Progress 10/01/03 to 09/30/09
Outputs
OUTPUTS: Prepared pastures for grazing, e.g. fixed fence, put out fence chargers and solar panels, moved and staked down utilization cages, placed salt and mineral blocks, filled water troughs, advertised for and hired summer crew, trained crew in radiation safety and plant identification, maintained neutron probes, sampled and analyzed soil water, collected precipitation data, sampled frequency, density and basal cover data and analyzed data, sampled forage production and utilization and analyzed data, checked on cattle and maintained the proper number in each pasture, checked use on pastures, weighted cattle, collected price information on cattle, brought in solar panels and fence charges and drained water tanks at the end of the grazing season, prepared annual report for distribution to the public. Results from this research have been distributed in refereed journals, at professional conferences, graduate students have studied aspects of this project and written thesis and dissertations, published in our annual report, shared with a local high school science class and we have filled data and publication requests. PARTICIPANTS: Patton, B.D., principal investigator Nyren, P.E., Research Center Director Dong, X., sampled soil water, forage production and utilization, also principal investigator on an ecosystem modeling study using this project Nyren, A.C., data analysis Schmidt, D.E., handle and weigh cattle Mantz, G., handle, weigh and condition score cattle Bohn, R., sampled soil water, forage production and utilization, frequency and density of plant species Eklund, B., sampled soil water, forage production and utilization, frequency and density of plant species, checked cattle, received training in radiation safety, plant species identification and vegetation sampling techniques Trinidad, H., sampled soil water, forage production and utilization, frequency and density of plant species, checked cattle, received training in radiation safety, plant species identification and vegetation sampling techniques Slaughter, K., sampled forage production and utilization, frequency and density of plant species, checked cattle, received training in plant species identification and vegetation sampling techniques Patton, J.E., sampled forage production and utilization, frequency and density of plant species, edited reports, received training in plant species identification and vegetation sampling techniques Dewald, S., helped with data entry Schlecht, C. helped with data entry Wang, G., Ph.D. student studying grazing management effects on plant community and soil hydrology and their relationship in the Missouri Coteau region is utilizing this project for study sites TARGET AUDIENCES: The primary target audience is the local livestock producer. This audience was reached though publication of an article in our annual report and a more detailed report published on our research centers web site, discussion of our findings at our annual Research Roundup and a short article on managing Kentucky bluegrass invasion in the Midwest Forage Association, Forage Focus. The secondary audience is the scientific community this audience was reached with a poster on plant root biomass and respiration presented at the Joint Meeting of the Society for Range Management and the American Forage and Grassland Council in Louisville, KY., a presentation on the effects of grazing and drought on photosynthesis and respiration presented at the International Grassland Congress in Hohhot, China, an article published in Acta Prataculturae Sinica on the effect of stocking rate on multiple management objectives and a presentation on the effect of annual, growing season, and spring precipitation on peak standing crop presented at the Annual Meeting of the Society for Range Management in Albuquerque, New Mexico. