Integrated Residue Management Systems for Sustained Seed Yield of Kentucky Bluegrass Without Burning

2005 Annual Report for SW03-021

Project Type: Research and Education
Funds awarded in 2003: $294,243.00
Projected End Date: 12/31/2007
Matching Non-Federal Funds: $31,040.00
Region: Western
State: Idaho
Principal Investigator:
Donald Thill
University of Idaho

Integrated Residue Management Systems for Sustained Seed Yield of Kentucky Bluegrass Without Burning


Team members established a 12 ha field experiment during spring 2004. Post-harvest residue was least in bale + burn and full-load burn treatments, while seed yield was greatest in full-load graze and full-load burn. The stocking density required to remove 80% of the post-harvest residue in 30 d was 13.6 AU in bale + graze and 22.5 AU in full-load graze. The bluegrass residue met the energy requirements of a dry cow in both bale + graze and full-load graze, but not the energy requirements of a lactating cow. N supply in the fall is a critical factor impacting bluegrass seed production. Additional analyses of survey data collected from the general population were performed with an emphasis on understanding differences in perceptions about air quality as well as different types of agricultural burning.

Objectives/Performance Targets

2005 Annual WSARE Progress Report
December 14, 2005
Project Number SW03-021
Cooperative Agreement 2003-38640-13140

Project Title: Integrated Residue Management Systems for Sustained Seed Yield of Kentucky Bluegrass Without Burning

Project objectives:
Develop livestock grazing systems and/or use of emerging biotechnology alternatives that optimize biomass turnover and maintain or increase bluegrass seed yield without burning.
Compare nutrient cycling efficiency in burned, mechanically managed and grazed bluegrass systems.
Investigate above-ground insect pest and predator relationships in each bluegrass production system. Monitor diseases and weeds associated with the different treatments.
Examine the economic efficiency of each bluegrass production system including the associated production, price and financial risk.
Identify potential key socio-cultural and economic costs and benefits of livestock grazing management practices or biotechnology alternatives versus current open-burning practices.
Disseminate information to growers, field consultants, extension educators and scientific audiences.

Experimental Procedures. A field experiment was initiated during fall of 2004 in an established Kentucky bluegrass stand on a grower-cooperator farm in Latah County (a.k.a. Hatter Creek Ranch). The site was seeded in 1999 with the variety Kenblue. The experimental design was a randomized complete block with four replications. A baseline seed yield was established by harvesting and measuring seed yield by plot prior to implementing the fall residue management treatments. Residue management treatments were 1) full-load burn (historical practice), 2) bale + burn, 3) seed harvest (year 1)/chemical suppression-no seed harvest (year 2), chemical suppression-no seed harvest (year 1)/seed harvest (year 2), 4) seed harvest (year 1)/mechanical suppression-no seed harvest (year 2), mechanical suppression-no seed harvest (year 1)/seed harvest (year 2), 5) bale + mow + harrow + mow (mechanical), 6) bale + graze, and 7) full-load graze. The graze treatments were stocked at AU (animal unit) densities aimed at removing 80% of the post-harvest residue within 30 days post harvest. Percent residue removal was determined by visual estimation. Granular fertilizer was broadcast in the fall to all plots scheduled to be harvested the following summer after all of the residue removal treatments were completed. Fertilizer was not applied to treatments that were not harvested the following year, i.e. chemical suppression/seed harvest and mechanical suppression/seed harvest. Cattle were fed 1.36 kg/d/AU of a 25% crude protein (CP) and 86% IVTD (in vitro true digestibility) supplement in 2004 and 1.5 lb/d/AU of a 38% CP and 75% IVTD supplement during the first week of grazing, and 3 lb/d/AU of a 38% CP and 75% IVTD supplement weeks 2 and 3 the grazing period in 2005. Cattle were watered regularly and water consumption was measured by plot.

