ABSTRACT
Nitrogen (N) has a decisive effect on plant yield. When applied in low quantities, yields are reduced, leading to reduced production, not sufficient to meet increased food needs, especially in economically poor countries. When applied in excessive quantities, which is usually the case in economically rich countries, it creates serious environmental problems. The management of this element to achieve the optimum plant yields without burdening the environment is therefore crucial. The traditional form of N management does not take into account the variability of the soil and follows the whole-field approach, leading to the application of excessive quantities of N, which entails an increase in production costs and environmental problems. Today, innovative techniques have been developed that deal to a large extent with soil variability. These techniques are based on different forms of sensors or soil that detect soil variability in real time and allow the quantity of applied N to be differentiated according to changes in soil properties or plants that record their needs in N in any position in the same field. This chapter describes the evolution of the technologies, developed to date, which enable these real N needs to be recorded through the soil or plants and differentiated application of N in real time, based on the actual needs of plants. Finally, an example is given of the development and implementation of such approaches by a relevant study carried out in Thessaly, central Greece within the framework of the HORIZON2020 research program.