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The average peak forage production on silty range sites from 1992 to 2009 was 2698, 3102, 2877, 2381, and 2131 lbs/acre on the ungrazed, light, moderate, heavy, and extreme grazing intensity treatments, respectively. The average peak forage production on overflow range sites from 1993 to 2009 under the same treatments was 3329, 4091, 4095, 3895, and 2592 lbs/acre. For both types of range sites, the extreme grazing treatment produced the least forage. The light treatment is the most productive on silty range sites. On overflow range sites, the light, moderate, and heavy treatments show little difference, but moderate grazing treatment tends to be the most productive. A total of 161 species have been found on the silty range sites and 61 have shown a response to grazing based on frequency, density, or basal cover. Of the 172 species on the overflow range sites, 53 have responded to grazing. These responses include increasing or decreasing with increased grazing pressure, benefiting from moderate grazing, or invading (only appearing after heavy grazing). Of the species responding to grazing (30-40% of the total), the majority are favored by a moderate or heavy level of grazing. Since 1990, average daily gain and animal body condition scores have decreased with increasing grazing intensity. From 1991 to 2009, the average daily gain has been 1.39, 1.28, 1.10, and 0.79 lbs/head /day on the light, moderate, heavy, and extreme treatments, respectively. The corresponding average gain/acre each year over this same period has been 29.42, 54.47, 76.03, and 80.20 lbs/acre, and average body condition scores from 1994 to 2009 were 5.49, 5.37, 5.24 and 4.92 respectively. These averages vary greatly from year to year due to variation in forage, weather, cattle weights and their potential to gain. Initially, gain/acre increases as the stocking rate increases, but there comes a point when gains/acre decline. We cannot predict which stocking rate will give the maximum gain/acre in a particular year. However, at 2.11 AUM/acre, gain/acre from 1991-2009 would have averaged 75.5 lbs/acre, with a range of -39.3 lbs/acre in 2002 to 147.3 lbs/acre in 1993. Average gain/acre at the average moderate stocking rate, 1.09 AUM/acre, from 1991-2009 would have been 56.6 lbs/acre. If cattle prices were constant, then return/acre would peak at a stocking rate somewhere below maximum gain/acre, with the exact point depending on carrying costs. The change in cattle prices over the season determines the stocking rate with the maximum return/acre. The stocking rate with the maximum return/acre over the last 19 years would be 2.00 AUM/acre, with an average annual return of $34.81. Under the moderate stocking rate of 1.09 AUM/acre the average annual return would have been $27.08. The Natural Resources Conservation Service has used information obtained from this study in developing ecological site descriptions and state and transition models. Graduate students have been able to use the pastures in this study as treatments in their research. Students hired for data collection have learned skills that they can apply in their chosen profession.
Publications
- Dong, X.J., J.Z. Wang, G.J. Wang, D.J. Wang, J.H. Wang, X.Y. Zhao, B.D. Patton, S.P. Wang and P.E. Nyren. 2008. Does grazing affect rangeland roots A hypothesis testing with small samples. 2008 Joint Meeting of the Society for Range Management and the American Forage and Grassland Council, Louisville, KY, 26-31 Jan. 2008.
- Dong, X.J., P.E. Nyren, B.D. Patton, G.J. Wang, B.S. Kreft, A.C. Nyren, R. Limb, D. Kirby and L. Cihacek. 2008. Photosynthesis and soil respiration from a mixed-grass prairie: Effects of cattle grazing and drought. Proceedings of the 2008 Joint Conference of the XXI International Grassland Congress and the VIII International Rangeland Congress. Hohhot, China, June 29 to July 5th, 2008. Multifunctional Grasslands in a Changing World. Volume I. Page 177. Edited by Organizing Committee of 2008 IGC/IRC Conference. Guangdong People's Publishing House. Guangzhou, China.
- Pan, X., J.H. Wang, S.P. Wang, P.E. Nyren, B.D. Patton, X.J. Dong, A.C. Nyren. 2008. Studies on optimum grazing rates in grasslands based on a multi-objectives weighting analysis. Acta Prataculturae Sinica 17(4):149-58.
- Patton, B.D., P.E. Nyren, G. Mantz and A.C. Nyren. 2009. Long-Term Grazing Intensity Research in the Missouri Coteau of North Dakota. North Dakota State University Central Grasslands Research Extension Center 2008 Grass and Beef Research Review, Streeter, North Dakota, North Dakota State University - Central Grasslands Research Extension Center. P. 7.
- Dunn, G., L. J. Wiles, J. Printz, B.D. Patton, A.C. Nyren. 2009. Effect of annual, growing season, and spring precipitation on peak standing crop at three locations. 62nd Annual Meeting of the Society for Range Management, Albuquerque, New Mexico. February 8-13, 2009.
- Dong, X., B.D. Patton and P.E. Nyren. 2009. North Dakota - Managing Kentucky Bluegrass Invasion in Native Prairies. Midwest Forage Association Forage Focus. August 2009. P. 21.
