Development of a Wireless Sensor Network for Soil Moisture Monitoring in Oil Palm Plantations

Abstract

1. Oil palm is one of Indonesia's most strategic plantation commodities, with soil moisture being a critical factor determining plant productivity. Conventional monitoring methods that rely on manual inspection are inefficient, time-consuming, and unable to provide continuous real-time data across wide plantation areas. This study presents the development of a Wireless Sensor Network (WSN) system for real-time soil moisture monitoring in oil palm plantations using the ESP32 microcontroller and capacitive soil moisture sensors. The system employs the MQTT communication protocol to transmit sensor data from three distributed measurement nodes to a cloud-based dashboard accessible via web browser and mobile application. System testing was conducted over a period of seven days on a 2-hectare oil palm plantation, covering sensor accuracy tests, wireless communication range tests, and response time evaluations. Comparative testing between sensor readings and a calibrated reference soil moisture meter showed a mean absolute error (MAE) of 2.73%, which is within acceptable tolerance for agricultural monitoring applications. The wireless transmission success rate reached 98.4% within a range of up to 50 meters, and average system response time was recorded at 1.42 seconds. The results demonstrate that the developed WSN system is technically reliable, practically deployable, and cost-effective for continuous soil moisture monitoring in oil palm plantation environments.