The application of plant protection products (PPPs) at variable rates has gained prominence as a key strategy in precision agriculture (PA), promoting the rational use of inputs (water, fertilizers, pesticides) while improving crop yields and mitigating the environmental impacts (e.g., drift, evaporation, run-off). Despite the rapid growth of variable-rate application (VRA) systems, large-scale adoption remains fragmented, with strong emphasis on technological development and limited integration of economic, operational, and environmental assessment. To critically assess how research on VRA of PPPs has evolved and where significant knowledge gaps persist, this study conducted a bibliometric and scientometric analysis of the relevant literature aimed at mapping the scientific evolution, identifying trends and analyzing the gaps that limit the consolidation of the VRA domain. By identifying these imbalances, this study provides a critical reference framework to drive future research toward more robust, comparable, and globally relevant VRA solutions in PPP applications. Scopus and Web of Science (WoS) databases were used, encompassing English-language scientific articles published between 2005 and 2025. The search strategy combined two sets of terms related to PPP application and variable-rate systems. The VOSviewer software was utilized for quantitative analysis. The bibliometric analysis assessed the temporal and geographical distribution of publications and identified the most productive authors, while the scientometric analysis visualized keyword co-occurrence networks and citation patterns among authors and countries. The results indicated that research activity culminated in a significant peak during the 2020–2024 period, with an upward trajectory for partial data of 2025. The United States and China emerged as leading contributors to scientific output. The most frequent keywords revealed the advancement of technologies such as pulse width modulation (PWM) technology, sensors, and automation. Although this research area is rapidly expanding, its consolidation still requires greater geographical participation and deeper technical exploration across various research fronts.
Vargas et al. (Sat,) studied this question.