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: Prepared pastures for grazing, e.g. fixed fence, put out fence chargers and solar panels, moved and staked down utilization cages, placed salt and mineral blocks, filled water troughs, advertised for and hired summer crew, trained crew in radiation safety and plant identification, maintained neutron probes, sampled and analysed soil water, collected precipitation data, sampled frequency, density and basal cover data and analysed data, sampled forage production and utilization and analyzed data, checked on cattle and maintained the proper number in each pasture, checked use on pastures, weighted cattle, collected price information on cattle, brought in solar panels and fence charges and drained water tanks at the end of the grazing season, prepared annual report for distribution to the public, spoke at the "Plant Community Thresholds and Triggers on the Northern Great Plains Workshop" on the changes in the plant communities on the grazing intensity trial, spoke at the Range Forum in Mandan on the changes we have seen on the grazing intensity trial, worked on article on the effect of species diversity on stability, spoke to the public at Research Roundup on findings from the grazing intensity research study, presented poster on root production and respiration and resampling at Society for Range Management meeting in Louisville, Kentucky, worked on an article on the effect of annual, growing season, and spring precipitation on peak standing crop, filled data and publication requests. PARTICIPANTS: Patton, B.D., principal investigator Nyren, P.E., Research Center Director Dong, X., sampled soil water, forage production and utilization, also principal investigator on an ecosystem modeling study using this project Nyren, A.C., data analysis Schmidt, D.E., handle and weigh cattle Mantz, G., handle, weigh and condition score cattle Bohn, R., sampled soil water, forage production and utilization, frequency and density of plant species Wyatt, C., sampled soil water, forage production and utilization, frequency, density and basal cover of plant species, checked cattle, received training in radiation safety, plant species identification and vegetation sampling techniques Knodel, B., sampled soil water, forage production and utilization, frequency, density and basal cover of plant species, checked cattle, received training in radiation safety, plant species identification and vegetation sampling techniques Slaughter, K., sampled soil water, forage production and utilization, frequency, density and basal cover of plant species, checked cattle, received training in radiation safety, plant species identification and vegetation sampling techniques Wang, J.H., sampled soil water, forage production and utilization, frequency and density of plant species, helped with other projects on the same site, and received training in radiation safety, plant species identification and vegetation sampling techniques Patton, J.E., sampled forage production and utilization, frequency and density of plant species, edited reports, received training in plant species identification and vegetation sampling techniques Dewald, S., helped with data entry Schlecht, C. helped with data entry Wang, J.Z., graduate student estimating above-ground primary productivity through computer modeling used data collected from this project for her model, sampled soil water, forage production and utilization, frequency and density of plant species, helped with other projects on the same site, received training in radiation safety, plant species identification and vegetation sampling techniques Wang, G., Ph.D. student studying grazing management effects on plant community and soil hydrology and their relationship in the Missouri Coteau region is utilizing this project for study sites TARGET AUDIENCES: The primary target audience is the local livestock producer. This audience was reached though publication of an article in our annual report and discussion of our findings at our annual Research Roundup. The secondary audience is the scientific community this audience was reached with an article published in Rangeland Ecology and Management on the effect of grazing intensity on forage production and a poster on plant root biomass and respiration presented at the Joint Meeting of the Society for Range Management and the American Forage and Grassland Council in Louisville, KY. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The average peak forage production on silty range sites from 1992 to 2008 was 2683, 3116, 2892, 2391, and 2152 lbs/acre on the ungrazed, light, moderate, heavy, and extreme grazing intensity treatments, respectively. The average peak forage production on overflow range sites from 1993 to 2008 under the same treatments was 3305, 4104, 4141, 3934, and 2616 lbs/acre. For both types of range sites, the extreme grazing treatment produced the least forage. The light treatment is the most productive on silty range sites. On overflow range sites, the light, moderate, and heavy treatments show little difference, but moderate grazing treatment tends to be the most productive. A total of 160 species have been found on the silty range sites and 62 have shown a response to grazing based on frequency, density, or basal cover. Of the 175 species on the overflow range sites, 51 have responded to grazing. These responses include increasing or decreasing with increased grazing pressure, benefiting from moderate grazing, or invading (only appearing after heavy grazing). Of the species responding to grazing (30-40% of the total), the majority are favored by a moderate or heavy level of grazing. Since 1990, average daily gain and animal body condition scores have decreased with increasing grazing intensity. From 1991 to 2008, the average daily gain has been 1.35, 1.24, 1.08, and 0.77 lbs/head /day on the light, moderate, heavy, and extreme treatments, respectively. The corresponding average gain/acre each year over this same period has been 28.42, 54.46, 75.10, and 79.61 lbs/acre, and average body condition scores from 1994 to 2008 were 5.47, 5.36, 5.23 and 4.91 respectively. These averages vary greatly from year to year due to variation