Stubble height as a tool for management of riparian areas

Abstract

Stubble height, a measure of the herbaceous vegetation remaining after grazing, has been widely used in recent years to gage the impacts of grazing use in riparian areas. Stubble height is a short-term management guide that should only be applied to help attain long-term ecological objectives; it should not be thought of as a long-term management objective.Maintaining a minimum stubble height helps preserve forage plant vigor, retain sufficient forage to reduce cattle browsing of willows (Salix spp.), stabilize sediments, indirectly limit streambank trampling, maintain cattle gains, and provide an easily communicated management criterion. Based on limited specific research of riparian system response and on knowledge of the characteristics of how cattle graze, a 10-cm residual stubble height is recommended by the authors as a starting point for improved riparian grazing management. Monitoring should then be conducted to determine if an adjustment is needed. In some situations, 7 cm or even less stubble height may provide for adequate riparian ecosystem function, particularly when streambanks are dry and stable or possibly at high elevations where vegetation is naturally of low stature. In other situations, 15-20 cm of stubble height may be required to reduce browsing of willows or limit trampling impact to vulnerable streambanks. The recommended criterion would apply to streamside and nearby meadow sites with hydrophilic or potentially hydrophilic vegetation, but not directly to dry meadows or even to all wet meadows. Stubble height may have little application where the streambanks are stabilized by coarse substrates, or the channels are deeply incised.The effects of residual stubble height in riparian functions have received limited direct experimental examination. Consequently, much of the information in this review was derived from studies indirectly related to the questions raised and, to some extent, from observations of experienced professionals. The authors have identified areas of scientific investigation needed to improve our understanding of the effects of stubble height on riparian function and grazing management.Key Words: Grazing, livestock management, streambanks, trampling, utilization, willowIn the early settlement history of the western United States management of riparian grazing lands was pretty straightforward-no irrigation or stock water to worry about-just turn the livestock out in the spring and take them home in the fall. We now know that proper management of these highly diverse ecosystems is not that easy. These land-water ecotones are among the most ecologically productive and diverse of all terrestrial habitats, and the influence of moving water within stream ripari- ResumenLa altura del rastrojo, una medida de la vegetación herb·cea remanente después de que ha sido sujeta apacentamiento, ha sido ampliamente utilizada en años recientes para medir el impacto del apacentamiento en las áeas ribereñas. La altura del rastrojo es una guáa de manejo a corto plazo que debe ser aplica...

Stocking Rate and Riparian Vegetation Effects on Physical Characteristics of Riparian Zones of Midwestern Pastures

“…m 21 stream during the approximately 60 d between measurements from May through November or the approximately 180 d between measurements in November and May or 6.52 cow-days ? m 21 stream annually would result in a sward height less than the 10 cm needed to protect against soil detachment during precipitation and treading events (Clary and Leininger 2000). Although the use of stubble height alone has been reported to be not suitable to predict sediment infiltration (Pearce et al 1997, Haan et al (2006) reported lower quantities and phosphorus loading of runoff from pastures that were rotationally stocked to a residual height of 10 cm than in pastures continuously stocked to a residual height of 5 cm in cool-season grass pastures.…”

“…Although the use of stubble height alone has been reported to be not suitable to predict sediment infiltration (Pearce et al 1997, Haan et al (2006) reported lower quantities and phosphorus loading of runoff from pastures that were rotationally stocked to a residual height of 10 cm than in pastures continuously stocked to a residual height of 5 cm in cool-season grass pastures. By maintaining adequate vegetation cover and height, plant vigor may be preserved (Frazier et al 1998;Clary and Leininger 2000) and reduce NPS pollution from riparian areas of pastures (Warren et al 1986;Elliott et al 2002;Reed and Carpenter 2002). In the current study, forage sward heights within riparian areas of pastures quadratically increased as the proportion of reed canarygrass increased y~4:06z0:40x{0:0027x 2 r 2~0 :42…”

“…Vegetation cover provides resistance to topsoil detachment by reducing raindrop forces (Hofman and Ries 1991;Pearce et al 1998) and may limit concentrated flow and runoff events (Self-Davis et al 2003;De Baets et al 2007). Furthermore, vegetation cover will entrap and retain sediment that is transported in precipitation runoff before it can enter streams (Clary et al 1996;Clary and Leininger 2000;Butler et al 2006).…”

Water Quality in the Agronomic Context: Flood Irrigation Impacts on Summer In-Stream Temperature Extremes in the Interior Pacific Northwest (USA)

“…Indirect effects of livestock on water quality include impacts to streamside plant communities and physical damage to streambanks. Riparian vegetation plays a critical role in sustaining the biotic integrity of the stream ecosystem by anchoring bank material in place during high flow events (Kleinfelder et al, 1992;Clary and Leininger, 2000). Livestock grazing of this resource is generally sustainable under conditions of moderate utilization (e.g., graze to 10cm stubble height; Boyd and Svejcar, 2004;Volesky et al, 2011), but timing of grazing can also influence livestock impacts on water quality and riparian vegetation (Boyd and Svejcar, 2004).…”

Grazing Management Effects on Sediment and Phosphorus in Surface Runoff

“…Maintaining optimum pasture cover and allowing litter to accumulate on the soil surface can preserve forage plant vigor, improve soil structure, stabilize sediment, and reduce the movement of nutrients from pastures into streams (Naeth et al 1991b(Naeth et al , 1996Clary and Leininger 2000). Rotational stocking systems and hay harvest have been shown to reduce the amount of bare ground and maintain an adequate forage canopy in pastures, as opposed to continuous stocking, so that excessive soil erosion and nutrient transport to surface waters are prevented (Gilley et al 1996;Manley et al 1997).…”