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

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

Summary

Team members established a 12 ha field experiment during spring 2004. Following harvest in 2005, post-harvest residue was least in the full-load burn and bale then burn treatments, while seed yield was greatest in the full-load burn and bale-then-graze treatments. The stocking density required to remove 80% of the post-harvest residue in 30 d was 13.2 AU in bale-then-graze and 19.2 AU in full-load graze. The bluegrass residue met the energy requirements of a dry cow in bale-then-graze and full-load graze treatments, but not the energy requirements of a lactating cow. N supply in the fall is a critical factor affecting bluegrass seed production. Additional analyses of survey data collected from the general population were performed with an emphasis on the timeline for preferred burning restrictions and source of compensation associated with possible burn bans. Economic analyses were conducted on cost to provide water for cattle grazing in bluegrass fields and bluegrass suppression treatments.

Objectives/Performance Targets

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 aboveground 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.

Accomplishments/Milestones

We have completed the third and final year of the project and are analyzing the data. Thus, we are submitting a third progress report (See the Results and Discussion section). We will submit a final report in September 2007.

Experimental Procedures.

We initiated a field experiment 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 grower seeded the grass in 1999 with the variety ‘Kenblue.’ The experimental design was a randomized complete block with four replications. We established a baseline seed yield by harvesting and measuring seed yield by plot prior to implementing the residue management treatments in the fall. Residue management treatments were: full-load burn (historical practice); bale-then-burn; seed harvest (year 1) then chemical suppression-no seed harvest (year 2), chemical suppression-no seed harvest (year 1) then seed harvest (year 2); seed harvest (year 1) then mechanical suppression-no seed harvest (year 2), mechanical suppression-no seed harvest (year 1) then seed harvest (year 2); bale-then-mow-then-harrow (mechanical); bale-then-graze; and full-load graze. We stocked the graze treatments at AU (animal unit) densities aimed at removing 80% of the post-harvest residue within 30 days post harvest. We determined percent residue removal 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. We did not apply fertilizer to treatments that were not harvested the following year, i.e. chemical suppression/seed harvest and mechanical suppression/seed harvest. Seed yield was measured every year 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 sub-sample 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 July 30, 2005. Residue was raked, baled, and weighed by plot on July 31, 2005, in the bale treatments (bale/burn, mechanical, and bale/graze). Plots were burned on August 9, 2005. Cattle were weighed and placed on the treatments on August 15, 2005. Cattle were removed from the treatments and weighed on September 3, 2005. Urea fertilizer was broadcast applied at 268 kg/ha on October 24, 2005. Soil samples taken in spring 2006 indicated low levels of plant available nitrogen present, so 30 kg/ha of nitrogen was applied to all plots that would be harvested in 2006. Grass was swathed on July 4 and seed was harvested on July 27, 2006.

Standing and non-standing (thatch) biomass samples were collected from the main plots just prior to and immediately following residue management treatments to determine the percent biomass removal. Biomass measurements were made by removing all of the thatch with a wire rake from 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. Residue samples were returned to the laboratory, oven dried at 60 C for 48 hours, and weighed. Residue and soil samples for 2006 are currently being analyzed.

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), crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), lignin, and in vitro true digestibility (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 graze treatments were stocked at a density 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 for 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/Mg.

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 swathing. Plant available nitrogen (ammonium and nitrate) was measured within each soil depth sampled.

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 and 2006 to the following treatments: full-load burn, mechanical, bale then burn, bale then 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. 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.

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).

Results and Discussion.

Agronomic: Post-harvest residue level prior to removal treatments was greatest in the mechanical and least in the bale then burn. After treatment implementation, post-harvest residue was least in the burn plots (1370 and 1390 kg/ha) compared to grazing and mechanical treatments. Full-load burn and bale-then-burn treatments removed 77-81% of the residue compared to 62-66% with graze treatments and 34% with the mechanical removal treatment. Seed yield in 2006 was not significantly correlated to post-harvest residue in 2005. Seed yield was greatest in full-load burn (203 kg/ha), and although not significantly greater than bale-then-graze (194 kg/ha), was 149% greater than full-load graze, 172% greater than bale-then-burn, and 383% greater than mechanical.

