Soil physical properties of a Chernozemic clay loam after 24 years of beef cattle manure application

Limited information exists on the influence of long-term application of beef cattle manure on soil physical properties in the Canadian prairies. A site on a clay loam soil (Dark Brown Chemozem) at Lethbridge was used to determine the effect of increased rates of manure application on selected soil physical properties in 1997 and 1998. The manure (from an unpaved feedlot) was applied annually in the fall for 24 yr at one, two and three times the 1973 recommended rates under dryland (0, 30, 60, 90 Mg ha(-1) wet basis) and irrigation (0, 60, 120, 180 Mg ha(-1)). There was a significant (P < 0.05) decrease in the sand content of soil (0-10, 10-20 cm) with increased rates of manure application; and an increase in clay content for the 60 and 120 Mg ha(-1) rates compared to the control under irrigation. There was a significant and negative linear relationship between increased rates of manure application and bulk density (0-5, 10-15 cm) for most seasons, and season affected bulk density values for a given manure rate. Penetration resistance (0-14 cm) was unaffected by increased rates of manure application under dryland. Under irrigation, it was significantly reduced at only the 3.5 cm and 10.5 cm depths in 1997, and at only the 3.5 cm depth in 1998. Air permeability was generally unaffected by increased rates of manure application, except for the 0-5 cm depth under irrigation, where it was significantly lowered at the highest application rate. Soil temperatures (0, 10, 20 cm) were lower under increased rates of marnure application at the 10 and 20 cm depths in the spring and summer under dryland, and they were higher at these two depths in the winter. Under irrigation, soil temperatures were lower with increased rates of manure application at the 20-cm depth in the spring, and they were higher at the 20-cm depth in the fall, and at the 0- and 20-cm depths in the winter. Overall, soil physical properties generally had a neutral or positive response to 24 yr of annual manure application at high rates, and should not cause any detrimental effects to the soil's physical condition.