Photo: Longhorns, Central Texas. Copyright 2017 Delena Norris-Tull
The World Economic Forum developed a report, Transforming Food Systems with Farmers, to assist the European Union nations in developing sustainable agricultural practices, practices the WEF calls Climate-Smart Agriculture. The report (p.35-38) describes the advantages of managed grazing, which it defines as, "Using practices that sequester carbon in grassland soils by adjusting livestock stocking rates, timing and intensity of grazing." Download the full report and recommendations at https://www.weforum.org/reports/transforming-food-systems-with-farmers-a-pathway-for-the-eu
Training livestock to eat noxious weeds
Kathy Voth conducted research that enabled her to develop a technique to train cattle to eat noxious weeds. Details are available on her website: https://livestockforlandscapes.com/cowmanagers.htm. She lists which noxious weeds have high nutritional value for cattle, and shows the training process.
Cattle and sheep grazing with herbicide
Pywell, et al., 2010, conducted two fields experiments lasting six years, to compare the effectiveness of various grazing treatments, used to control Canada/creeping thistle, in semi-improved grasslands in the UK. Of the two sites, one site, Bucks, “represented typical extensive mixed cattle and sheep systems in lowland central England.” This site was species-poor. the other site, Powys, “had more species and represented typical extensive sheep systems in the uplands of Wales.”
At Bucks, four grazing treatments were used that were factorial combinations of the following: tight versus lenient spring cattle grazing; tight versus lenient autumn sheep grazing; and a fifth treatment: winter sheep grazing added to spring tight cattle and autumn lenient summer cattle grazing. All grazing treatments included lenient summer cattle grazing.
At Powys, four grazing treatments were used that were factorial combinations of the following: tight versus lenient spring sheep grazing; tight versus lenient autumn sheep grazing. Fifth treatment: winter sheep grazing added to spring tight and autumn lenient sheep grazing. Sixth treatment: tight spring cattle grazing followed by tight autumn sheep grazing. All grazing regimes included lenient summer sheep grazing.
In both sites, the control was lenient grazing in spring, summer and autumn, as this was similar to grazing methods recommended in these farming regions.
Herbicide and mechanical removal sub-treatments were included within each grazing treatment. “Mechanical thistle control was by cutting in June and again in September using a tractor-mounted flail mower with the cut material left in situ. Herbicide control was tested by applying the selective compound clopyralid in June using a trailed weed wiper…Sub-treatment (E) combined June cutting and September herbicide application… Sub-treatment (F)… investigated the traditional regional practice of rotational hay cutting 1 year in.”
“In winter 2000, these plots were enclosed and hay was cut and removed in June 2001. All the other weed control sub-treatments were applied in 2000 and 2001.” The sub-treatments were not repeated in subsequent years.
Pywell, et al., 2010, results:
Analysis 1: Seasonal grazing intensity and weed control measures:
At Bucks:
Analysis 2: Winter grazing:
Analysis 3: Grazing animal: At Powys, by 2003, tight autumn cattle grazing decreased thistle abundance compared to tight autumn sheep grazing.
Effects of weed control sub-treatments results (Pywell, et al., 2010):
Analysis 1:
At Bucks: Rapid decrease in control effects on thistle abundance after 2001, with no effects by 2005. In the short term, herbicide wiping was always more effective than cutting alone, cutting plus herbicide wiping, or rotational haying (which was only slightly better than the control).
At Powys there was a more gradual decline in control effects on thistle abundance after 2001, but by 2004, no weed control effects remained. In the short term, herbicide wiping was always the most effective control. But cutting plus herbicide was more effective than cutting alone. Cutting was only slightly better than the control.
Pywell, et al., 2010, “At both sites the overall decline in mean thistle number over time across all sub-treatments is simply a reflection of the declines caused by the lenient grazing treatments.”
Pywell, et al., 2010, conclusions: “The most rapid and effective way of controlling thistles in the lowland sheep and cattle system in Bucks was herbicide wiping in June together with lenient spring cattle grazing and lenient autumn sheep grazing… The most effective means of controlling thistles in the upland sheep system in Powys was once again herbicide wiping, but in this case, combined with lenient spring sheep grazing.”
“There were no significant effects of grazing or weed control on species richness of non-target forbs in Bucks…, which probably reflected the low number of species. In contrast, grazing had a number of significant impacts on forb richness at Powys... Lenient spring grazing reduced richness..., but this effect did not develop until the sixth year. Tight autumn grazing by sheep had a more rapid and consistently beneficial effect on forb richness compared with tight cattle grazing... Finally, herbicide application in June using a weed wiper had a small, but long-term negative effect on forb numbers which extended into 2005,” Pywell, et al., 2010.
