The concept of topographically controlled moisture redistribution underlies the conceptual model of soil development used by most researchers in the semi-arid northern Great Plains. The first part of this study explores the variability in the process of soil moisture redistribution, and its spatial distribution as it may be linked to topographic or pedogenic attributes. Recent advances in tillage research have shown that within cultivated landscapes tillage-induced redistribution of soils is the dominant erosion mechanism. The second part of this study attempts to validate the new model of tillage redistribution under Saskatchewan conditions.; The redistribution of soil moisture was monitored on three occasions between June 1997 and October 1998 using the redistribution of a chloride tracer as a surrogate for moisture redistribution. The results of the chloride tracer provided clear evidence for the direction and magnitude of water flow during the study period. The results confirm the distinction in the moisture redistribution process between depression-centred soils and upland soils. The primary control on the movement of the tracer at depression-centred soils was spring flooding in early 1998. Subsequent redistribution of the remaining tracer was dominated by discharge phenomena. Subsurface flow in upland soils is clearly anisotropic, with observed differences in the degree of lateral and vertical redistribution of the chloride mass between landform elements and between soil profile classes.; Two tillage experiments were conducted to evaluate the tillage process under Saskatchewan field conditions. The results of the tillage experiments were compared with the medium to long-term soil redistribution history as derived from cesium-137 redistribution. The cesium-137 results clearly show that the field-scale pattern of erosion at this Saskatchewan site corresponds to the characteristic pattern for tillage-induced erosion. Experimentally determined erosion values largely match or exceed those derived from the cesium-137 redistribution.; Cesium-137 derived erosion rates for divergent shoulders, divergent backslopes and convergent backslopes were 42.3, 32.4, and 10.8 Mg ha−1 y−1, respectively. Experimentally determined values for net tillage erosion in these landform elements using a surface applied granular tracer and the median slope gradient for each category were 44, 74, and 86 Mg ha−1 y−1, respectively. Net erosion values determined using an aqueous tracer applied to the soil surface had values of 16, 28, and 32 Mg ha−1 y−1 for divergent shoulders, divergent backslopes and convergent backslopes respectively. The comparatively low net erosion value for the divergent shoulder landform elements in the second experiment reflects the lack of a slope curvature factor in the erosion calculation.; These results confirm that the redistribution of water and the redistribution of soil materials by tillage are the basic controls on the distribution of soil taxa in this landscape.
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机译：地形控制的水分重新分配的概念是半干旱北部大平原大多数研究人员使用的土壤发育概念模型的基础。本研究的第一部分探讨了土壤水分再分配过程中的变异性及其空间分布，因为它可能与地形或成岩作用有关。耕作研究的最新进展表明，在耕地景观中，耕作引起的土壤重新分布是主要的侵蚀机制。本研究的第二部分试图验证萨斯喀彻温条件下耕作再分配的新模型。在1997年6月至1998年10月之间，用氯示踪剂的重新分配作为水分重新分配的替代品，对土壤水分的重新分配进行了3次监测。氯化物示踪剂的结果为研究期间水流的方向和大小提供了明确的证据。结果证实了以depression陷为中心的土壤与旱地土壤在水分再分配过程中的区别。示踪剂在以洼地为中心的土壤上运动的主要控制是1998年初的春季洪水。随后，剩余示踪剂的重新分布主要由排放现象控制。高地土壤中的地下流动显然是各向异性的，在地貌元素之间和土壤剖面类别之间，氯化物质量的横向和垂直再分布程度存在差异。进行了两次耕作实验，以评估萨斯喀彻温省田间条件下的耕作过程。将耕作试验的结果与源自铯137重分布的中长期土壤重分布历史进行了比较。铯137结果清楚地表明，萨斯喀彻温省这个地点的侵蚀规模模式与耕作诱发的侵蚀特征模式相对应。实验确定的腐蚀值在很大程度上符合或超过了铯137重分布所得出的值。 Csium-137得出的发散肩膀，发散后坡和会聚后坡的腐蚀速率分别为42.3、32.4和10.8 Mg ha -1 y -1 。使用表面施加的颗粒示踪剂对这些地貌要素进行的净耕作侵蚀的实验确定值，每种类别的中值坡度分别为44、74和86 Mg ha -1 y -1 < / super>。使用水示踪剂测定土壤表面的净侵蚀值分别为16、28和32 Mg ha -1 y -1 。分别收敛的后坡。在第二个实验中，发散的肩部地形元素的净侵蚀值相对较低，这反映了侵蚀计算中缺少坡度曲率因子。这些结果证实，水的重新分配和耕作对土壤物质的重新分配是该景观中土壤分类单元分布的基本控制。
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