The Role of Phosphorus in Reducing the Impact of Climate Change in Agriculture

Climate change driven by the accumulation of greenhouse gases (GHG) in the atmosphere is projected toincrease average global surface temperatures, influencing agricultural production and nutrient cycling. Phosphorus (P), a key nutrient for plant growth, can both contribute to and reduce the effects of climate change. Climate change and P management are interrelated, as climate change will influence optimal P management while P fertilizer can both help in ameliorating and adapting to climate change effects on agriculture and the environment and contribute to direct and indirect GHG emissions. Greenhouse gases are emitted during phosphate rock extraction, as well as during the production transport and application of P fertilizer. Emissions during production could be reduced by improving energy efficiency, using alternative, non-fossil energy sources, or possibly using emerging technologies for synthesis of the ammonia used in production. To reduce the amount of indirect greenhouse gas emissions linked to P manufacture, it is important to optimize the efficiency of P fertilizer as the less P that is mined, processed, transported and applied to the field per unit of agricultural production, the less risk there is of both GHG emissions and off-site transport. While production and transport of P fertilizer can contribute to climate change, efficient P management can reduce negative effects of climate change and may contribute to reductions in GHG emissions and to climate change adaptation. Optimal P management is needed to support carbon sequestration in soil, to allow plants to benefit from increasing CO2 concentrations, to reduce risk of indirect GHG emissions, to reduce P movement to water bodies and to enhance resiliency of crops to climate stress. Proper nutrient management, including P management, plays a key role in Climate Smart Agriculture, Low-Carbon Agriculture and Sustainable Intensification, that are different approaches to encouraging optimal crop productivity while minimizing the contribution of agriculture to climate change. Managing P fertilizer in a changing environment requires use of the 4R principles to select the rate, source, timing and placement combination best suited to the site-specific agronomic and environmental conditions.