Seed yield was measured at the initiation of the study and every year thereafter by plot using a field scale combine to harvest the seed and weigh pads were positioned under a seed trailer to measure yield. A seed subsample was collected at harvest to determine clean seed weight, and gross seed yield was adjusted to clean seed yield. Residue management treatments were implemented immediately following seed harvest. Seed was harvested on August 10, 2004 and July 30, 2005. Residue was raked, baled and weighed by plot on August 16-17, 2004, and July 31, 2005 in the bale treatments (bale + burn, mechanical and bale + graze). Cattle were weighed and placed on the treatments on September 12, 2004, and August 15, 2005. Cattle were removed from the treatments and weighed on September 25, 2004 and September 3, 2005. Plots were burned on September 29, 2004 and August 9, 2005.

Standing and non-standing (thatch) biomass was collected from the main plots just prior to swathing and immediately following residue management treatments. Biomass measurements were made by removing all of the thatch with a wire rake from 3 randomly placed, replicate, 0.25 m2 quadrats within each plot. After removal of all non-standing biomass, the standing biomass was clipped approximately 1 cm from the soil surface and collected in a separate bag. The samples were returned to the laboratory and dried for 48 hr at 60 C. Residue samples for 2005 are currently being weighed and corrected for mineral content by ashing subsamples in a muffle furnace at 500 C for a 4-hr period. Total C and N will be measured from a composite of the three residue samples.

Baled residue was weighed and cored using a hay probe. The composite residue samples from the graze plots and the bale cores were measured for forage quality (chemical composition). Forage quality measurements included dry matter (DM), CP, acid detergent fiber (ADF), neutral detergent fiber (NDF), lignin and IVTD. Cow/calf pairs were used to graze the post-harvest residue. An animal unit was defined as 454 kg. Calves and cows received an AU measurement based on their weight percentage of 454 kg. For example, a 227 kg calf received and AU of 0.5. The bale + graze and full-load graze treatments were stocked at a density of 21 and 55 AU/ha in 2004 and 18 and 29 AU/ha in 2005 in the bale + graze and full-load graze treatments, respectively. Total available digestible dry matter (IVTD * Kentucky bluegrass residue on a 100% dry matter basis) was determined by the amount of post-harvest residue times the percent IVTD. Dry matter intake (DMI) for the grazing period was estimated by the difference in the amount of residue sampled within the quadrats before and after grazing. Animal unit DMI/d was estimated by the amount of residue removed over the number of days in the grazing period by the number of AUs grazing. Protein and IVTD intake per AU was determined by DMI/d times the percent CP and percent IVTD. Kentucky bluegrass forage value was determined by relating the IVTD and CP content of Kentucky bluegrass grazed and baled post-harvest residue to a grass hay with 90% dry matter, 6.4% CP, 51% IVTD, valued at $70.99/t.

Three replicate soil samples were collected from the 0 to 10, 10 to 20, 20 to 30 and 30 to 60 cm depths within all main plots following residue treatments. Plant available nitrogen (ammonium and nitrate) were measured within each soil depth sampled.

Data were analyzed with the general linear model procedure of SAS software (SAS Institute, 2001) with blocks and treatments as fixed effects. Data were tested for normality. Treatment effects were declared significant at P ≤ 0.05, and when ANOVA indicated, significant effects means were compared using a Least Significant Difference test (at P ≤ 0.05). Linear regression was used to determine the effect of post-harvest residue on seed yield (SAS 2000).

Results and Discussion.

Agronomic: Late summer and early fall precipitation delayed seed harvest and implementation of post-harvest residue management treatments in 2004. Seed was harvested in 2004 to establish a baseline seed yield. The baseline seed yield was not affected by block, ranging from 325 to 900 kg/ha, and averaged 630 kg/ha across blocks. Total post-harvest residue in 2004 was not correlated to seed yield in 2004, indicating that seed yield is not related to the amount of biomass produced in the growing season.

