Land Use Change Effects on Soil Quality in Prince Edward County, ON
Soils play a key role in Earth System function. When original vegetation cover is converted to cultivated land, soils often become degraded and lose their productivity potential. We examined the effects of land-use change on a clay/clay loam soil on a farm in Ameliasburg on the northern part of Prince Edward County. Three cover types were examined: perennial sod (for lawns), perennial switchgrass (potential bioengery crop) and undisturbed forest. For each soil type, cores to a depth of 40cm were collected along three random 30m transects (at 8, 16 and 24m), then divided into 10cm increments and combined along one transect according to depth. Soil quality was assessed by analyzing various soil physical and chemical properties. Bulk density was almost two-fold higher (1.5 vs. 0.82 g/cm3) in both grass systems compared to the forest, but only in the 0-10cm layer, likely due to surface compaction associated with land management. Soil pH was slightly lower in the forest compared to the switchgrass field. The sod and switchgrass fields showed losses of ~33% and ~53% organic matter, respectively in contrast to the forested area. The largest differences for organic matter and total carbon were in the top 20cm. Soil C: N ratios were highest for the forested site and lowest for the sod field. Although perennial grass systems often enhance soil quality compared to extensively tilled sites, it appears that long-term (10y) sod production has led to a decline in some, but not all, soil quality measures, particularly soil organic matter and carbon content.