in forage, weather, cattle weights and their potential to gain. Initially, gain/acre increases as the stocking rate increases, but there comes a point when gains/acre decline. We cannot predict which stocking rate will give the maximum gain/acre in a particular year. However, at 2.15 AUM/acre, gain/acre from 1991-2008 would have averaged 74.6 lbs/acre, with a range of -45.3 lbs/acre in 2002 to 149.1 lbs/acre in 1993. Average gain/acre at the average moderate stocking rate, 1.09 AUM/acre, from 1991-2008 would have been 54.50 lbs/acre. If cattle prices were constant, then return/acre would peak at a stocking rate somewhere below maximum gain/acre, with the exact point depending on carrying costs. The change in cattle prices over the season determines the stocking rate with the maximum return/acre. The stocking rate with the maximum return/acre over the last 18 years would be 2.09 AUM/acre, with an average annual return of $36.10. Under the moderate stocking rate of 1.09 AUM/acre the average annual return would have been $27.25. The Natural Resources Conservation Service has used information obtained from this study in develop ecological site descriptions and state and transition models. Graduate students have been able to use the pastures in this study as treatments in their research. Students hired for data collection have learned skills that they can apply in their chosen profession.
Publications
- Patton, B.D., X. Dong, P.E. Nyren and A.C. Nyren. 2007. Effects of Grazing Intensity, Precipitation, and Temperature on Forage Production, Rangeland Ecology & Management, 60(6), 656-665.
- Patton, B.D., P.E. Nyren, B.S. Kreft and A.C. Nyren. 2008. Long-term grazing intensity research in the Missouri Coteau of North Dakota, North Dakota State University Central Grasslands Research Extension Center 2007 Grass and Beef Research Review, Streeter, North Dakota, North Dakota State University - Central Grasslands Research Extension Center. P. 27-33+.
- Dong, X.J., J.Z. Wang, G.J. Wang, D.J. Wang, D.J. Wang, X.Y. Zhao, B.D. Patton, S.P. Wang and P.E. Nyren. 2008. Plant root biomass and respiration on rangelands of south-central North Dakota: Impact from 18 years of cattle grazing. 2008 Joint Meeting of the Society for Range Management and the American Forage and Grassland Council, Louisville, KY, 26-31 Jan. 2008.
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Progress 10/01/06 to 09/30/07
Outputs
OUTPUTS: Prepared pastures for grazing, e.g. fixed fence, placed salt and mineral blocks, filled water troughs, trained crew in radiation safety and plant identification, maintained neutron probes, sampled and analysed soil water, took pictures of pastures, labeled and scanned slides, sampled frequency, density and basal cover data and analysed data, sampled forage production and utilization and analysed data, checked on cattle and maintained the proper number in each pasture, checked use on pastures, collected price information on cattle, shared frequency data, helped a graduate student correct and revise her paper on the morphological and physiological responses of five species to grazing intensity, prepared annual report for distribution to the public, prepared article for Rangeland Ecology and Management on the effect of grazing intensity on forage production, prepared article on the effect of species diversity on stability, spoke to Gackle-Streeter High School science class on using science to solve problems in livestock management, spoke to the public at Research Roundup on findings from the grazing intensity research study. PARTICIPANTS: Patton, B.D., principal investigator Nyren, P.E., Research Center Director Dong, X., sampled soil water, forage production and utilization, also principal investigator on an ecosystem modeling study using this project Nyren, A.C., data analysis Schmidt, D.E., handle, weigh and condition score cattle Bohn, R., sampled soil water, forage production and utilization, frequency and density of plant species Freier, A., sampled soil water, forage production and utilization, frequency and density of plant species, checked cattle Reich, E., sampled soil water, forage production and utilization, frequency and density of plant species, checked cattle, received training in radiation safety, plant species identification and vegetation sampling techniques Slaughter, K., sampled forage production and utilization, frequency and density of plant species, checked cattle, received training in radiation safety, plant species identification and vegetation sampling techniques Patton, J.E., sampled forage production and utilization, frequency and density of plant species, edited reports, received training in plant species identification and vegetation sampling techniques Wang, G., Ph.D. student studying grazing management effects on plant community and soil hydrology and their relationship in the Missouri Coteau region is utilizing this project for study sites Wang, D., graduate student studying the morphological and physiological responses of five plant species to grazing intensity collected data from the site. She received help in data collection, access to previously collected data, mentoring in data analysis and help with correcting and revising her paper Wang, J., graduate student estimating above-ground primary productivity through computer modeling used data collected from this project for her model Pan, X., graduate student evaluating ecosystem services provided by rangeland under different grazing intensities used data collected from this project TARGET AUDIENCES: The primary target audience is the local livestock producer. This audience was reached though publication of an article in our annual report and discussion of our findings at our annual Research Roundup. The secondary audience is the scientific community this audience will be reached with an article soon to be published in Rangeland Ecology and Management on the effect of grazing intensity on forage production and an article being prepared on the effect of species diversity on stability. In addition a presentation was given to the Gackle-Streeter High School science class on using science to solve problems in livestock management using this study as an example.