The State of Idaho restricts how late burning can occur in the fall based on air quality and smoke dispersal conditions. In 2004, post-harvest grazing was terminated prematurely to facilitate burning of adjacent burn treatments (full-load burn and bale + burn) because the State of Idaho was going to end the field burning period. The full-load graze treatment was stocked at a greater density than bale + graze, and grazing would have been completed sooner in full-load graze than bale + graze had grazing not been terminated early. Thus, terminating grazing early affected the bale + graze treatment more than the full-load graze treatment. This was evident by more post-harvest residue remaining in bale + graze than full-load graze. Considerable stand regrowth occurred prior to grazing and burning in 2004, resulting in the greater residue forage quality and a poorer burn. Burning post-harvest residue when it is wet or when stand regrowth has occurred results in a less complete burn compared to burning dry post-harvest residue, and this difference is greater in bale + burn treatments than full-load burn treatments due to less post-harvest residue to carry the fire.

Post-harvest residue was comparable across treatments prior to treatment implementation, ranging from 630 to 707 g/m2. After treatment implementation, post-harvest residue was least in bale + burn (101 g/m2), and although not significantly less than full-load burn (136 g/m2), was 51% less than full-load graze, 59% less than bale + graze, and 70% less than mechanical. Based on visual observation and aerial photographs, the amount of residue removed by the bale + burn treatment was overestimated. Aerial photographs indicated that bale + burn removed less residue than full-load graze and full-load burn, comparable amount as bale + graze, and more than mechanical. The burn in the bale + burn treatment was patchy due to fall regrowth at the time of burning, and sampling residue from the areas that burned well overestimated the amount of residue removed.

Seed yield was substantially lower in 2005 than 2004, which, in part, might have been due to the late implementation of post-harvest residue management treatments in 2004 and low plant available nitrogen (explained later). Seed yield was greatest in full-load graze (126 kg/ha), and although not significantly greater than full-load burn (105 kg/ha), was 59% greater than bale + graze, 85% greater than bale + burn, and 142% greater than mechanical. Previous research has found bale + graze and full-load graze yield comparable to each other when grazing is not ended early. Thus, full-load graze likely yielded greater than bale + graze because more post-harvest residue was removed in full-load graze due to terminating grazing early. Full-load burn yielded comparable to bale + burn and bale + graze, and 101% greater than mechanical. Bale + burn and bale + graze yielded comparable to mechanical. Seed yield in 2005 was not significantly correlated to post-harvest residue in 2004. Other studies have shown seed yield to decrease with increasing post-harvest residue. It is likely that overestimating post-harvest residue removal in the bale + burn treatment resulted in a non-significant correlation.

Forage Quality Utilization: Kentucky bluegrass dry matter intake was estimated by the number of AU grazing and the amount of post-harvest residue removed during the grazing period. Calculating the post-harvest residue dry matter intake allows for determining the stocking density required to remove the post-harvest residue. Based on this year’s research and past research, it was determined that full-load burn removes about 80% of the post-harvest residue, and non-thermal residue methods that remove at least 70% of the post-harvest residue to produce seed yields comparable to full-load burn. Post-harvest residue must be removed before the first of October in northern Idaho since removing residue later can reduce the seed yield potential. Thus, the stocking density required to remove 80% of the post-harvest residue in 30d was calculated. The dry matter intake ranged from 8.2 to 9.7 kg ha-1 and was not different between graze treatments. The stocking density required to remove 80% of the post-harvest residue in 30d was 13.6 AU in bale + graze and 22.5 AU in full-load graze. Full-load graze requires a greater stocking density since the baling operation in the bale + graze treatment removes about 50% of the post-harvest residue.

The forage quality (chemical composition) of the Kentucky bluegrass post-harvest grazed and baled residue was measured to determine its nutrient content and forage value. The chemical composition of the Kentucky bluegrass post-harvest residue was 5.1 to 8.8% ash, 3.6 to 5.2% CP, 39.0 to 39.5% ADF, 71.6 to 74.5% NDF, 47.3 to 49.1 IVTD, and 7.2 to 7.7% lignin. The forage quality of the grazed residue was improved due to late summer precipitation, which caused the stand to regrow. The new regrowth was greater in CP and IVTD and lower in fiber (ADF, NDF, and lignin) than the older mature residue.

