of land-related characteristics of a region and are fundamentally carried out to facilitate the extrapolation of The northern Great Plains have long been dominated by conveninformation from the research site to like conditions tional tillage systems and cereal-based rotations including summer fallow. Over the last decade, however, the use of conservation tillage elsewhere. Conceptually, the research procedure is gensystems has markedly increased and, through improved moisture stor-erally as follows: Agronomic research is first carried age, has provided an opportunity for more diversified extended rotaout under controlled conditions resulting in a particular tions including oilseed, pulse, and forage crops throughout the region. finding or findings. Based on the finding(s), a model is Considerable research is being carried out to assess the adaptability developed to predict what comparable finding(s) would of these new crops and to develop appropriate management strategies. be under the breadth of conditions (soil, climate, and Typically, this type of agronomic research is carried out at plot-sized management) found in the region. Finally, the land reresearch sites, with the findings then being extrapolated to surrounding source inventory documents where specific conditions regions where growing conditions are thought to be reasonably similar.occur or in other words, provides spatial information to Because the environment itself largely dictates the success of a particuapply the model and effect the extrapolation. lar cropping system, extrapolation requires knowledge of the environmental conditions of the region and, in particular, the interaction of This paper documents the distribution of the major environmental components of soil and climate in relation to specific land resource areas, or agroecoregions, of the northern crop requirements. This paper describes 14 agroecoregions in theGreat Plains and provides an initial framework for the northern Great Plains and provides an initial framework for extrapoextrapolation of pertinent agronomic information from lating agronomic information at broad regional scales. Because climate the research site to areas of similar environmental condiis the dominant crop production factor in the region, most of the tions. Each agroecoregion is described in terms of its agroecosystems represent broad climatic zones. Each agroecoregion soil and landscape characteristics, with a particular focus is described in terms of its soil and landscape characteristics, with a being given to likely key environmental parameters reparticular focus being given to likely key environmental parameters lated to the production of oilseed, pulse, and forage related to the production of the new oilseed, pulse, and forage crops crops being introduced in the region. Climate data are being introduced in the region.

The northern Great Plains have long been dominated by conventional tillage systems and cereal‐based rotations including summer fallow. Over the last decade, however, the use of conservation tillage systems has markedly increased and, through improved moisture storage, has provided an opportunity for more diversified extended rotations including oilseed, pulse, and forage crops throughout the region. Considerable research is being carried out to assess the adaptability of these new crops and to develop appropriate management strategies. Typically, this type of agronomic research is carried out at plot‐sized research sites, with the findings then being extrapolated to surrounding regions where growing conditions are thought to be reasonably similar. Because the environment itself largely dictates the success of a particular cropping system, extrapolation requires knowledge of the environmental conditions of the region and, in particular, the interaction of environmental components of soil and climate in relation to specific crop requirements. This paper describes 14 agroecoregions in the northern Great Plains and provides an initial framework for extrapolating agronomic information at broad regional scales. Because climate is the dominant crop production factor in the region, most of the agroecosystems represent broad climatic zones. Each agroecoregion is described in terms of its soil and landscape characteristics, with a particular focus being given to likely key environmental parameters related to the production of the new oilseed, pulse, and forage crops being introduced in the region.

No abstract

P. 2005. An empirical model for estimating carbon sequestration on the Canadian prairies. Can. J. Soil Sci. 85: 549-556. There is a need to develop verifiable algorithms that can be easily applied to estimate carbon sequestration in soils. A simple process-based empirical model, driven primarily by soil texture and crop residue input, was developed to account for changes in soil organic carbon (SOC) in Chernozemic soils on the Canadian prairies. The model was used to estimate SOC change under no-till and continuous cropping compared with conventional tillage and rotations with fallow. Using this model, C sequestration due to continuous cropping compared with fallow-containing rotations was determined to be 0.09 Mg C ha -1 yr -1 for the Brown and Dark Brown, and 0.05 Mg C ha -1 yr -1 for the Black and Dark Gray/Gray soil zones. The rate of C sequestration as a result of continuous cropping was positively related to the frequency of fallow, which decreases on the prairies from the Brown, Dark Brown, and Black to the Dark Gray/Gray soil zones. Using this model average C sequestration when conventional tillage was converted to no-till, was 0.13, 0.23, 0.34, and 0.25 Mg C ha -1 yr -1 for the same soil zones, respectively. Combined gains due to no-till and continuous cropping in comparison with conventional tillage and fallow-containing rotations were determined to be 0.22, 0.32, 0.39, and 0.30 Mg C ha -1 yr -1 for the Brown, Dark Brown, Black and Dark Gray/Gray soil zones, respectively. Based on Agricultural Census of Canada data in 1996 and 2001, the amount of "C sequestered" due to the adoption of no-till was estimated to be 1.23 million Mg of C in 1996 and 1.72 million Mg of C in 2001, which is approximately 10% of the total greenhouse gas emissions from the agricultural sector in Canada. This simple process-based empirical model could serve as a useful tool for soil scientists to use in assessing soil sustainability and C sequestration in the Canadian prairies. It would also assist policy makers in understanding how various scenarios of improved management will influence future greenhouse gas emissions on agricultural soils. , ce qui correspond à environ 10 % des émissions globales de gaz à effet de serre de l'agriculture canadienne. Ce modèle empirique simple pourrait s'avérer utile aux spécial-istes de la science des sols qui souhaitent évaluer la pérennité des sols et la séquestration du carbone dans les Prairies canadiennes. Il aiderait aussi les auteurs de politiques à comprendre l'incidence des diverses méthodes visant à améliorer la gestion des terres sur les futures émissions de gaz à effet de serre par les terres cultivées. For personal use only.