Soil moisture sensors can measure soil moisture content. Growers use that information, for example, to prioritize irrigation of fields: which ones should be irrigated first, which can wait? This is especially important in situations where the fields of a farmer are spread over a wider region. There the transport and start of the irrigation set is a limiting factor in farm management, it might even be impossible to irrigate all fields that need it. Furthermore, optimal irrigation is needed for optimal uptake of minerals by plants. If uptake is not optimized, growth is affected plus minerals stay in the cultivation layer and may leach in case of heavy rainfall or in case of excessive irrigation (double negative effect!).
So, soil moisture has a strong direct and indirect effect on the profitability and sustainability of fertilizer management. A specific challenge for soil sensors is to install them in a way that they are representative for the field in which they are situated. The soil around the sensors should have a good connection, but not too firm; they should not be installed in a border and also not in places where the machines can destroy them. To cope with these challenges, different designs are available; mostly complex and expensive but also swarms of small sensors are under development. In the next years possibilities will expand, giving new impulses for precision agriculture.