Wheat yield and soil properties reveal legacy effects of artificial erosion and amendments on a dryland Dark Brown Chernozem

Erosion leads to substantial loss of soil productivity. To abate such decline, amendments such as manure or fertilizer have been successfully employed. However, the longevities of erosion and soil amendment legacy effects are not well quantified. In 1957, a Dark Brown Chernozem soil at Lethbridge, AB, was land-levelled, creating three degrees of topsoil removal or erosion: noneroded, moderate erosion, or severe erosion. Two amendment studies (1980-1985 and 1987-1991) were superimposed on the erosion treatments. Both studies were cropped to spring wheat (Triticum aestivum L.) from 1993-2010 to examine legacy effects of erosion and soil amendments on wheat yield and soil properties. Without amendment, mean wheat yield under moderate erosion was 40% of the noneroded treatment, whereas severe erosion was 34% of the noneroded treatment, 36-42 yr (1993-1999) after erosion. Under moderate or severe erosion, the restorative power of manure diminished substantially in the first 10-15 yr following cessation of addition, but then levelled off resulting in wheat yields up to 35% higher than equivalent nonamended treatments. Legacy effects of erosion (54 yr) and amendment (27-31 yr) on soil organic carbon and total nitrogen were also observed.