Impacts
The Natural Resources Conservation Service has used information obtained from this study in develop ecological site descriptions and state and transition models. Graduate students have been able to use the pastures in this study as treatments in their research. Students hired for data collection have learned skills that they can apply in their chosen profession.
Publications
- Dong, X., Nyren, P.E., Patton, B.D., Wang, G., Kreft, B.S., Nyren, A.C., Limb, R., Kirby, D. and Cihacek, L. 2006. Ecosystem CO2 exchange in a mixed-grass prairie: Effects of cattle grazing and drought. NCCC31 Annual Meeting, North Central Coordinating Committee on Ecophysiological Aspects of Forage Management, Eureka Springs, Arkansas, North Central Coordinating Committee on Ecophysiological Aspects of Forage Management.
- Patton, B.D., Nyren, P.E., Bohn, R., Kreft, B.S. and Nyren, A.C. 2007. Long-term ecological grazing intensity research in the Missouri Coteau of North Dakota, North Dakota State University Central Grasslands Research Extension Center 2006 Grass and Beef Research Review, Streeter, North Dakota, North Dakota State University - Central Grasslands Research Extension Center. P. 13-16.
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Progress 10/01/05 to 09/30/06
Outputs
A grazing intensity research project was initiated in 1989. The objectives are to: 1. Determine the effect of season long cattle grazing at different intensities on silty and overflow range sites. 2. Develop guidelines for adjusting stocking rates for cattle and forage utilization levels in pastures. 3. Maintain pastures with different grazing histories for use in various range ecosystem studies. Five treatments are included: no grazing, light, moderate, heavy and extreme grazing. Each treatment is replicated three times in pastures of about 12 ha each except that the no grazing treatment consists of six 0.12 ha exclosures, placed on both overflow and silty range sites. The pastures are grazed season long and each pasture receives the same treatment each year. The pastures are stocked each year so that when the cattle are removed in the fall, 65%, 50%, 35% and 20% of the forage produced in an average year remain on the light, moderate, heavy and extreme treatments
respectively. Adjustments in stocking pressure are made each year based on information from previous years to try and better match the desired grazing intensities. Changes in the vegetation are determined by monitoring permanent plots located on silty and overflow range sites in each pasture and the six exclosures. For the past 16 years of this study the stocking rate that would have resulted in the greatest return was 5.02 AUM/ha. However for a number of reasons we feel this stocking rate may be too heavy to recommend. First, the extreme and heavy pastures have been deteriorating in condition through the course of the study and may not be able to support the rates of gain we have seen in the past. Also we have had higher than average precipitation through much of this period. The average annual precipitation for the first 13 years of this study was 48.4 cm/year compared to the 55-year average of 45.1 cm/year. As we move into a period of drier weather, forage production and annual
gains are reduced. Both profits and losses are higher at higher stocking rates depending on the difference between spring and fall livestock prices. The producer would experience more years with negative returns at the higher stocking rates. These stocking recommendations cannot be applied to a cow-calf operation because calf gains are largely dependent on the cows' milk production. Higher stocking rates could reduce the cow's condition and conception rates and result in higher over-wintering costs to bring the cows back up to condition to calve in the spring. The pastures used in this study are still undergoing changes. But, they have a known grazing history and have developed different plant communities and productivity. The use of this resource will be coordinated with investigators conducting other ecosystem studies. Studies examining the effect of grazing intensity on non-game bird populations, the interaction of grazing intensity and fertilization, and grazing intensity and
drought and the effect of grazing intensity on the soil seed bank have just been completed. Studies on the effect of grazing intensity on plant photosynthesis and the dynamics of water and carbon/nitrogen in ecosystem are ongoing.
