Using IoT resources to enhance the accuracy of overdrain measurements in greenhouse horticulture

Climate change has already shown its negative impact that has on agriculture and food production, particularly because of rainfall deficit or excess, temperature changes and other associated environmental variations not amenable to sustainable agriculture. Greenhouse horticulture has proven to be an effective way of reducing the negative effects of climate change on vegetable production, but still represents a challenge for farmers, because the behavior of most plant species grown in protected environments is markedly different from open field cultivation. To increase the understanding of plant growth in protected crops, Internet of Things (IoT) capabilities were integrated into a greenhouse, thus providing a platform for researchers that allows them to take decisions at the right time about irrigation, moisture requirements and nutrients. The designed system consists of electronic circuitry, sensors, mobile communication, actuators and software running in the cloud. The functionality of the system was tested in a cucumber vegetable production in a greenhouse, where the data acquired from environmental variables, substrate conditions, and overdrain measurements are sent over the Internet for their remote analysis by researchers. In the particular case of overdrain measurements, the traditional way of data gathering using manual procedures with pH and conductivity probes was enhanced by the introduction of drain gages, valves and probes with automatic data acquisition, and the application of an online Kalman filter to improve the accuracy of a low precision liquid flow meter. Preliminary results are encouraging and seem to point for continuing the development of efficient tools for decision taking about vegetable production in greenhouse horticulture.