This paper presents an adaptive network mechanism for a smart farm system by using LoRaWAN and IEEE802.11ac protocols. Generally, the internet of things (IoT) system for agriculture application is used in an en-vironment where significant interferences can occur. These interferences can disrupt the network performance ofthe system. In this paper, an adaptive network mechanism is designed to improve the network performance ofthe system, in order to achieve a more reliable smart farm system. Specifically, the proposed adaptive networkmechanism is implemented in the application layer. The system has the ability to adjust a protocol based on thenetwork condition. For instance, the IEEE 802.11ac is suitable for transmitting data which require high data ratesuch as image or video. On contrary, the LoRaWAN protocol is suitable for sending data that only have smalldata packets such as sensor reading data. An adaptive mechanism, which combines advantages of both protocols,leads the system to achieve reliability while performing the monitoring task. The system has been evaluated forthe real deployment scenario. The result demonstrates that the proposed system brings the reliability in terms ofaverage latency and total gathered number of sensors’ data.