“The effects of herbicide fade rapidly once application ceases and the lack of grazing x weed control interactions suggests that lenient grazing alone will give equally effective control in the longer term. Moreover, given the temporary effect of [herbicide] wiping on thistles and the evidence of damage to non-target species, it may be better to avoid weed-wiping at more diverse sites and manage thistles purely by grazing,” Pywell, et al., 2010.
Cattle grazing with herbicide and seeding
Taylor, et al., 2013, compared various combinations of grazing, herbicides, and seeding to determine their usefulness in facilitating restoration of abandoned agricultural fields in the Pacific Northwest. They conducted the study in a relict bunchgrass prairie, the Zumwalt Prairie in northeastern Oregon. About 10% of the prairie is composed of abandoned fields that are heavily infested with exotic perennial grasses that were planted decades ago as livestock forage. Previous studies have found that exotic species in abandoned fields can persist for decades. The old fields within this prairie are low in native species richness and lack biological soil crusts. The small size of the fields (<100 ha) and their proximity to intact native prairie species, and “intact hydrologic function” make them good candidates for restoration.
Taylor, et al., 2013, tested grazing treatments in 200m X 100m plots, using either “summer grazing at 80% utilization using cow-calf pairs for three consecutive years (2004—2006), or non-grazed.” The following seeding and herbicide treatment combinations were tested in 50m X 50m plots within the grazed plots: grazing, grazing+herbicide, grazing+herbicide+seeding, grazing+seeding, herbicide, herbicide+seeding, seeding, and a non-treated control.” After grazing, glyphosate was applied in July 2006. “Five species of locally-sourced native perennial grasses were seeded” beginning in November 2006, but due to poor weather, seeding was completed in April 2007.
In June 2004 and again in June 2008, density by species was measured.
Taylor, et al., 2013, results: “Treatments did not consistently affect exotic perennial grass functional group density. However, our analysis of individual species found that intermediate wheatgrass, timothy, and exotic Poa species densities were significantly reduced by the application of herbicide… Exotic Festuca species density increased in plots that were sprayed but not seeded…, while combining herbicide with seeding resulted in declines of the exotic Festuca species… In contrast, intermediate wheatgrass decreased in herbicide plots.”
“The native perennial grass functional group density increased from a mean of 8 ± 6 culms/m2 to 161 ± 53 culms/m2 from 2004 to 2008 when seeding and grazing were combined... Finally, herbicide combined with grazing enhanced establishment of all seeded native perennial grass species, with 65% of frames in the seed+graze+herbicide plots having native perennial grass seedlings compared to < 2% of frames having native perennial grass seedlings in the seed+herbicide plots.”
Taylor, et al., 2013, found that individual native species and exotic species responded differently to the treatments. “Seeding increased bluebunch wheatgrass density… Bluebunch wheatgrass density in herbicide and seeding plots… was greater than that of non-sprayed seeded plots… In addition, plots grazed prior to seeding experienced a greater increase in bluebunch wheatgrass than those that were not grazed.” Wheatgrass density also increased in plots with both herbicide and grazing.
Taylor, et al., 2013, found that, “Though herbicide alone did not affect Idaho fescue, plots also receiving the seeding treatment experienced a significant density increase…while those sprayed but not seeded resulted in lower average density…. Grazing increased the density of Idaho fescue in non-sprayed plots independent of seeding treatment. Seeding increased Idaho fescue density but only in plots where herbicide was applied. Similar effects were also observed with respect to Idaho fescue establishment; seeded plots that had been treated with herbicide had an average of 65% of frames containing Idaho fescue seedlings compared to 30% for seeded, non-sprayed plots.”
“Increases in total native perennial grasses and in bluebunch wheatgrass individually were greater when grazing preceded seeding.”
“Although glyphosate reduced the abundance of several exotic perennial grasses…, the effect was small. Timing the application at the end of the growing season when most natives are senescing and less vulnerable to herbicide may minimize future negative impacts to desired native species. Future research examining the effect of timing and rates of glyphosate (and other herbicides) and how these factors affect native and exotic grass species should increase the effectiveness of this tool.”
Taylor, et al., 2013, concluded, “Evidence that cattle favor exotic over native perennial grasses in this ecosystem reveals a potential, low-cost tool for influencing species composition of old fields….Although grazing increased several native bunch grass species, the effects were small and dependent on seeding and/or herbicide treatments. The relatively subtle effect of grazing is likely related to difficulties in obtaining consistent and adequate utilization. Both topography and location of water in the pasture resulted in uneven distribution of cattle…. Our research demonstrates that simple, low-cost interventions can increase native perennial grasses at the expense of exotic perennial grasses.”
