Agroecosystems are comprised of environmental compartments where associated microbial communities interact with one another. These microbial communities, called microbiomes, inhabit livestock, insects, and plants. Microbiomes are also present in the soil and watersheds. Clarifying the nature and extent of microbial interactions between compartments both at intra-farm and global scales can promote sustainable production systems, healthier animals, increased crop yields, and safer meat products. Early research on microbiomes was hindered by a lack of expertise and the high cost of molecular sequencing. However, these limitations have been largely resolved with advances in and reduced costs of sequencing technologies. In this paper, we summarize sequencing and bioinformatics approaches, and review the crucial roles of diverse microbiomes in livestock, plants and soil, as well as pollinators and pest insects. These crucial roles include nutrient cycling, nutrient acquisition, metabolism of toxins and enhanced host immune function. Additionally, we examine potentially undesirable effects of microbiomes associated with climate change and agri-food production such as their role in the release of greenhouse gases from cattle and their impact on meat safety and spoilage. By increasing the awareness of microbiomes and the growing ease with which they can be studied, we hope to foster a greater adoption of microbiome research. Further understanding of the diverse effects and interactions of microbiomes will advance our efforts to increase agricultural production while reducing its negative environmental footprint, thus making the agroecosystems more sustainable.