The CP and IVTD intake was determined based on the post-harvest harvest dry matter intake and its CP and IVTD content. Measuring the CP and IVTD intake allows for calculating supplementation. One AU consumed between 358 and 503 g of CP d-1, and 4.0 to 4.7 kg of digestible dry matter (dry matter intake * IVTD) d-1 from the Kentucky bluegrass post-harvest residue. Crude protein and digestible dry matter intake was not significantly different between graze treatments, although tended to be greater in full-load graze than bale + graze since dry matter intake tended to be greater in full-load graze. The CP and digestible dry matter requirements are greater in a lactating cow than a dry cow due to greater maintenance energy and protein requirements. The Kentucky bluegrass residue met the energy requirements of a dry cow in both bale + graze and full-load graze, but did not meet the energy requirements of a lactating cow. The Kentucky bluegrass residue did not meet the CP requirements of a dry or lactating cow in either treatment. Thus, CP will likely need to be supplemented and energy might not need to be supplemented to cattle grazing Kentucky bluegrass residue.

Kentucky bluegrass forage economic value was determined based on its nutrient composition relative to grass hay composition and value. Baled Kentucky bluegrass is worth approximately $33 t-1 ($30 ton-1). The grazed residue in bale + graze was worth $55 ha-1 and in full-load graze was worth $240 ha-1. The value of the grazed residue would have been worth more if grazing was not prematurely ended, since more residue would have been grazed. If grazing was not prematurely ended, the value of the bale + graze residue would have been worth $74 ha-1.

Residue and Nutrient Cycling: Residue removal in the full-load burn and bale + burn treatments was similar and ranged from 91 to 93% removal of standing biomass and 70 to 84% removal of non-standing biomass. The graze treatment resulted in the removal of 81% of the standing biomass and 64% of the non-standing biomass. Baling and grazing was not as efficient at reducing the biomass that was left standing after harvest, because cattle were removed earlier than expected to allow the grower to burn field and burn treatment residue (69% removal). Residue removal in the mechanical treatment was extremely low and averaged 22% of standing and 44% of non-standing biomass. Overall the graze treatment came much closer to achieving residue removal at rates similar to those measured in the full-load burn treatment.

Soil samples collected in 2004 indicate that plant available nitrogen (NH4+-N + NO3–N) in the first 30 cm of soil was severely depleted through plant uptake and/or leaching. Ammonium concentrations were consistently low (< 2 g g-1) at each depth with no detectable differences between residue management treatments. Nitrate concentrations generally increased with depth, especially in the full-load burn treatment. The relatively high nitrate concentrations with depth indicate nitrate leaching. As part of a separate fertilizer timing study, soil samples were collected in subplots treated in an identical manner as the main plots. Analysis of these samples indicate that approximately one month following fertilizer application in the fall, the majority of nitrogen was already in the nitrate form. It appears that fertilizer nitrogen (added in the form of ammonium) was rapidly converted to nitrate through the process of nitrification. This resulted in a large pool of nitrogen that was potentially lost through the fall and winter months due to leaching. By spring 2005, plant available nitrogen levels in the soil were once again at very low levels (6.5 mg g-1 N in the 0-to 30-cm depth and 4.5 mg g-1 N in the 30-to 60-cm depth). Low N fertility may have limited yields at this site. Nitrogen supply in the fall is a critical factor impacting Kentucky bluegrass seed production. Based on site specific soil and climatic conditions nitrification and nitrate leaching may be favored during this critical period. These factors need to be balanced when determining fertilizer rates and timings to maximize growth and N loss beyond the root zone.
Insect Pest and Predators: The objects of this part of the project were to evaluate pest and beneficial insect population changes across thermal and nonthermal production systems for Kentucky bluegrass seed production in Idaho. The focus of the work was on the bluegrass billbug, which damage stems and crowns of the grass, and the carabid beetles that are general predators in the grass seed system.

The common, and only, billbug species found in the WSARE site thus far is the Denver billbug, (Curculionidae: Sphenophorus cicatristriatus). The billbugs overwinter as adults, then mate and lay eggs in the spring. The current data show the general phenology of the billbug, but the data are variable. The average number of billbugs per treatment vastly varies by date, probably due to weather, and the specific treatments in a particular plot. These data have not been analyzed yet to assess a treatment effects, but such analyses are forthcoming.

