The International Plant Nutrition Institute has released a 4R Plant Nutrition Manual that highlights the four rights of fertilizer practices, namely the right source, right rate, right time and right place. The manual devotes separate chapters to discuss each of the four rights and their scientific principles as they relate to the most effective and efficient use of fertilizer.
Currently, the use of commercial fertilizer is responsible for 40 to 60 percent of the world’s food production. But as economic, environmental and social issues for food production are emerging in different parts of the world, this manual proposes a new vision for plant nutrient stewardship on a sustainable foundation. This vision seeks to integrate the four unified rights with the site-specific factors of crop, climate, soil, water quality, economics, labor supply and logistics. One chapter is devoted to practices that support the implementation of all four rights by assessing the soil’s capacity to supply nutrients, such as scouting for visual symptoms, soil testing, plant analysis and on-farm research. A mix of learning modules and case studies demonstrate the universality of the 4R nutrient concept through its application to diverse cropping systems within small enterprises, large commercial farms and plantations.