Chang, Chi (AAFC, Lethbridge, AlbertaLethbridge Research Centre, Agriculture and Agri-F, ‘Lethbridge, AB, T1J 4B1, Canada; Phone: 403 317-2220; Fax: 403 317-2187; Email: chang@agr.gc.ca)
C. Chang *, X. Hao, G. Clayton
Animal manure application to land has been shown to increase soil organic carbon content and changes in soil physical, chemical, and biological properties. Land application of animal manure, either in raw or composted form, is also considered part of strategies for C-sequestration. However, the rates of change in soil organic C content (concentration) and the rates of increase in the total amount of soil organic C accumulation in the soil profile in relation to the total cumulative amount of organic C applied through feedlot cattle manure application are not well known. A long-term cattle feedlot manure land application field study was initiated in the fall, 1973 in Lethbridge Alberta, Canada. The annual manure application rates were 0, 30, 60 and 90 Mg ha-1 for nonirrigated and 0, 60, 120 and 180 Mg ha-1 (wet weight) for irrigated land. The results showed that soil organic C content (concentration) in the surface 15 cm of soil increased curve linearly with cumulative amount of organic-C applied through manuring under both non-irrigated and irrigated conditions. The total amount of soil organic C increase in the soil profile from 0 to 60 cm depth interval also increased with cumulative organic C applied. The rate of increase in surface soil organic C content and total amount of soil organic C in the profile can be calculated. This information is useful in evaluating C sequestration through long-term manure application.