Carabids are predaceous ground beetles. The most prevalent species complexes are Amara spp. and Harpalus spp. Carabids are often grouped by their overwintering habits. Beetle species that mate in the fall and overwinter as larvae are called “autumn breeders” and those that mate in the spring and overwinter as adults are called “spring breeders.” Data somewhat distinguish between autumn and spring breeders. N. nitens and P. melanarius, and C. cancelatum are all spring breeders. These data have not been assigned by treatments for each date and the data are scheduled to be analyzed within the next few weeks.

One important note is that the numbers of both billbugs and carabids is considerably low. This is most likely because the whole field was burned rather recently. Many of these beetles are still in the establishment phase in the plots that are no longer burned. Thus, these data may change significantly within the next 3-5 years, particularly in the nonthermal treatments.

Enhanced Residue Decomposition: Increasing regulations and restrictions on the burning of Kentucky bluegrass fields have created the need for cost effective alternatives to maintain the viability of the crop. As a part of the current multi-faceted research program funded by this grant, we are examining the effects of Streptomyces hygroscopicus when it is applied as a spore formulation to subplots within the Kentucky bluegrass field plots to determine if strain YCED9 will enhance the degradation rates of the lignocellulosic residues within the field and thereby enhance bluegrass growth and maintain or increase seed yield in the absence of burning and/or in combination with other treatments.

The field application of S. hygroscopicus, YCED9 was done in April 2005 to the following treatments: full-load burn, mechanical, bale + burn, bale + graze, and full-load graze. For replication, this was repeated over four different plots. Inoculation was done by mixing spores of strain YCED9 [1×108 colony forming units (cfu’s) in a whey carrier] into one gallon of water. The whey acts as a water soluble carrier and serves as an initial supplemental carbon source for the microbe as it begins to grow and colonize the grass residues in the field. The mixture was then sprayed over the 10 x 30 foot plot at a rate of one liter per minute. This gave total bacterial inoculant coverage of 1×106 cfu/ft2. When the fields were harvested in July, representative square samples (1 foot x 1 foot) from the treatments were swathed by hand. The Kentucky bluegrass was then dried, and clean seed weight determined.

Residue and seed yields will be compared between each of the treatments and controls to determine what effects YECD9 inoculation had in comparison to the plots not inoculated with the microbe. The seed samples are being sifted to obtain a ‘clean weight’ before final weight measures can be obtained. The accumulated data will be analyzed and reported to the research team during January 2006.

The plots from this year’s research have been marked with stakes to preserve them for the coming year. We anticipate repeating the inoculations for a second year of study, with a target date for inoculation of April 2006. We anticipate that multiple year inoculations will be required to see statistically significant changes in residue decomposition rates and seed yields as compared to uninoculated, but otherwise similar treatments.

Socio-economic: This part of the project examines the economic efficiency of each bluegrass production system including the associated production, price, and financial risk. It also examines potential key socio-cultural and economic costs and benefits of livestock grazing management practices or biotechnology alternatives versus current open-burning practices. The economic analysis will be completed after all biological data are collected. Preliminary analyses of the data have begun.

Additional analyses of survey data collected from the general population (see 2004 Report for methodology), were performed with an emphasis on understanding differences in perceptions about air quality as well as different types of agricultural burning.

When asked about general air quality, the largest percentages of respondents indicated the worst months in the region occur in August (46%) and September (29%), correlating to the peak season for agricultural activities such as harvest and burning as well as forest fires during the summer of 2003, which was the relevant season given the timing of the survey. Only a small percentage of respondents indicated they recognized air quality concerns in their community during winter months such as January (10%), February (4%), and December (14%).

However, when asked to rate the general air quality for the region over the course of the entire year, only 7% of respondents indicated they thought air quality was “poor” or “very poor”. In contrast, the large majority of respondents rated the overall air quality either as “good” (48%) or “very good” (37%). Combining the results confirms the likelihood that a perception exists among the public that air quality concerns may be at a peak during the late summer which correlates to the field burning season, but that overall the majority of individuals perceive that air quality in the region remains quite good.