High-impact cattle grazing compared to no grazing
Loeser, et al., 2007, conducted an 8-year study of high-impact cattle grazing, compared with no grazing and moderate grazing (which was the control). The study was conducted in a high-altitude semi-arid grassland near Flagstaff, Arizona. They found that high-impact cattle grazing enabled invasive annual species, particularly cheatgrass, to dominate over perennial native forbs. They found that the removal of cattle from the area (no grazing) lead to only slight increases in native forbs and also led to reduced species richness. The moderate grazing control had improved native plant diversity, compared to high-impact grazing or no grazing. A severe drought in year six led to higher exotic species invasion, especially in the high-impact grazing plots.
Loeser, et al., 2007, concluded that, “Surprisingly, cattle removal and high-impact grazing treatments, which were designed to represent opposing ends of a grazing intensity gradient, produced similar ecological outcomes. Both treatments reduced native species richness and increased exotic species richness in comparison with the moderate-intensity treatment. It may be that an intermediate level of disturbance from livestock grazing can promote a more heterogeneous landscape, providing greater opportunity for a variety of plants.”
References:
Next Sections on Grazing Solutions:
Links to additional Innovative Solutions:
The World Economic Forum developed a report, Transforming Food Systems with Farmers, to assist the European Union nations in developing sustainable agricultural practices, practices the WEF calls Climate-Smart Agriculture. The report (p.35-38) describes the advantages of managed grazing, which it defines as, "Using practices that sequester carbon in grassland soils by adjusting livestock stocking rates, timing and intensity of grazing." Download the full report and recommendations at https://www.weforum.org/reports/transforming-food-systems-with-farmers-a-pathway-for-the-eu
Training livestock to eat noxious weeds
Kathy Voth conducted research that enabled her to develop a technique to train cattle to eat noxious weeds. Details are available on her website: https://livestockforlandscapes.com/cowmanagers.htm. She lists which noxious weeds have high nutritional value for cattle, and shows the training process.
Cattle and sheep grazing with herbicide
Pywell, et al., 2010, conducted two fields experiments lasting six years, to compare the effectiveness of various grazing treatments, used to control Canada/creeping thistle, in semi-improved grasslands in the UK. Of the two sites, one site, Bucks, “represented typical extensive mixed cattle and sheep systems in lowland central England.” This site was species-poor. the other site, Powys, “had more species and represented typical extensive sheep systems in the uplands of Wales.”
At Bucks, four grazing treatments were used that were factorial combinations of the following: tight versus lenient spring cattle grazing; tight versus lenient autumn sheep grazing; and a fifth treatment: winter sheep grazing added to spring tight cattle and autumn lenient summer cattle grazing. All grazing treatments included lenient summer cattle grazing.
At Powys, four grazing treatments were used that were factorial combinations of the following: tight versus lenient spring sheep grazing; tight versus lenient autumn sheep grazing. Fifth treatment: winter sheep grazing added to spring tight and autumn lenient sheep grazing. Sixth treatment: tight spring cattle grazing followed by tight autumn sheep grazing. All grazing regimes included lenient summer sheep grazing.
In both sites, the control was lenient grazing in spring, summer and autumn, as this was similar to grazing methods recommended in these farming regions.
Herbicide and mechanical removal sub-treatments were included within each grazing treatment. “Mechanical thistle control was by cutting in June and again in September using a tractor-mounted flail mower with the cut material left in situ. Herbicide control was tested by applying the selective compound clopyralid in June using a trailed weed wiper…Sub-treatment (E) combined June cutting and September herbicide application… Sub-treatment (F)… investigated the traditional regional practice of rotational hay cutting 1 year in.”
“In winter 2000, these plots were enclosed and hay was cut and removed in June 2001. All the other weed control sub-treatments were applied in 2000 and 2001.” The sub-treatments were not repeated in subsequent years.
Pywell, et al., 2010, results:
Analysis 1: Seasonal grazing intensity and weed control measures:
At Bucks:
- Lenient grazing in both seasons reduced thistle abundance from autumn 2003-spring 2004 and onwards.
- Tight grazing in both seasons maintained thistle abundance at high levels.
- From 2000-2005, “lenient spring and autumn grazing alone reduced thistle abundance” when compared with the high density control plots. Lenient spring grazing prevented an increase in thistle populations in the low density plots compared with tight grazing over the six year period.
