The Role of Variable Rate Technology (VRT) in Modern Agriculture: A Review

Abstract

The main aim of this publication is to discuss the concept of variable rate technology (VRT), and its components associated with variable rate application of water, fertil­izer, and other agricultural inputs. Fertilizer application is influenced by soil parameters as well as geographical variation in the field. The selection, rate, and distribution of nutrients at the ideal distance from the crop and soil depth determine nutrient management. Depending on the soil's characteristics and the geographical variation in the field or plants, variable rate technology (VRT) enables the application of inputs at a certain rate, time, and location. There are two methods for putting VRT into practice: map-based and sensor-based. The sensor-based strategy, which employs appropriate sensors to evaluate soil and crop properties while on the go, calculates the quantity of nutrients needed per unit area/plant, and uses microcontrollers that apply appropriate algorithms to regulate fertilizer flow with the necessary amount of nutrients. In map-based approach; Grid sampling and soil analysis are used to create a prescription map. According to the soil and crop conditions, the microcontroller regulates the desired application rate. The sensor-based VRT system includes a fertilizer tank, sensors, GPS, microcontroller, actuators, and other components, whereas the map-based system does not require an on-the-go sensor. Both approaches of VRT for fertilizer application in orchards and field crops are reviewed in this paper.