|Collins, Harold - Hal|
Submitted to: Canadian Journal of Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/11/2003
Publication Date: 2/1/2004
Citation: Paul, E.A., Collins, H.P., Paustian, K., Elliott, E.T., Frey, S., Cole, C.V., Juma, N., Janzen, H., Campbell, C.A. 2004. The effect of management on the dynamics and storage capacity of soil organic matter in the canadian prairies. Canadian Journal of Soil Science. 84:49-61. Interpretive Summary:
Technical Abstract: Long-term treatments in Alberta and Saskatchewan were sampled to 1 m with analysis for bulk density organic and inorganic C, N, particulate organic C and N, and CO2-C evolved during long-term mineralization. The use of fallow lowered SOC in all soils especially in the sub-boreal previously forested Typic Cryo Boralf site (Breton). Incorporation of crop rotations, fertilizers and manures raised the N content of this soil to 173 percent that of the adjacent forest. The high SOC,Udic Borall at the Melfort research station represents a soil that is still above steady state relative to its SOC content under cultivation. Particulate organic C and N varied with soil type and were not good indicators of total soil organic matter. The difference in particulate organic C (POM-C) between treatments at each site was related to differences (R2=0.68) in soil C and represented 47 percent of this C.The use of incubation to allow the soil biota to mineralize labile, soil N and C provided the most sensitive indicator of management effects. The Breton, cultivated plots showed a five-fold difference in CO2-C release relative to a two-fold difference in SOC. The soils from the continuously cropped, fertilized, wetter, Udic Boralls (Melfort and Indian Head) released 60 percent as much CO2 -C as the native site. The cultivated, aridic Boralls under fertilization and crop rotation were similar to the native sites in their CO2 release characteristics. Differences in CO2 evolution with treatment (delta CO2 - C) were highly correlated to POM-C early in the incubation indicating that in these soils POM-C represents short-term SOC storage. Differences in POM-C were sensitive to manure additions. Management for optimum soil fertility may differ from management for C sequestration.