Key points are not available for this paper at this time.
ABSTRACT: It is generally believed that soil erosion is the greatest single factor causing loss of soil productivity. However, the exact nature of these losses in terms of the concentrations of nutrients removed in windblown sediment vs. the parent soil from whence the sediment originated has not been adequately quantified. Two field sites were established in southern Alberta (one in 1990, one in 1993) as validation sites for the Wind Erosion Prediction System (WEPS) model. As part of this project, more than 400 windblown sediment samples (at heights of 10-100 cm above the soil surface) were collected from a total of 29 erosion events. Analysis of windblown sediment samples presented an opportunity to compare the nutrient content of windblown sediment with that of the adjacent surface soil where it originated. Additionally, the effects of natural wind erosion on crop productivity were monitored At Site 1, total N in windblown sediment trapped at 25-cm height showed an average (13 events) enrichment ratio of 1.11, while organic C in windblown sediment showed an average enrichment ratio of only 1.02 compared with soil from the erodible surface. At Site 2, the average (4 events) total N enrichment ratio was 1.08 and the average organic C enrichment ratio was 1.05. The depositional area at Site 1 showed nutrient enrichment compared with the erodible surface. Changes in soil productivity due to natural erosion were reflected in spring wheat (Triticum aestivum L.) yields in 1992, but not in canola (Brassica napus L.) yields in 1993. Spring wheat yields showed a linear decrease with increased severity of erosion. For every 1 m increase in the distance from non-erodible surface there was a decrease of 3.6 kg ha−1 in grain yield. The results provide further evidence that every effort should be made by producers and government agencies to prevent erosion of the thin layer of surface soil that ensures the fiituie sustainability of agriculture on the semiarid Canadian prairies.
Larney et al. (Wed,) studied this question.