Decision‐making factors for variable rate application of seed and fertilizer in precision agriculture systems: A review

Abstract Input management practices within precision agriculture systems have enabled grain and oilseed producers to apply agricultural inputs variably, facilitating resource, yield, and profit optimization. Despite significant progress in variable rate technologies, research comparing different methodologies and comprehensive guidelines to assist producers in their decision‐making processes is still lacking. This research article aimed to identify and summarize the suggested decision‐making factors for determining variable seed rates and variable fertilizer applications. A systematic review of the literature from the last 2 decades was conducted, summarizing various approaches within precision agriculture related to variable rate applications in canola ( Brassica napus L.), maize ( Zea mays L.), soybean [ Glycine max (L.) Merr.], and wheat ( Triticum aestivum L.). Findings revealed a wide range of decision‐making factors guiding variable rate applications, from site‐specific soil characteristics to complex data‐driven recommendations. Focus crops were maize and soybean in terms of variable seeding rates, while nitrogen was the only fertilizer source discussed. Most articles appeared to address a single specific decision‐making factor, with limited comparisons drawn between different methods. The results underscore the complexity of variable rate decisions, especially in terms of the influence of weather, highlighting the overarching impact that rainfall has on grain and oilseed production in dryland systems. To maximize the effectiveness of variable rate applications across diverse production systems and justify the initial investment in these technologies, it is essential to develop adaptable, context‐specific guidelines for seed and fertilizer management.