Impacts
The objective of this study is to determine what stocking rate would result in the greatest economic return to the livestock producer in the long run. It appears that the moderate stocking rate may be too conservative if maximizing profit is the objective. In only four out of 16 years would returns have been higher with a stocking rate less than the moderate rate of 2.64 AUM/ha. In all other years a higher stocking rate would have resulted in higher returns. For a stocker operation in this area the optimum stocking rate would fall in the range of 2.64 to 5.02 AUM/ha. As you move to lower rainfall areas farther west in the state these values would be reduced.
Publications
- Volk, J.M. 2006. Impacts of slow release phosphorus and urea on intensively and moderately grazed mixed-grass prairie and impacts of rotational grazing, intensive season-long grazing, and idle land use on soil health in the Missouri Coteau. Ph.D. Thesis, North Dakota State University, Fargo, ND.
- Salo, E. D., K. F. Higgins, B. D. Patton, K. K. Bakker, W. T. Barker, B. Kreft, and P. E. Nyren. 2004. Grazing intensity effects on vegetation, livestock and non-game birds in North Dakota mixed-grass prairie. Proceedings of the 19th North American Prairie Conference. August 8-12, 2004. Pp 205-215.
- Salo, E. D., K. F. Higgins, W. T. Barker, K. K. Bakker, and K. C. Jensen. 2004. Temporal effects of grazing regimes on non-game birds in North Dakota grasslands. Proceedings of the 19th North American Prairie Conference. August 8-12, 2004. Pp 216-224.
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Progress 10/01/04 to 09/30/05
Outputs
A grazing intensity research project was initiated in 1989. The objectives are to: 1. Determine the effect of season long cattle grazing at different intensities on silty and overflow range sites. 2. Develop guidelines for adjusting stocking rates for cattle and forage utilization levels in pastures. 3. Maintain pastures with different grazing histories for use in various range ecosystem studies. Five treatments are included: no grazing, light, moderate, heavy and extreme grazing. Each treatment is replicated three times in pastures of about 12 ha each except that the no grazing treatment consists of six 0.12 ha exclosures, placed on both overflow and silty range sites. The pastures are grazed season long and each pasture receives the same treatment each year. The pastures are stocked each year so that when the cattle are removed in the fall, 65%, 50%, 35% and 20% of the forage produced in an average year remain on the light, moderate, heavy and extreme treatments
respectively. Adjustments in stocking pressure are made each year based on information from previous years to try and better match the desired grazing intensities. Changes in the vegetation are determined by monitoring permanent plots located on silty and overflow range sites in each pasture and the six exclosures. For the past 15 years of this study the stocking rate that would have resulted in the greatest return was 5.16 AUM/ha. However for a number of reasons we feel this stocking rate may be too heavy to recommend. First, the extreme and heavy pastures have been deteriorating in condition through the course of the study and may not be able to support the rates of gain we have seen in the past. Also we have had higher than average precipitation through much of this period. The average annual precipitation for the first 13 years of this study was 48.4 cm/year compared to the 54-year average of 45.6 cm/year. As we move into a period of drier weather, forage production and annual
gains are reduced. Both profits and losses are higher at higher stocking rates depending on the difference between spring and fall livestock prices. The producer would experience more years with negative returns at the higher stocking rates. These stocking recommendations cannot be applied to a cow-calf operation because calf gains are largely dependent on the cows' milk production. Higher stocking rates could reduce the cow's condition and conception rates and result in higher over-wintering costs to bring the cows back up to condition to calve in the spring. The pastures used in this study are still undergoing changes. But, they have a known grazing history and have developed different plant communities and productivity. The use of this resource will be coordinated with investigators conducting other ecosystem studies. Studies examining the effect of grazing intensity on non-game bird populations, the interaction of grazing intensity and fertilization, and grazing intensity and
drought and the effect of grazing intensity on the soil seed bank have just been completed. Studies on the effect of grazing intensity on plant photosynthesis and the dynamics of water and carbon/nitrogen in ecosystem are ongoing.
