Optical sensors for site-specific nitrogen fertilisation in agricultural crop production

For agricultural crop production it is essential to apply the right amount of nutrients, especially nitrogen. If the plants receive too little nitrogen fertiliser, the yield and the economical profit will be reduced, while overfertilisation will lead to unnecessary expenses and environmental problems. In order to take the in-field variability of nitrogen demand into account, tractor-mounted optical sensors are used to measure the current nutrient status. Together with a variable-rate fertiliser distributor these sensors allow an optimised, environmentally friendly variable nitrogen application. Today, various systems are commercially available or under development. These systems either analyse the fight reflected by the crop or alternatively measure the fluorescence of chlorophyll pigments after excitation with a laser source. Extensive field trials show the economic and ecologic potential of this technology.