Micro-UAVs (unmanned aerial vehicles) with a total weight below 5 kg are interesting alternative carriers for agricultural applications. Compared to standard airborne aerial surveys, UAVs are much more flexible and weather independent. As a result, micro-UAV surveys will pave the way for affordable, current and accurate geo-information. This article deals with the general conditions and challenges for unmanned aerial vehicles that can be used for agricultural land monitoring. The article includes an overview of the structural characteristics and parameters of a UAV that has been developed for environmental monitoring by the Institute of Transport Vehicle Technology of Riga Technical University, and a detailed review about surveying fields with UAV systems is carried out.