- Only lenient grazing in spring reduced thistle abundance from 2003 onwards.
- Tight spring grazing maintained thistle abundance at high levels.
- Autumn grazing had no significant effect.
- There were no synergistic effects of combining spring and autumn grazing.
Analysis 2: Winter grazing:
- At Bucks, winter grazing maintained thistle abundance at high levels, which effect increased each year.
- At Powys, winter grazing maintained thistle abundance at high levels, but took longer, as the effect was apparent by 2005.
Analysis 3: Grazing animal: At Powys, by 2003, tight autumn cattle grazing decreased thistle abundance compared to tight autumn sheep grazing.
Effects of weed control sub-treatments results (Pywell, et al., 2010):
Analysis 1:
At Bucks: Rapid decrease in control effects on thistle abundance after 2001, with no effects by 2005. In the short term, herbicide wiping was always more effective than cutting alone, cutting plus herbicide wiping, or rotational haying (which was only slightly better than the control).
At Powys there was a more gradual decline in control effects on thistle abundance after 2001, but by 2004, no weed control effects remained. In the short term, herbicide wiping was always the most effective control. But cutting plus herbicide was more effective than cutting alone. Cutting was only slightly better than the control.
Pywell, et al., 2010, “At both sites the overall decline in mean thistle number over time across all sub-treatments is simply a reflection of the declines caused by the lenient grazing treatments.”
Pywell, et al., 2010, conclusions: “The most rapid and effective way of controlling thistles in the lowland sheep and cattle system in Bucks was herbicide wiping in June together with lenient spring cattle grazing and lenient autumn sheep grazing… The most effective means of controlling thistles in the upland sheep system in Powys was once again herbicide wiping, but in this case, combined with lenient spring sheep grazing.”
“There were no significant effects of grazing or weed control on species richness of non-target forbs in Bucks…, which probably reflected the low number of species. In contrast, grazing had a number of significant impacts on forb richness at Powys... Lenient spring grazing reduced richness..., but this effect did not develop until the sixth year. Tight autumn grazing by sheep had a more rapid and consistently beneficial effect on forb richness compared with tight cattle grazing... Finally, herbicide application in June using a weed wiper had a small, but long-term negative effect on forb numbers which extended into 2005,” Pywell, et al., 2010.
“The effects of herbicide fade rapidly once application ceases and the lack of grazing x weed control interactions suggests that lenient grazing alone will give equally effective control in the longer term. Moreover, given the temporary effect of [herbicide] wiping on thistles and the evidence of damage to non-target species, it may be better to avoid weed-wiping at more diverse sites and manage thistles purely by grazing,” Pywell, et al., 2010.
Cattle grazing with herbicide and seeding
Taylor, et al., 2013, compared various combinations of grazing, herbicides, and seeding to determine their usefulness in facilitating restoration of abandoned agricultural fields in the Pacific Northwest. They conducted the study in a relict bunchgrass prairie, the Zumwalt Prairie in northeastern Oregon. About 10% of the prairie is composed of abandoned fields that are heavily infested with exotic perennial grasses that were planted decades ago as livestock forage. Previous studies have found that exotic species in abandoned fields can persist for decades. The old fields within this prairie are low in native species richness and lack biological soil crusts. The small size of the fields (<100 ha) and their proximity to intact native prairie species, and “intact hydrologic function” make them good candidates for restoration.
Taylor, et al., 2013, tested grazing treatments in 200m X 100m plots, using either “summer grazing at 80% utilization using cow-calf pairs for three consecutive years (2004—2006), or non-grazed.” The following seeding and herbicide treatment combinations were tested in 50m X 50m plots within the grazed plots: grazing, grazing+herbicide, grazing+herbicide+seeding, grazing+seeding, herbicide, herbicide+seeding, seeding, and a non-treated control.” After grazing, glyphosate was applied in July 2006. “Five species of locally-sourced native perennial grasses were seeded” beginning in November 2006, but due to poor weather, seeding was completed in April 2007.
In June 2004 and again in June 2008, density by species was measured.
Taylor, et al., 2013, results: “Treatments did not consistently affect exotic perennial grass functional group density. However, our analysis of individual species found that intermediate wheatgrass, timothy, and exotic Poa species densities were significantly reduced by the application of herbicide… Exotic Festuca species density increased in plots that were sprayed but not seeded…, while combining herbicide with seeding resulted in declines of the exotic Festuca species… In contrast, intermediate wheatgrass decreased in herbicide plots.”
