Fertiliser on-farm decision tool: Optimising the use and reducing the environmental burden of fertigation

"Agriculture depends on soil nutrients (primarily nitrogen, phosphorous, and potassium) to optimise plant development and ultimately yield. Soils contain such nutrients naturally, but growing and harvesting crops results in nutrients becoming depleted, leading to plants suffering from nutrient deficiency and decreasing yields. It is therefore crucial for food security and efficient crop production to replace the natural supply of nutrients in the soil to enable the continuous cultivation of crops. These nutrients can be added from a variety of sources - organic matter, chemical fertilisers, and certain plants (as traditionally done by crop rotation) - ensuring maintenance of soil health and fertility, enabling continuous growth of nutritious and healthy crops at high yields. Chemical fertilisers are the most efficient way to supply nutrients to the soil and have the highest cost benefit. Our entire agricultural system depends on the application of fertiliser in one form or another; it would not be possible to maintain the world's population at its current level without it. Especially nitrogen is of prime importance for farmers and food production, as the most important nutrient limiting crop development and yield, and also contributing the largest cost to crop production.

However, this nitrogen is rarely efficiently managed; 110 million tons of nitrogen is applied onto fields every year, but only about a quarter of this makes it into plants, partly due to the poor nitrogen use efficiency of crops. Over application of fertiliser results in leaching of this excess into watercourses, and approximately 80 million tons of nitrogen is estimated to flow into the world's waterways every year.

General overuse of nitrogen fertiliser and to some lesser extent other nutrients such as phosphate and potassium, causes eutrophication and toxic algal blooms in water systems, leading to death of aquatic organisms from oxygen depletion in the water by the algae. It also promotes denitrification by microorganisms, leading to the release of nitrous oxide, a potent greenhouse gas, into the atmosphere. Production of inorganic fertilisers also requires a large input of energy which further contributes to greenhouse gas emission as well as fossil fuel depletion.

This project aims to develop a decision tool that will enable farmers to better optimise the quantity of fertiliser applied to crops, lowering use and increasing the percentage of nutrients taken up by plants and therefore resulting in less nitrogen (and phosphate and potassium) being released into the environment."