Water and Plant Nutrition: Managing Two Inseparable Resources for a Food-Secure World
Water security and food security are inseparable. Agriculture accounts for approximately 70% to 72% of global freshwater withdrawals, making it central to achieving sustainable water management. There is no credible pathway to Sustainable Development Goal (SDG) 6 - ensuring clean water and sanitation for all - without transforming the way water and nutrients are used in agriculture. Equally, there is no pathway to SDG 2 on zero hunger in a world of escalating water insecurity or insufficient nutrient use. Fertilizers and improved agronomy are essential to sustaining the agricultural productivity needed to feed a growing global population, making the efficient management of water and plant nutrients increasingly important to future food security. The two agendas succeed together or fail together.
Yet in many countries, the governance and management of agricultural resources remain fragmented: water, plant nutrition, soil health, and crop productivity are often addressed through separate policies and programs, limiting opportunities to improve both water use efficiency and water quality.
This white paper argues that managing water and plant nutrition together is one of the most effective - and most underestimated - opportunities to strengthen agricultural resilience while making more efficient use of increasingly scarce water resources.
The argument rests on a simple fundamental agronomic reality: water and nutrients are closely linked. Water enables crops to absorb, transport and assimilate nutrients, while balanced plant nutrition (supplying crops with the right combination and amounts of plant nutrients according to crop needs and local soil conditions) helps plants regulate their water use, develop deeper root systems, and withstand water stress. Water Use Efficiency (how effectively plants convert available water into biomass or yield) and Nutrient Use Efficiency (the proportion of applied or available nutrients taken up and converted into useful crop output) are mutually reinforcing rather than independent objectives. At the same time, losses of nutrients - particularly nitrogen and phosphorus - from agricultural systems can degrade the freshwater, groundwater, and coastal ecosystems on which all life depends. Reducing those losses requires water and nutrients to be managed as interconnected resources rather than as separate inputs.
The white paper examines this water-plant nutrition nexus through a suite of solutions and identifies the enabling conditions needed to support the adoption and scaling of approaches that are already technically feasible: aligning governance around shared water and nutrient outcomes (Section 3.1), investing in integrated and circular resource systems (Section 3.2), measuring and rewarding combined performance (Section 3.3), making integrated management practical for farmers (Section 3.4), and organizing partnerships around implementation (Section 3.5).