“The native perennial grass functional group density increased from a mean of 8 ± 6 culms/m2 to 161 ± 53 culms/m2 from 2004 to 2008 when seeding and grazing were combined... Finally, herbicide combined with grazing enhanced establishment of all seeded native perennial grass species, with 65% of frames in the seed+graze+herbicide plots having native perennial grass seedlings compared to < 2% of frames having native perennial grass seedlings in the seed+herbicide plots.”
Taylor, et al., 2013, found that individual native species and exotic species responded differently to the treatments. “Seeding increased bluebunch wheatgrass density… Bluebunch wheatgrass density in herbicide and seeding plots… was greater than that of non-sprayed seeded plots… In addition, plots grazed prior to seeding experienced a greater increase in bluebunch wheatgrass than those that were not grazed.” Wheatgrass density also increased in plots with both herbicide and grazing.
Taylor, et al., 2013, found that, “Though herbicide alone did not affect Idaho fescue, plots also receiving the seeding treatment experienced a significant density increase…while those sprayed but not seeded resulted in lower average density…. Grazing increased the density of Idaho fescue in non-sprayed plots independent of seeding treatment. Seeding increased Idaho fescue density but only in plots where herbicide was applied. Similar effects were also observed with respect to Idaho fescue establishment; seeded plots that had been treated with herbicide had an average of 65% of frames containing Idaho fescue seedlings compared to 30% for seeded, non-sprayed plots.”
“Increases in total native perennial grasses and in bluebunch wheatgrass individually were greater when grazing preceded seeding.”
“Although glyphosate reduced the abundance of several exotic perennial grasses…, the effect was small. Timing the application at the end of the growing season when most natives are senescing and less vulnerable to herbicide may minimize future negative impacts to desired native species. Future research examining the effect of timing and rates of glyphosate (and other herbicides) and how these factors affect native and exotic grass species should increase the effectiveness of this tool.”
Taylor, et al., 2013, concluded, “Evidence that cattle favor exotic over native perennial grasses in this ecosystem reveals a potential, low-cost tool for influencing species composition of old fields….Although grazing increased several native bunch grass species, the effects were small and dependent on seeding and/or herbicide treatments. The relatively subtle effect of grazing is likely related to difficulties in obtaining consistent and adequate utilization. Both topography and location of water in the pasture resulted in uneven distribution of cattle…. Our research demonstrates that simple, low-cost interventions can increase native perennial grasses at the expense of exotic perennial grasses.”
High-impact cattle grazing compared to no grazing
Loeser, et al., 2007, conducted an 8-year study of high-impact cattle grazing, compared with no grazing and moderate grazing (which was the control). The study was conducted in a high-altitude semi-arid grassland near Flagstaff, Arizona. They found that high-impact cattle grazing enabled invasive annual species, particularly cheatgrass, to dominate over perennial native forbs. They found that the removal of cattle from the area (no grazing) lead to only slight increases in native forbs and also led to reduced species richness. The moderate grazing control had improved native plant diversity, compared to high-impact grazing or no grazing. A severe drought in year six led to higher exotic species invasion, especially in the high-impact grazing plots.
Loeser, et al., 2007, concluded that, “Surprisingly, cattle removal and high-impact grazing treatments, which were designed to represent opposing ends of a grazing intensity gradient, produced similar ecological outcomes. Both treatments reduced native species richness and increased exotic species richness in comparison with the moderate-intensity treatment. It may be that an intermediate level of disturbance from livestock grazing can promote a more heterogeneous landscape, providing greater opportunity for a variety of plants.”
References:
- Loeser, M.R.R., Sisk, T.D., & Crews, T.E. (Feb., 2007). Impact of grazing intensity during drought in an Arizona grassland. Conservation Biology, 21 (1): 87-97.
- Pywell, R.F., et al. (2010). Minimizing environmental impacts of grassland weed management: Can Cirsium arvense be controlled without herbicides? Grass and Forage Science, 65: 159-174.
- Taylor, R.V., Pokorny, M.L., Mangold, J., & Rudd, N. (June, 2013). Can a combination of grazing, herbicides, and seeding facilitate succession in old fields? Ecological Restoration, 31(2): 141-143.
- World Economic Forum. (April 2022). Transforming Food Systems with Farmers: A Pathway for the EU. World Economic Forum, in collaboration with Deloitte & NTT Data.
https://www.weforum.org/reports/transforming-food-systems-with-farmers-a-pathway-for-the-eu
Next Sections on Grazing Solutions:
Links to additional Innovative Solutions: