Signal Processing and Electronic Communication in Agriculture: an Iot-based Automatic Fertigation System

Abstract

The world population is increasing at an exponential rate and the demand for food is also increasing exponentially. Application of farm inputs such as water, fertilizer, pesticides and labour must avoid wastage and ensure efficient use of resources.

Fertigation supplies water and liquid fertilizer through the same channel to plants. Using a drip irrigation setup for fertigation allows the root zone of the plant to be continuously supplied with nutrients and water throughout the farm season. Conventionally, fertigated systems are controlled using pre-set timers to turn on and off fertilizer injectors and irrigation pumps and also to set the frequency and duration of supply. Therefore, fertigation management is usually based only on predictive algorithms or historical data which may not be accurate for all situations.Development of a microcontroller-based fertigation management system within the Nigerian (Sub-Saharan Africa) region using a Capacitive Soil Moisture Sensor and JXCT-IOT Frequency Domain Reflectometry (FDR) Soil Nitrogen Sensor is presented. The sensors are placed in the soil around the root region of plants to enable a microcontroller monitor the soil properties, determine how much water or nutrient the plant needs and supply the amount needed through a drip irrigation framework. Tap water and Urea solution are placed in inside separate reservoirs and supplied to the plant through Solenoid valves controlled by the microcontroller. Furthermore, an Internet of Things (IOT) client (Blynk IOT) was integrated with the fertigation system so that the fertigation process as well as the soil state could be monitored and controlled remotely. The data read from the sensors as well as the state of the Solenoid valves were sent over the internet to be stored on the Blynk servers. Website and mobile (Android) dashboards were also created using the Blynk IOT platform to display the states of the valves and the sensor readings.The automatic fertigation system was found to be functional. The system keeps the Soil Moisture and Nitrogen content between the recommended ranges: Moisture content between 25% and 46% and the Nitrogen content between 20 mg/kg and 30 mg/kg for cucumber crops. Fertigation events occurred every morning between 5 and 6 am. Use of signal processing for control of farm inputs has been demonstrated. Electronic measurements and communication have been applied to agriculture. Efficient use of resources is guaranteed. The system reduces labour cost and has the potential of increasing the farm yields.