Long-Term Grazing Effects on Fescue Grassland Soils

Abstract

Highlight Very heavy grazing of fescue grassland range at Stavely, Alberta, compared to light grazing, changed the color of the Ah horizon from black to dark brown and the pH from 5.7 to 6.2, reduced the percent organic matter, reduced percent total P but increased NaHCOs-soluble P, and increased soil temperature but decreased percent soil moisture. Trends indicated that soil of the very heavily grazed field was being transformed to a soil characteristic of a drier microclimate. The importance of soil as a reservoir elf nutrients and moisture for the production of forage has been recognized since the beginning of range management as a science (Klemmedson, 1970). With the development of the range conditioa metho,d of range analysis (Dyksterhuis, 1949; Smoliak et al., 1969), soil became an object of study in terms of soil-plant relations, its potential to produce a vegetative crop, and its resistance to damage. But, in the Fescue Grassland ranges of western Canada, there is still a dearth of soil infolrmation for use in management planning and in the improving or rehabilitating of deteriorated or brush-infested ranges. The purpose of our study was to determine the nature of edaphic change resulting from the grazing of fescue grassland range by cattle.

The effects of grazing and burning on soil and plant nutrient concentrations in Colombian p�ramo grasslands

“…The net result of less vegetation cover and higher soil density are higher maximum temperatures in the top soil as a result of less isolation by vegetation and more decomposition of organic material as a result of these higher temperatures and less acidic conditions. Probably, soil moisture content also will be lower (less C, compression, evaporation, Dormaar et al, 1989;Johnston et al, 1971;Moorhead and Reynolds, 1993;Nadelhoffer et al, 1991;Swift et al, 1979;Seastedt et al, 1991).…”

“…Finally, the change in species composition of the vegetation might be explained by the dominance of grazing and burning tolerant species in the competition for the higher soil nutrient levels (Chapin, 1980;Milchunas et al, 1988;Negi et al, 1992). The resulting grassland is likely to consist of a compact and dry soil, with a short growing vegetation which is nevertheless attractive for grazers because of the higher overall palatability (Johnston et al, 1971;McNaughton et al, 1988;M ilchunas and Lauenroth, 1993). Seastedt et al (1991) noted the shift in competition for light to competition for nutrients when burning and grazing are introduced in tall grasslands.…”

“…Soil samples with a higher bulk density had a lower moisture content. It is likely that higher density is caused by trampling and that a lesser volume and lower C content after compression of the soil caused a lower moisture content (Dormaar et al, 1989;Johnston et al, 1971). The relation between density and moisture content was absent in the dry season, indicating that the soils were not saturated then.…”

Seasonal Dynamics and Defoliation Impact on Herbage Yield in Aspen Boreal Habitats of Alberta

“…Numerous studies have demonstrated the effects of fertilizer, legumes, and defoliation on grasslands in western Canada (Johnston et al 1971;Smoliak et al 1972;Ukrainetz et al 1988;Pearen and Baron 1996;McCartney et al 1999). Most of these studies have taken place on nutrient rich soils in the Black Chernozemic soil zone, rather than the less fertile Gray Luvisolic soils of the Boreal Mixedwood where many commercial game ranching enterprises are located (McCartney et al 1999).…”

Long-term effects of burning Festuca and Stipa-Agropyron grasslands

“…Litter insulates the soil against incident solar radiation (Rauzi 1960, Willms et al 1986 thereby reducing evaporation (Weaver andRowland 1952, Hopkins 1954) and increasing soil water. Litter also insulates the soil, creating cooler temperatures in summer and warmer temperatures in winter (Johnston et al 1971). Burning removes litter which in turn causes cascading effects of reduced soil water, increased plant water stress, and reduced production in Fescue Prairie (Redmann 1978, Grilz and Romo 1994 Production in drier parts of the Northern Mixed Prairie is associated with amounts of litter; production is maximized with maximum amounts of litter (Willms et al 1986(Willms et al , 1993.…”