Impact of agronomic management on the soil microbiome: A southern Australian dryland broadacre perspective

To maintain sustainable broadacre farming in the future, a better understanding of soil microbiome functions and processes associated with adapting agronomic management practices will be key. This is primarily due to the irreplaceable roles of the soil microbiome in soil and plant interactions, human health and ecosystem functions and stability. We approached this challenge by reviewing how different land management practices influence soil microbial communities. The important role that the soil microbiome plays in cropping systems is analyzed in the context of an overview of changes in land management over the past two decades using southern Australian dryland farming as a case study. Many major changes in management have occurred in this system during this time, including (i) reduction in tillage, with a corresponding increase in direct drilling and stubble retention; (ii) inclusion of oilseeds and pulses in cereal-dominated rotation systems; (iii) decrease in the pasture-dominated grain production systems; (iv) increased use of agrochemicals; (v) different soil amelioration applications and (vi) development of innovative agricultural technology. We review the overarching role of climate extremes in impacting agronomic management practices in southern Australian farming systems. In all, we demonstrate the complex interplay between land management changes and the activity, diversity and functions of the soil microbiome, with reference to changes in agronomic management practices.