• Authors:
    • Kimble, J. M.
    • Follett, R. F.
  • Year: 2001
  • Summary: Grazing lands represent the largest and most diverse land resource-taking up over half the earth's land surface. The large area grazing land occupies, its diversity of climates and soils, and the potential to improve its use and productivity all contribute to its importance for sequestering C and mitigating the greenhouse effect and other conditions brought about by climate change. The Potential of U.S. Grazing Lands to Sequester Carbon and Mitigate the Greenhouse Effect gives you an in-depth look at this possibility.
  • Authors:
    • Lal, R.
    • Kimble, J. M.
    • Follett, R. F.
  • Year: 2001
  • Summary: Grazing lands represent the largest and most diverse land resource-taking up over half the earth's land surface. The large area grazing land occupies, its diversity of climates and soils, and the potential to improve its use and productivity all contribute to its importance for sequestering C and mitigating the greenhouse effect and other conditions brought about by climate change. The Potential of U.S. Grazing Lands to Sequester Carbon and Mitigate the Greenhouse Effect gives you an in-depth look at this possibility.
  • Authors:
    • Elliott, E. T.
    • Paustian, K.
    • Conant, R. T.
  • Source: Ecological Applications
  • Volume: 11
  • Issue: 2
  • Year: 2001
  • Summary: Grasslands are heavily relied upon for food and forage production. A key component for sustaining production in grassland ecosystems is the maintenance of soil organic matter (SOM), which can be strongly influenced by management. Many management techniques intended to increase forage production may potentially increase SOM, thus sequestering atmospheric carbon (C). Further, conversion from either cultivation or native vegetation into grassland could also sequester atmospheric carbon. We reviewed studies examining the influence of improved grassland management practices and conversion into grasslands on soil C worldwide to assess the potential for C sequestration. Results from 115 studies containing over 300 data points were analyzed. Management improvements included fertilization (39%), improved grazing management (24%), conversion from cultivation (15%) and native vegetation (15%), sowing of legumes (4%) and grasses (2%), earthworm introduction (1%), and irrigation (1%). Soil C content and concentration increased with improved management in 74% of the studies, and mean soil C increased with all types of improvement. Carbon sequestration rates were highest during the first 40 yr after treatments began and tended to be greatest in the top 10 cm of soil. Impacts were greater in woodland and grassland biomes than in forest, desert, rain forest, or shrubland biomes. Conversion from cultivation, the introduction of earthworms, and irrigation resulted in the largest increases. Rates of C sequestration by type of improvement ranged from 0.11 to 3.04 Mg C·ha-1 yr-1, with a mean of 0.54 Mg C·ha-1·yr-1, and were highly influenced by biome type and climate. We conclude that grasslands can act as a significant carbon sink with the implementation of improved management.
  • Authors:
    • Duarte, G. A.
    • Diaz-Zorita, M.
  • Source: Siembra Directa II
  • Year: 2001
  • Summary: Notes are given on the effects of incorporation of direct grazing in systems of continuous zero tillage in western Buenos Aires, Argentina. It is concluded that incorporation of grazing with direct sowing practices in mixed production systems is feasible, with the aim of maintaining high levels of stubble cover. The removal of crop residues reduces the potential for conservation of soil water and attenuates the impact of trampling by animals.
  • Authors:
    • Faour, K.
  • Source: Farm Budget Handbook, Southern NSW - Irrigated Winter Crops 2001
  • Year: 2001
  • Summary: This handbook presents gross margin budgets for irrigated winter crops and pasture establishment to assist landholders in the Murrumbidgee and Murray valleys (southern New South Wales, Australia) plan for the 2001 winter cropping season.
  • Authors:
    • Lal, R.
  • Source: The Potential of U.S. Grazing Lands to Sequester Carbon and Mitigate the Greenhouse Effect
  • Year: 2000
  • Authors:
    • Hart, R. H.
    • Reeder, J. D.
    • Schuman, G. E.
    • Morgan, J. A.
    • LeCain, D. R.
  • Source: Journal of Range Management
  • Volume: 53
  • Issue: 2
  • Year: 2000
  • Summary: The influence of cattle grazing on carbon cycling in the mixed grass prairie was investigated by measuring the CO2 exchange rate in pastures with a 13 year history of heavy or light grazing and an ungrazed exclosure at the High Plains Grasslands Research Station near Cheyenne, Wyo. In 1995, 1996 and 1997 a closed system chamber, which covered 1 m(2) of ground, was used every 3 weeks from April to October to measure midday CO2 exchange rate. Green vegetation index (similar to leaf area index), soil respiration rate, species composition, soil mater content, soil temperature, and air temperature were also measured to relate to CO2 exchange rates of the 3 grazing treatments. Treatment differences varied among gears, but overall early season (mid April to mid June) CO2 exchange rates in the grazed pastures were higher (up to 2.5 X) than in the exclosure. Higher early season CO2 exchange rates were associated with earlier spring green-up in grazed pastures, measured as higher green vegetation index. As the growing season progressed, green vegetation index increased in all pastures, but more so in the ungrazed exclosure, resulting in occasionally higher (up to 2 X) CO2 exchange rate compared with grazed pastures late in the season. Seasonal treatment differences mere not associated with soil temperature, soil respiration rate, or air temperature, nor was there a substantial change in species composition due to grazing. We hypothesize that early spring green-up and higher early season CO2 exchange rate in grazed pastures may be due to better light penetration and a warmer microclimate near the soil surface because of less litter and standing dead compared to the ungrazed pastures. When all the measurements mere averaged over the entire season, there mas no difference in CO2 exchange rate between heavily grazed, lightly prated and ungrazed pastures in this ecosystem.
