Wireless sensors for stratified soil microwave scanning applied to precision quality agriculture

The paper presents an automatic wireless sensor platform that allows precision soil investigations in order to verify punctual seasonal variations in soil water content. In this way, it is possible to keep the plants nourishment cycle under precise control, correlating it to temperature, humidity and rain variations. The sensing unit is constructed by means of couples of microwave radiators, and the water content percentage is evaluated thanks to a continuous measurement of the received power. The design procedure is carried out by identifying the most suitable solution, in terms of operational frequency, dimensions of radiators and their relative distance, balancing the decreased mismatching effect with the increased propagation attenuation caused by the presence of the water. Experiments carried out in collaboration with the Case Basse winery in Montalcino are presented and discussed.