Nutrients in the nexus

Abstract

Synthetic nitrogen (N) fertilizer has enabled modern agriculture to greatly improve human nutrition during the twentieth century, but it has also created unintended human health and environmental pollution challenges for the twentyfirst century. Averaged globally, about half of the fertilizer-N applied to farms is removed with the crops, while the other half remains in the soil or is lost from farmers' fields, resulting in water and air pollution. As human population continues to grow and food security improves in the developing world, the dual development goals of producing more nutritious food with low pollution will require both technological and socioeconomic innovations in agriculture. Two case studies presented here, one in sub-Saharan Africa and the other in Midwestern United States, demonstrate how management of nutrients, water, and energy is inextricably linked in both small-scale and large-scale food production, and that science-based solutions to improve the efficiency of nutrient use can optimize food production while minimizing pollution. To achieve the needed large increases in nutrient use efficiency, however, technological developments must be accompanied by policies that recognize the complex economic and social factors affecting farmer decision-making and national policy priorities. Farmers need access to affordable nutrient supplies and support information, and the costs of improving efficiencies and avoiding pollution may need to be shared by society through innovative policies. Success will require interdisciplinary partnerships across public and private sectors, including farmers, private sector crop advisors, commodity supply chains, government agencies, university research and extension, and consumers.

Dilemma of nitrogen management for future food security in sub-Saharan Africa – a review

“…Soil N mining could be overestimated if N inputs from irrigation water, rainfall, crop residue, biological N fixation, and atmospheric deposition are ignored, but could be underestimated if losses through leaching, erosion, runoff, volatilisation, and denitrification are ignored (Majumdar et al 2016). The N footprint tool is useful for identifying hotspots of N losses to the environment, simulating mitigation options, and informing policy decisions for good N management through raising awareness of social responsibilities Davidson et al 2016). The application of the tool showed that in many countries the largest portion of the N footprint was associated with food production, with N accumulation in selected countries like the United States of America, whereas N mining occurred in countries like Tanzania in SSA (Hutton et al 2017).…”

Improving resource productivity at a crop sequence level

“…In fact, considering the relationship between N Input -N Output and Output N proposed by Norton et al (2015), EI is in a situation of "Farmer wins, Environment wins" and our FP treatments are in the situation of "Farmer loses, Environment loses", which is coincident with the average estimation for Argentina. Similarly, following Davidson et al (2016), EI is close to the situation of "Food security wins, Environment wins", but FP aligns with "Food security wins, Environment loses -soil degradation".…”

Science in the Supply Chain: Collaboration Opportunities for Advancing Sustainable Agriculture in the United States

“…Currently, this process involves engaging scientists from member universities, NGOs, and the USDA and in some instances can involve broader engagement of the scientific community (Snyder, 2015) and specific contracts for meta‐analyses or model applications. Beyond engaging scientists in direct evaluation of metrics, such metric improvements over the long term may increasingly depend on the development and availability of models capable of accurately simulating both complex biophysical and biogeochemical processes, including fate of applied nutrients (Davidson et al, 2016) and the dynamics of soil carbon (Paustian et al, 2016), and management practices that influence these processes.…”