A review on variable rate technologies for fertilizer application status, challenges and future prospects

Global factors such as population growth, increasing food demand, limited land resources and environmental concerns have intensified the need for sustainable and efficient fertilizer management in agriculture. Conventional uniform fertilizer application often results in nutrient imbalances, reduced yields, soil degradation and environmental pollution, highlighting the necessity for advanced site-specific practices. Variable Rate Technologies (VRT) has recently gained attention due to their potential to optimize fertilizer use efficiency, enhance crop productivity and reduce ecological risks. To address existing gaps related to adoption challenges, high initial investment, technological adaptability, and policy support, a systematic review of VRT systems including map-based, sensor-based, UAV-assisted and automated applicators was performed. The reviewed studies indicated that VRT can increase nutrient use efficiency by 20-40%, reduce nitrogen losses significantly, and improve soil health, while also offering economic benefits through fertilizer savings of up to 40%. Despite these advantages, constraints such as high costs, lack of awareness among farmers, and unsuitability of imported technologies for smallholder conditions limit wider adoption, particularly in developing countries. Future prospects lie in integrating low-cost sensors, machine learning decision tools, IoT-based monitoring and government-backed initiatives to make VRT accessible and scalable. With proper adaptation to local conditions, VRT has the potential to transform fertilizer application into a more precise, sustainable and economically viable practice, thereby ensuring food security and environmental sustainability for the future.