Agriculture, and natural resources associated to its development like water, soils and forests, have a relevant role in the future of countries and environmental conservation. The optimization of these resources is made with the implementation of technological strategies and tools that make it possible. In this sense, we developed a monitoring prototype for agronomic variables in cassava crops (Manihot Esculenta Crantz) in the Atlántico department (Colombia) based in WSN using Z1 motes as hardware platform and the temperature and soil moisture sensor SHT11. The operating system used was Contiki, and the routing protocol was RPL. The Network Performance Metrics evaluated were packet loss, RSSI (Received Signal Strength Indicator), LQI (Link Quality Indicator) and network convergence time. Then, a deployment model using Schläfli notation to determine the location and number of nodes, also we calculated the coverage range of the nodes to keep network uniformity. With these calculations, we obtained the linkage budgets between specks, and results were validated with RadioMobile software. Then, test fields were made in a cassava crop located in the city of Manati, Atlántico. Finally, with the help of server client architecture XAMPP, all data was stored and visualized through SIMCA (Agricultural Crop Information and Monitoring System), a web application developed by authors.

Today, through the monitoring of agronomic variables, the wireless sensor networks are playing an increasingly important role in precision agriculture. Among the emerging technologies used to develop prototypes related to wireless sensor network, we find the Arduino platform and XBee radio modules from the DIGI Company. In this article, based on field tests, we conducted a comparative analysis of received strength signal intensity levels, calculation of path loss with ''log-normal shadowing'' and free-space path loss models. In addition, we measure packet loss for different transmission, distances and environments with respect to an ''Arduino Mega'' board, and radio modules XBee PRO S1 and XBee Pro S2. The tests for the packet loss and received strength signal intensity level show the best performance for the XBee Pro S2 in the indoor, outdoor, and rural scenarios.

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Rainfall monitoring networks are key elements for the development of alerts and prediction models for communities at risk of flooding during high intensity rainfall events. Currently, most of these networks send the precipitation measurement to a data center in real-time using wireless communication protocols, avoiding travel to the measurement site. An Early Warning System (EWS) for pluvial flash floods developed in Barranquilla (Colombia), used the GPRS protocol to send rain gauge data in real-time to a web server for further processing; however, this protocol has a high consumption of energy and also high maintenance costs. This article carried out an evaluation in terms of link budget, link profile, energy consumption and devices costs of three low-power wireless communication protocols, Zigbee, LoRaWAN and Sigfox, to determine which one is the most suitable for the EWS of the city of Barranquilla. To perform the evaluation, a wireless sensor network was designed and characterized for Zigbee and LoRaWAN with Radio Mobile tool taking into account the measurement points implemented with GPRS network. The evaluation included the power consumption of Zigbee, LoRaWAN and Sigfox. From the results of simulations, LoRaWAN and Zigbee network has similar radio signal received and the LoRaWAN network obtains the least losses per path. As for power consumption, the LoRaWAN devices has the lowest energy consumption, as well as, the LoRaWAN network sensor nodes are cheaper. Finally, the protocol with the best general performance was LoRAWAN, since complies with the communication, consumption and cost requirements.

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