  • Authors:
    • Wilkinson, S. R.
    • Schomberg, H. H.
    • Stuedemann, J. A.
    • Franzluebbers, A. J.
  • Source: Soil Biology and Biochemistry
  • Volume: 32
  • Issue: 4
  • Year: 2000
  • Summary: Soil organic matter pools under contrasting long-term management systems provide insight into potentials for sequestering oil C, sustaining soil fertility and functioning of the soil±atmospheric interface. We compared soil C and N pools (total, articulate and microbial) under pastures (1) varying due to harvest technique (grazing or haying), species composition (cool- or arm-season), stand age and previous land use and (2) in comparison with other land uses. Grazed tall fescue-common ermudagrass pasture (20 yr old) had greater soil organic C (31%), total N (34%), particulate organic C (66%), articulate organic N (2.4 fold) and soil microbial biomass C (28%) at a depth of 0±200 mm than adjacent land in conservation-tillage cropland (24 yr old). Soil organic C and total N at a depth of 0±200 mm averaged 3800 and 294 g m-2 , respectively, under grazed bermudagrass and 3112 and 219 g m-2, respectively, under hayed bermudagrass. A chronosequence of grazed tall fescue suggested soil organic N sequestration rates of 7.3, 4.4 and 0.6 g m-2 yr-1 to a depth of 200 mm during 0±10, 10±30 and 30±50 yr, respectively. Soil C storage under long-term grazed tall fescue was 85 to 88% of that under forest, whereas soil N storage was 77 to 90% greater under grazed tall fescue than under forest. Properly grazed pastures in the Southern Piedmont USA have great potential to restore natural soil fertility, sequester soil organic C and N and increase soil biological activity.
  • Authors:
    • Manley, W. A.
    • Hart, R. H.
    • Manley, J. T.
    • Reeder, J. D.
    • Schuman, G. E.
  • Source: Ecological Applications
  • Volume: 9
  • Issue: 1
  • Year: 1999
  • Summary: Rangeland grazing management strategies have been developed in an effort to sustain efficient use of forage resources by livestock. However, the effects of grazing on the redistribution and cycling of carbon (C) and nitrogen (N) within the plant-soil system are not well understood. We examined the plant-soil C and N balances of a mixed grass rangeland under three livestock stocking rates using an area that had not been grazed by domestic livestock for more than 40 years. We established nongrazed exclosures and pastures subjected to continuous season-long grazing at either a light stocking rate (20 steer-days/ha) or a heavy stocking rate (59 steer-days/ha, ~50% utilization of annual production). Twelve years of grazing under these stocking rates did not change the total masses of C and N in the plant-soil (0-60 cm) system but did change the distribution of C and N among the system components, primarily via a significant increase in the masses of C and N in the root zone (0-30 cm) of the soil profile. The mass of soil C (0-60 cm) under heavy grazing was comparable to that of the light grazing treatment. Grazing at the heavy stocking rate resulted in a decrease in peak standing crop (PSC) of aboveground live phytomass, an increase in blue grama (Bouteloua gracilis [H.B.K.] Lag. Ex Steud.), and a decrease in western wheatgrass (Pascopyrum smithii [Rydb.] A. Love) compared to the light grazing treatment. The dominant species under light grazing was western wheatgrass, whereas in the nongrazed exclosures, forbs were dominant and appeared to have increased at the expense of western wheatgrass. The observed increase of soil C and N in the surface soil where roots dominate indicates a greater opportunity for nutrient availability and cycling, and hence enhanced grazing quality.
  • Authors:
    • Manley, J. T.
    • Waggoner, J. W.,Jr.
    • Smith, M. A.
    • Samuel, M. J.
    • Hart, R. H.
    • Manley, W. A.
  • Source: Journal of Range Management
  • Volume: 50
  • Issue: 6
  • Year: 1997
  • Summary: Rotation grazing strategies have been proposed to increase stocking capacity, improve animal gains, and improve forage production and range condition. We compared continuous or season-long, 4-pasture rotationally deferred, and 8-paddock time-controlled rotation grazing on mixed-grass rangeland near Cheyenne, Wyo. from 1982 through 1994. Stocking rates under light, moderate and heavy grazing averaged 21.6, 47.0, and 62.7 steer-day ha(-1); grazing pressures were 11.0 to 90.1 steer-day Mg-1 of forage dry matter produced. We estimated above-and below-ground biomass, botanical composition and basal cover. Bare ground and cover of warm-season grasses, forbs, and lichens were greater under heavy stocking; cover of litter, western wheatgrass, and total cool-season graminoids were greater under light stocking. Stocking rate and grazing strategy had no effect on above-ground biomass and little effect on below-ground biomass. Under heavy stocking, percent of above-ground biomass contributed by forbs increased, especially under time-controlled rotation grazing, and that of western wheatgrass decreased. Otherwise, effects of grazing strategy, level vs. slope, and north vs. south slope on vegetation were insignificant. Steer average daily gain decreased linearly as grazing pressure increased (r(2) = 0.44); grazing strategies had no significant effect. When cattle prices are favorable, the stocking rates that are most profitable in the short run may be high enough to reduce range condition.