Evaluating the effectiveness of variable rate technology of herbicides and chemical fertilizers on reducing environmental pollutants, Economic Costs and energy use in wheat production

• Variable-rate fertilizers and herbicides reduced total energy use in wheat. • N, P, K fertilizers and herbicides decreased by 22–82 % under VRT. • GWP decreased by ∼20 % with variable-rate application. • Freshwater ecotoxicity and eutrophication dropped by 65 % and 34 %. • VRT reduced endpoint impacts on human health, ecosystems, and resources. Precision agriculture, as an advanced technology for optimal management of agricultural inputs, plays a key role in increasing agricultural resource efficiency and reducing environmental impacts. So, the aim of the present study was to evaluate the effectiveness of Variable Rate Technology (VRT) of herbicides and chemical fertilizers on environmental indicators of wheat production. The study was conducted during the 2023–2024 cropping season on experimental farm of Pars Soil and Water Engineering Services Development Company in Karaj, Iran. Two scenarios were evaluated: (1) the conventional method of chemical fertilizer and herbicide application, and (2) the simulated VRT method based on weed distribution maps obtained from drones and fertilizer application based on field experiments. LCA was performed according to ISO 14,040 standards using the ReCiPe2016 method to measure environmental impacts in two mentioned scenarios. The results showed that the VRT method reduced nitrogen use by 22.22 %, phosphorus by 38.89 %, potassium by 77 %, and herbicides by 82.40 %, leading to a reduction in global warming potential from 22,202.73 to 17,691.21 kg CO₂ equivalent (20.32 %), soil acidification (22.77 %), and freshwater ecotoxicity (65.02 %). The VRT method reduced total energy consumption by about 18 % compared to the conventional method and improved energy efficiency and energy ratio. These achievements emphasize the vital role of precision agriculture technology in achieving sustainable agriculture and optimizing input use.