|
|||||
|
|
Management effects on soil C storage on the Canadian prairies |
|
| Authors: | H H Janzen C A Campbell R C Izaurralde B H Ellert N Juma W B McGill R P Zentner |
| Institution: | a Agriculture and Agri-Food Canada, Lethbridge Research Centre Lethbridge, Alta. Canada T1J 4B1 b Agriculture and Agri-Food Canada, Semi-arid Prairie Agricultural Research Centre Swift Current, Sask. Canada S9H 3X2 c Department of Renewable Resources, Faculty of Agriculture, Forestry, and Home Economics, University of Alberta Edmonton, Alta. Canada T6G 2H1 |
| Abstract: | The Canadian prairie, which accounts for about 80% of Canada's farmland, has large reserves of soil organic carbon (SOC). Changes in the size of the SOC pool have implications for soil productivity and for atmospheric concentrations of CO2, an important ‘greenhouse gas'. We reviewed recent findings from long-term research sites to determine the impact of cropping practices on SOC reserves in the region. From this overview, we suggest that: (1) the loss of SOC upon conversion of soils to arable agriculture has abated; (2) significant gains in SOC (typically about 3 Mg C ha?1 or less within a decade) can be achieved in some soils by adoption of improved practices, like intensification of cropping systems, reduction in tillage intensity, improved crop nutrition, organic amendments, and reversion to perennial vegetation; (3) changes in SOC occur predominantly in ‘young' or labile fractions; (4) the change in SOC, either gain or loss, is of finite duration and magnitude; (5) estimates of SOC change from individual studies are subject to limitations and are best viewed as part of a multi-site network; and (6) the energy inputs into agroecosystems need to be included in the calculation of the net C balance. The long-term sites indicate that Canadian prairie soils can be a net sink for CO2, though perhaps only in the short term. These sites need to be maintained to measure the effects of continued agronomic evolution and predicted global changes. |
| Keywords: | Carbon Greenhouse gas Carbon dioxide Tillage Crop rotation Fertilizer |
| 本文献已被 ScienceDirect 等数据库收录！ | |