Influence of Long-Term (9 yr) Composted and Stockpiled Feedlot Manure Application on Selected Soil Physical Properties of a Clay Loam Soil in Southern Alberta

ABSTRACT

Land application of composted feedlot cattle (Bos taurus) manure may have differential effects on soil physical properties compared to stockpiled manure because of the differences in the composition, particle size, and decomposability of these materials. Our objective was to determine the effect of long-term (9 yr) composted (CM) versus stockpiled (SM) manure application on selected soil physical properties. Intact soil cores were taken from CM, SM, and unamended control treatments from a long-term field experiment in the fall of 2007. Soil bulk density, plant available water (PAW), and soil water retention and hydraulic conductivity at low (0–34 kPa) water potentials were determined on the soil cores. Water retention at the 0 to 10 cm depth was significantly (P ≤ 0.05) greater for SM than CM between -5 and -34 kPa, suggesting an increase in transmission and storage pores in the SM treatment. In contrast, water retention at the 10 to 20 cm depth was greater for CM than SM at -1 and -5 kPa, indicating an increase in transmission pores for this treatment. Based on the results of our study, application of CM instead of SM will likely not improve most soil physical properties measured, with the exception of water retention at certain water potentials in the top two depths. However, organic amendments will likely improve most soil properties measured compared to unamended soils.

ACKNOWLEDGMENTS

Field and laboratory assistance was provided by Raygan Boyce. Dan Reynolds of Agriculture and Agri-Food Canada in Harrow, Ontario kindly provided advice and guidance on soil physical measurements.