Impacts
The objective of this study is to determine what stocking rate would result in the greatest economic return to the livestock producer in the long run. It appears that the moderate stocking rate may be too conservative if maximizing profit is the objective. In only four out of 15 years would returns have been higher with a stocking rate less than the moderate rate of 2.67 AUM/ha. In all other years a higher stocking rate would have resulted in higher returns. For a stocker operation in this area the optimum stocking rate would fall in the range of 2.67 to 5.16 AUM/ha. As you move to lower rainfall areas farther west in the state these values would be reduced.
Publications
- Limb, R., Kirby, D., and Nyren, P. 2005. Interaction of simulated drought and grazing on rangeland in North Dakota. Abst. Society for Range Management Annual Meeting, Ft. Worth, TX.
- Limb, R. F. 2005. Interaction of simulated drought and grazing intensity on northern mixed grass prairie. M.S. Thesis, North Dakota State University, Fargo. 46 p.
- Rogers , W.M., Kirby, D.R., Nyren, P.E., Patton, B.D., and DeKeyser, E.S. 2005. Grazing intensity effects on Northern Plains mixed-grass prairie. Prairie Naturalist. 37:2 73-83.
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Progress 10/01/03 to 09/30/04
Outputs
A grazing intensity research project was initiated in 1989. The objectives are to: 1. Determine the effect of season long cattle grazing at different intensities on silty and overflow range sites. 2. Develop guidelines for adjusting stocking rates for cattle and forage utilization levels in pastures. 3. Maintain pastures with different grazing histories for use in various range ecosystem studies. Five treatments are included: no grazing, light, moderate, heavy and extreme grazing. Each treatment is replicated three times in pastures of about 12 ha each except that the no grazing treatment consists of six 0.12 ha exclosures, placed on both overflow and silty range sites. The pastures are grazed season long and each pasture receives the same treatment each year. The pastures are stocked each year so that when the cattle are removed in the fall, 65%, 50%, 35% and 20% of the forage produced in an average year remain on the light, moderate, heavy and extreme treatments
respectively. Adjustments in stocking pressure are made each year based on information from previous years to try and better match the desired grazing intensities. Changes in the vegetation are determined by monitoring permanent plots located on silty and overflow range sites in each pasture and the six exclosures. For the past 14 years of this study the stocking rate that would have resulted in the greatest return was 5.16 AUM/ha. However for a number of reasons we feel this stocking rate may be too heavy to recommend. First, the extreme and heavy pastures have been deteriorating in condition through the course of the study and may not be able to support the rates of gain we have seen in the past. Also we have had higher than average precipitation through much of this period. The average annual precipitation for the first 13 years of this study was 48.4 cm/year compared to the 53-year average of 45.8 cm/year. As we move into a period of drier weather, forage production and annual
gains are reduced. Both profits and losses are higher at higher stocking rates depending on the difference between spring and fall livestock prices. The producer would experience more years with negative returns at the higher stocking rates. These stocking recommendations cannot be applied to a cow-calf operation because calf gains are largely dependent on the cows' milk production. Higher stocking rates could reduce the cow's condition and conception rates and result in higher over-wintering costs to bring the cows back up to condition to calve in the spring. The pastures used in this study are still undergoing changes. But, they have a known grazing history and have developed different plant communities and productivity. The use of this resource will be coordinated with investigators conducting other ecosystem studies. Studies examining the effect of grazing intensity on non-game bird populations, the interaction of grazing intensity and fertilization, and grazing intensity and
drought have just been completed.
Impacts
The objective of this study is to determine what stocking rate would result in the greatest economic return to the livestock producer in the long run. It appears that the moderate stocking rate may be too conservative if maximizing profit is the objective. In only three out of 14 years would returns have been higher with a stocking rate less than the moderate rate of 2.50 AUM/ha. In all other years a higher stocking rate would have resulted in higher returns. For a stocker operation in this area the optimum stocking rate would fall in the range of 2.50 to 5.16 AUM/ha. As you move to lower rainfall areas farther west in the state these values would be reduced.
Publications
- No publications reported this period
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