Early improvement of soil health under cropping systems including perennial forage crops and dairy cattle slurry in a cool humid climate

In the past decades, dairy farms in eastern Canada have dedicated more land to annual crops and less to perennial forages. Concurrently, there has been a shift in cattle manure management from solid to liquid forms. Our objective was to determine the early response of soil health indicators (soil aggregate stability to water, carbon [C] and nitrogen [N] in microbial biomass, particulate organic matter, and nonfractionated soil) to two crop types (annual crops vs. perennial forages) and N sources (mineral fertilizer, dairy cattle slurry, and biological N fixation) in the 0–10 cm surface soil at three locations (Ontario, Quebec, and Nova Scotia). Despite some variability in their response, most of the indicators pointed to an improvement in soil health within three years of implementation of perennial forages and/or dairy cattle slurry applications. Particulate organic matter and microbial biomass were generally more responsive to the experimental treatments than soil organic matter. Changes in soil C and N were found at the three locations within the first three years of the experiment. For instance, C concentrations were 7%–31% higher under perennial forages and/or dairy cattle slurry in comparison to annual cropping and/or mineral fertilization. Improvement in soil health was generally greater under perennial forages fertilized with dairy cattle slurry, than under annual crops receiving mineral fertilizer. The response of soil C concentration tended to be more pronounced at sites with lower initial soil C concentrations, and faster in the soil with the highest clay content.