Over 80% of all respondents indicated they did not distinguish between different types of agricultural burning, which confounds perceptions of the origins of air quality concerns given the multiple sources of air quality concerns occurring in the Panhandle region. The distribution of response from those surveyed about the overall level to which the smoke from agricultural burning is an impact to normal family activities was determined. Those indicating a ‘major impact’ (14%) were fewer than those indicating the smoke ‘did not bother them at all’ (31%). However, almost the reverse pattern was found in the more moderate categories of ‘somewhat bothersome’ (29%) and ‘do not mind’ (13%). An additional 13% of those surveyed indicated they were ‘indifferent’ toward whether the smoke from agricultural burning impacted normal family activities.

Overall, the survey data yields mixed results among the population as to whether agricultural burning impacts present air quality problems. The perceptions do exist among those surveyed that summer months may have poor air quality in northern Idaho, and that agricultural burning contributes to this environmental condition. However, overall, the respondents also indicated a strong sense of acceptable air quality in the region.

Information Dissemination: The extension program is a critical link between the bluegrass team, the region’s grass seed industry, and the general public. The extension program has disseminated information through numerous local, regional and national presentations, the bluegrass list server, information database, website, mass media publications and interviews, extension publications, individual contacts, and field tours. Two extension publications 1) “Kentucky Bluegrass Production” and 2) “Kentucky Bluegrass Growth, Development, and Seed Production” were published this past year. Information has been disseminated to college and elementary students through guest class lectures, activity workbooks, and student field tours. Information needs and preferred method of information delivery were obtained from Idaho and Washington producers, and that information was used to help prioritize research and extension objectives. The extension program has helped develop research projects that can be practically implemented by practitioners, sped the process of disseminating information to producers and public, assisted producers adopting new best management practices, and fostered a cooperative atmosphere between research scientists and the grass seed industry.

Publications and Presentations:
Holmon, J.D. and D.C. Thill. 2005. Kentucky bluegrass growth, development, and seed production. Bul. 843, p. 12.
Holman, J.D. and D.C.Thill. 2005. Kentucky bluegrass production. Bul. 842, p. 12
Wulfhorst, J.D., L.W. Van Tassell, B. Johnson, John Holmon, and D. Thill. 2005. An industry amidst conflict and change: Practices and perceptions among Idaho’s bluegrass seed producers. (in press).
Holman, J, D. Thill, J. Johnson-Maynard, K. Umiker, C. Hunt, and J. McCaffrey. 2005. Effect of reduced-burn and no-burn residue management on Kentucky bluegrass seed production. Proc. Western Soc. Crop Sci.
Reed, J., D. Thill, and J. Holman. 2004. Herbicide suppression of Kentucky bluegrass stands in an alternate year production system. Proc. ASA-CSSA-SSSA.
Holman, J., D. Thill, J. Johnson-Maynard, C. Hunt, J. McCaffrey, L. Van Tassell, J.D. Wulfhorst, D. Crawford, and J. Reed. 2004. A team approach to addressing a critical grass seed production issue. Proc. ASA-CSSA-SSSA.
Holman, J., D. Thill, C. Hunt, and J. Johnson-Maynard. 2004. Integration of livestock into Kentucky bluegrass seed production systems. Proc. ASA-CSSA-SSSA.
Thill, D.C., J.D. Holman, et. al. 2005. Integration of cattle as a non-thermal alternative to managing Kentucky bluegrass residue. Field Day, Aug. 31, Potlatch, ID.
Thill, D.C. 2005. Kentucky bluegrass field tours. Worley, Idaho, June 2; Potlatch, Idaho, June 9.


Two years of research have been completed (see Results and Discussion section) and the third and final year of the project is in progress.

Impacts and Contributions/Outcomes

Increasing Producer Knowledge Base:
New residue management systems will be provided to grass seed growers that greatly reduce post-harvest burning of residue and improve air quality, while minimizing soil erosion.
Integration of plant and animal factors will create bluegrass residue management systems that are acceptable to the general public and are economically beneficial to both grass seed and livestock producers in the Pacific Northwest.
Eliminating the loss of nutrients from burning and residue removal will improve the on-farm nutrient balance and reduce dependence on inorganic fertilizers. Understanding the importance of nutrient release in agronomic residues will help us to develop more economically efficient fertilizer recommendations while further protecting water quality.
Maintaining or increasing the acreage of this perennial crop will protect against soil erosion, improving soil and water quality.

