are described. Finally, as agricultural outputs affect all people, integration of stakeholder perspectives and needs into research is outlined. These case studies highlight how transdisciplinary research and cross‐training among biologists, engineers, and social scientists bring diverse expertise to tackling grand challenges in sustainable agriculture, driving discovery and innovation. 

Abstract National nutrient inventories provide surplus phosphorus (P) estimates derived from county‐scale mass balance calculations using P inputs from manure and fertilizer sales and P outputs from crop yield data. Although bioavailable P and surplus P are often correlated at the field scale, few studies have investigated the relationship between measured soil P concentrations of large‐scale soil testing programs and inventory‐based surplus P estimates. In this study, we assessed the relationship between national surplus P data from the NuGIS dataset and laboratory‐measured soil test phosphorus (STP) at the county scale for Arkansas, North Carolina, and Oklahoma. For optimal periods of surplus P aggregation, surplus P was positively correlated with STP based on both Pearson (Arkansas:r = 0.65, North Carolina:r = 0.45, Oklahoma:r = 0.52) and Spearman correlation coefficients (Arkansas:ρ = 0.57, North Carolina:ρ = 0.28, and Oklahoma:ρ = 0.66). Based on Pearson correlations, the optimal surplus P aggregation periods were 10, 30, and 4 years for AR, NC, and OK, respectively. On average, STP was more strongly correlated with surplus P than with individual P inventory components (fertilizer, manure, and crop removal), except in North Carolina. In Arkansas and North Carolina, manure P was positively correlated with STP, and fertilizer P was negatively correlated with STP. Altogether, results suggest that surplus P moderately correlates with STP concentrations, but aggregation period and location‐specific factors influence the strength of the relationship. 

Abstract Phosphorus is essential to plant growth and agricultural crop yields, yet the challenges associated with phosphorus fertilization in agriculture, such as aquatic runoff pollution and poor phosphorus bioavailability, are increasingly difficult to manage. Comprehensively understanding the dynamics of phosphorus uptake and signaling mechanisms will inform the development of strategies to address these issues. This review describes regulatory mechanisms used by specific tissues in the root apical meristem to sense and take up phosphate from the rhizosphere. The major regulatory mechanisms and related hormone crosstalk underpinning phosphate starvation responses, cellular phosphate homeostasis, and plant adaptations to phosphate starvation are also discussed, along with an overview of the major mechanism of plant systemic phosphate starvation responses. Finally, this review discusses recent promising genetic engineering strategies for improving crop phosphorus use and computational approaches that may help further design strategies for improved plant phosphate acquisition. The mechanisms and approaches presented include a wide variety of species including not only Arabidopsis but also crop species such as Oryza sativa (rice), Glycine max (soybean), and Triticum aestivum (wheat) to address both general and species-specific mechanisms and strategies. The aspects of phosphorus deficiency responses and recently employed strategies of improving phosphate acquisition that are detailed in this review may provide insights into the mechanisms or phenotypes that may be targeted in efforts to improve crop phosphorus content and plant growth in low phosphorus soils. 

With diminishing availability of high-quality phosphate rock and increasing supply uncertainties, improving phosphorus (P) recovery, recycling, and waste reduction has become critical for sustaining agricultural production. We developed an integrated P cycling and soil dynamics model to quantify 7 circular strategies for reducing mineral P demand in the United States, using data for 91 major crops and 20 livestock types across 3,142 counties from 1866 to 2050. We show that soil residual P reuse has the largest potential to reduce mineral P demand in the United States. By 2023, total soil P stocks had accumulated to 99 Tg, equivalent to approximately 68% of mineral P inputs over 1866–2023. For 2024–2050, projections under various socioeconomic scenarios indicate that soil residual P reuse alone could potentially supply approximately 2.4 to 5.1 times projected US mineral P demand, with substantial residual P stocks accumulated in both cropland and pastureland soils. Recycling from sewage sludge and livestock and crop by-products could collectively offset an additional approximately 0.5 to 1.0 times mineral P demand, while food waste reduction could reduce requirements by approximately 0.3 times. Spatial analyses further highlight a mismatch between circular P availability and cropland P demand, with high mineral P avoidance potential concentrated in the South and West, but relatively low ratios of circular P supply to projected mineral P demand across most counties in the Midwest. These findings provide spatially explicit and decision-relevant insights into how circular P strategies can enhance the stability and resilience of US food systems under future resource constraints. 

Significant changes in gene expression were associated with unstable phosphorus removal. 

Phosphorus (P) is essential for plant growth, but excessive and continuous application of P fertilizers and animal manure has led to the accumulation of legacy phosphorus (legacy-P) in soils. While legacy-P presents a potential resource to support future agricultural demands, limited understanding of its chemical forms across different soil types hinders its sustainable management. This study aimed to characterize the chemical nature and storage potential of legacy-P in three contrasting soil types: acidic, organic, and calcareous. Key soil properties—including pH, organic matter, total P, Mehlich-3 P, and concentrations of aluminum (Al), calcium (Ca), iron (Fe), and magnesium (Mg)—were evaluated alongside P fractionation using a modified Hedley method. Furthermore, the soil P saturation ratio (PSR) was calculated to evaluate the relative saturation of soil sorption sites with P. Results showed considerable variability in Mehlich-3 P across soil types, ranging from 7–62% of total P in acidic soils, 1–8% in organic soils, and 3–47% in calcareous soils. Acidic soils were dominated by humic/fulvic-bound P (> 42%), organic soils by recalcitrant residual P (> 62%), and calcareous soils by Ca/Mg-bound P (> 69%), highlighting the influence of soil chemistry on P stability. Despite considerable variation among soil types in P fractionations, PSR results suggested that Ca/Mg-associated minerals play a greater role in retaining legacy P in organic and calcareous soils than Al- and Fe-associated minerals. In acidic soils, both mineral groups contributed similarly to P retention.