The Science of 4R Nutrient Stewardship for Phosphorus Management across Latitudes

Abstract

When phosphorus (P) fertilizers were introduced, the main goals were to increase the productivity and profitability of agricultural crop production. Over time, other goals have been added: to minimize losses affecting water quality, to increase recycling, to reduce consumption of the limited resource, to improve soil health, and to enhance biodiversity. The science of 4R nutrient stewardship addresses these multiple goals. Across latitudes, temperate and tropical soils differ in their chemical reactivity with P. Legacies of cumulative P surplus, however, differ more widely across longitudes than latitudes. As of 2016, the ratio of cumulative P surplus to current crop P removal ranged from 18 in the United States to 31 in Brazil to 63 in western Europe. The opportunity to use these legacies to improve P use efficiency—and to reduce risk of harm to water quality—in all three regions depends on the improvement of tools to assess the availability of soil P to crops. Science focused on balanced crop nutrition and systematic analysis of crop response has the opportunity to improve farm‐level tools to guide responsible management of P. Transitions in 4R practice depend on engagement between science and industry not only at the farm level but along the full agricultural value chain. Whole‐system changes may be necessary to enable practitioners to implement 4R nutrient stewardship strategies that can in turn result in major improvements to full‐chain use efficiency of the earth's P resources. Core Ideas The science of 4R nutrient stewardship supports multiple ecosystem services. Intensive crop production often requires a legacy of P surplus. Legacies of cumulative P surplus vary among regions. Transitions in P management require science–industry engagement.

Increasing the Effectiveness and Adoption of Agricultural Phosphorus Management Strategies to Minimize Water Quality Impairment

“…Nutrient management (i.e., planning the source, rate, timing, and method P application), for example, is regarded as the main practice to avoid agricultural P losses and will be seen by most farmers as a valuable tool to help them apply P most profitably. Nutrient management is not discussed in detail in this paper as this topic is covered separately in this special section (Bruulsema et al, 2019; Grant and Flaten, 2019); we instead focus here on how applied P becomes vulnerable to all loss pathways depending on the source, rate, placement, and timing.…”

Phosphorus mirabilis: Illuminating the Past and Future of Phosphorus Stewardship

“…Bruulsema et al (2019) discuss opportunities to use P legacies in crop production to increase PUE and decrease water quality impairment. A significant improvement in PUE can, in fact, be accomplished through the development of a new generation of fertilizer products and application technologies, according to Weeks and Hettiarachchi (2019).…”

“…A unified promotion of the “4Rs” of nutrient stewardship (right source, right rate, right time, and right place, taking into account local site variations) by researchers, nongovernmental organizations, and agricultural supply chain stakeholders, has been a positive move forward to think globally, but act locally (Bruulsema et al, 2019; International Plant Nutrition Institute, 2014; International Fertilizer Association, 2009; Sharpley et al, 2016). Bruulsema et al (2019) note that the initial goal of increasing the productivity and profitability of agricultural crop production via 4R‐based P stewardship has been expanded to include the goals of minimizing P runoff, increasing recycling of P to reduce consumption, and improving soil health and agroecosystem biodiversity. Successful transitions in P management will require science–industry engagement, and Bruulsema et al (2019) further describe how 4R nutrient stewardship addresses these multiple goals.…”

“…Bruulsema et al (2019) note that the initial goal of increasing the productivity and profitability of agricultural crop production via 4R‐based P stewardship has been expanded to include the goals of minimizing P runoff, increasing recycling of P to reduce consumption, and improving soil health and agroecosystem biodiversity. Successful transitions in P management will require science–industry engagement, and Bruulsema et al (2019) further describe how 4R nutrient stewardship addresses these multiple goals. However, the continued development of 4R practices depends on engagement between science and industry not only at the farm level but along the full agricultural value chain (Bruulsema et al, 2019).…”

“…Successful transitions in P management will require science–industry engagement, and Bruulsema et al (2019) further describe how 4R nutrient stewardship addresses these multiple goals. However, the continued development of 4R practices depends on engagement between science and industry not only at the farm level but along the full agricultural value chain (Bruulsema et al, 2019). …”