Information Dissemination:
Growers and industry representatives have access to information through field tours scheduled at various times during the three-year production cycle to demonstrate residue management effects on livestock and grass seed production.
Meetings are conducted throughout the region and include grass seed and livestock producers, as well as research and extension personnel.
A web site was constructed to provide grass seed and livestock producers access to all information associated with grass seed production.
Results are published in the appropriate professional journals, extension publications, and disseminated at professional meetings.

Number of Acres/Animals Impacted:
Approximately 62,000 ha of grass seed are produced in the Pacific Northwest annually. It is estimated that producers will adopt the use of livestock to remove residue on 10% of the acres, or about 6,200 ha. With a stocking density of 14 AU ha-1, this would impact about 87,000 head of cattle annually. In addition, another 30% likely will adopt mechanical residue removal plus enhanced microbial decomposition.

Actual Positive Economic Impact (Dollar Value) to Farm/Ranch Families and Communities:
Under current bluegrass production practices where field burning is not allowed, return per ha is reduced by as much as $398. If these proposed bluegrass production practices (livestock grazing and/or microbiologically enhanced decomposition) are successful, an adoption rate of at least 30% could be expected given that bluegrass burning may soon be greatly restricted or outlawed in Idaho as it has already been in Washington. Given this adoption rate, direct revenue to grass seed producers in the region would increase by $4,981,800. Using a multiplier of 1.8, direct and indirect benefits to the region would be over $8.9 million from adoption of these practices in Northern Idaho alone, with the potential of increased benefits if producers in Washington and Oregon also adopt these practices. Additionally, assuming a 50% adoption rate in Northern Idaho, the economic value of reduced soil erosion from maintaining farmland in bluegrass production could equate to an additional saving of over $300,000 per year using erosion studies by Walker et al. 1987.
Beef cow-calf producers typically operate on an extremely narrow profit margin and often operate at a net loss. Consequently, cow-calf producers would be highly motivated to seek methods of reducing operating costs. One possible method of improving enterprise profitability would be to harvest the Kentucky bluegrass stand for hay rather than seed one year during the life of the stand. Harvesting the Kentucky bluegrass as hay would not require livestock ownership since the hay could be sold on the open market for about $71 ton-1. Feed costs incurred during the fall and winter are the largest single cost for the cow-calf producer and often exceed 50% of the total cost of production of a weaned calf ($180 to $250 per cow-calf unit). It is reasonable to assume that identification of prudent grazing practices could reduce fall/winter feeding costs by $40 to $60 per cow, thereby greatly widening the profit margin. We estimate that this benefit could be achieved from approximately 0.4 ha of grass seed residue and fall regrowth.
There will be measurable social and cultural impacts associated with the potential changes from moving to a non-thermal production system. Farmer, rancher, and community acceptance will increase with proper assessment of shifts in norms, customs, and practices related to a regional heritage and identity evolved in conjunction with burning practices.


Jodi Johnson-Maynard
Associate Professor of Soil Science
University of Idaho
PO Box 442339
Moscow, ID 83844-2339
Office Phone: 2088859245
J.D. Wulfhorst
Associate Professor of Rural Sociology
University of Idaho
PO Box 442334
Moscow, ID 83844-2334
Office Phone: 2088857645
Joe McCaffrey
Professor of Entomology
University of Idaho
PO Box 442339
Moscow, ID 83844-2339
Office Phone: 2088857548
Don Crawford
Professor of Microbiology
University of Idaho
PO Box 443052
Moscow, ID 83844-3052
Office Phone: 2088856001
Carl Hunt
Professor of Animal Science
University of Idaho
PO Box 442330
Moscow, ID 83844-2330
Office Phone: 2088856932
Larry Van Tassell
Professor of Agricultural Economics
University of Idaho
PO Box442334
Moscow, ID 83844-2334
Office Phone: 2088857869