Vegetation and Soil Responses to Grazing Simulation on Riparian Meadows

Abstract

Riparian areas have not responded consistently to grazing systems, suggesting that more knowledge is needed to explain how different areas respond to specific stresses. Several studies were conducted to determine herbaceous plant response to simulated grazing on riparian areas. One low-elevation redtop (Agrostis stofoniferu L.) site in Oregon and 2 high-elevation sedge (Curer spp. L.) sites in Idaho were studied for 3 years. Several combinations of defoliation, compaction, nutrient return, and season of use were examined. The redtop community responded to spring, fall, or spring-fall defoliations by maintaining or increasing the following year's aboveground biomass production. The sedge communities maintained or decreased the following years's biomass production after spring, mid summer, or late summer defoliations. An increase in forbs occurred in 1 sedge community following spring defoliations to l-or S-cm residual stubble heights. The most consistent plant response among areas was reduction in height growth and biomass production following compaction treatments. When both defoliation and compaction are considered, it appears that spring, fall, or spring and fall grazing to a 5 cm stubble height on the redtop site would not decrease riparian herbage production. In contrast, when defoliation, compaction, and nutrient return effects are considered in the mountain meadow sedge-dominated communities, grazing once annually during the growing season to a 5-cm stubble height in the spring, or to a IO-cm stubble height in late summer, or at a utilization rate exceeding 30% of the total annual biomass production can reduce herbage production significantly. Results suggest that many of the land management agency riparian guidelines would maintain biomass productivity in these sedge-dominated communities.

Restoring degraded riparian meadows: Biomass and species responses

“…Clipping had little or no effect on biomass in comparison to the control. These results are consistent with those of a similar study that indicated defoliation to a 10 cm stubble height did not significantly affect biomass production (Clary 1995). Also, the Mean cover (SE) for 1996 and 1998 and the ratio of the 1998/1996 cover values for 6 of the dominant species.…”

A mechanical hoof for simulating animal treading under controlled conditions

“…Bulk density and macroporosity were determined following the fifth treading at the end of decreases in maoroporosity, and decreases in pasture production, as a result of animal treading, have also been reported by others, with the magnitude of treading effects varying, depending on soil type and treading periods (e.g., Gifford & Dadkhah 1980;Tollneretal. 1990;Clary 1995;Ledgardetal. 1996;Drewry et al 1999;Singleton & Addison 1999).…”

Seasonal grazing affects soil physical properties of a montane riparian community

“…led to degradation of soil physical characteristics (Clary 1995), which in turn can lead to altered hydrologic properties (Bryant et al 1972), increased sediment production (Warren et al 1986b), and a decline in vegetation productivity and vigor (Dadkhah and Gifford 1980, Leininger and Trlica 1986).…”

“…Little quantitative information is available describing how soils and infiltration in riparian areas respond to activities in different seasons (Tierney 1992), or on how quickly soils recover from changes that result from grazing livestock (Bohn and Buckhouse 1985, Warren et al 1986b, Tierney 1992, Clary 1995. Specifically, timing of grazing and length of rest periods have been indicated as areas where further investigation is needed to help determine best management practices Hawkins 1978, Warren et al 1986a).…”