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 current and previous 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 produce seed yields comparable to full-load burn. Post-harvest residue must be removed before October 1 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 30 days (30d) was calculated. The dry matter intake ranged from about 8 to 9.4 kg/ha and was not different between graze treatments. The stocking density required to remove 80% of the post-harvest residue in 30d was 13.2 AU in bale then graze and 19.2 AU in full load graze. Full-load graze requires a greater stocking density since the baling operation in the bale then 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 6.3 to 7.9% ash, 6.7 to 7.4% CP, 33.4 to 36.1% ADF, 65.4 to 71.9 NDF, 45.6 to 54.3 IVTD, and 3.5 to 5.9% lignin. The bale-then-graze treatment residue (after bale removal) had higher contents of ash, NDF and lignin, and lower IVTD than the graze treatment residue, thus lowering the forage quality in the bale-then-graze treatment. The baled residue from the bale then graze treatment had low ash, ADF, and NDF content, and high IVTD content. The baled residue was of higher forage quality than the remaining residue, which was likely due to the baled residue containing a greater percent of leaf material and a lower percentage of stem material than the remaining residue. CP did not differ among treatments.

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 584 and 687 g of CP/day, and 3.4 to 4.9 kg of DDM/day from the Kentucky bluegrass post-harvest residue. CP and DDM intake were not significantly different between graze treatments, although tended to be greater in full-load graze than bale-then-graze since dry matter intake tended to be greater in full-load graze. The crude protein 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 in the full-load graze treatment exceeded the energy requirements for a dry cow and a cow in middle pregnancy. Little supplement is required (224g/d of CP and 0.4 kg/d of DDM) to meet the energy requirements of a lactating cow 3 to 4 months postpartum. The bale-then-graze treatment exceeded the energy requirements of a dry cow, and required little supplementation in a cow in middle pregnancy and a cow post partum.

Kentucky bluegrass forage economic value was determined based on its nutrient composition relative to grass hay composition and value. In 2005, baled Kentucky bluegrass was worth approximately $71/Mg and $194/ha compared to grass hay at $70.99/Mg. The grazed residue in bale then graze was worth $137/ha and in full-load graze was worth $326/ha.

Residue and Nutrient Cycling: Residue removal was highest in the burn treatments. Full-load burn removed 92% of standing and 74% of non-standing residue. The bale-then-burn treatment removed 83% of standing and 74% of the non-standing residue. Removal of standing biomass in the cattle treatments equaled 76% in the graze and 81% in the bale-then-graze treatment. Removal of non-standing residue was also similar within these treatments ranging from 54% in graze to 59% in the bale-then-graze treatment. The mechanical treatment was the least effective at removing residue (26% removal of standing biomass and 45% removal of non-standing).

Soil samples collected in 2004 (see last year’s report) and 2005 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 micrograms/g in 2004 and < 5 micrograms/g in 2005) at each depth with no detectable differences between residue management treatments. Similar to 2004 data, nitrate concentrations increase with depth, indicating loss below the root zone, especially in the full load burn treatment. Low N fertility may have limited yields at this site. Nitrogen supply in the fall is a critical factor affecting 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. Plant available P levels were all above the recommended levels for bluegrass in northern Idaho. Available P concentrations were highest within the 0-to 10-cm depth of the graze treatment. Higher plant-available P in the graze treatment may be due to recycling of P added through supplemental cattle feed (3%N and 0.4%P) and due to P being returned to the soil after cattle digestion. Soil samples collected in 2006 will also be analyzed for available P to help determine the overall impact of grazing on P availability.
Insect Pest and Predators: We analyzed all of our billbug data and there were no significant differences (P>0.05) in their numbers among treatments. The variation within the low numbers of weevils recovered provided for poor statistical power of the data. A population model of the billbug numbers accumulation over time suggested that the chemically suppressed treatments may have the lowest numbers of active adults. However, this result is not definitive considering the limited number of weevils collected. Another study that looked at billbug adult populations in Oregon also collected rather low numbers of adult weevils in pitfall samples. Pitfall trap samples are always recommended for sampling them in turf grass; however, grass seed fields have much taller grass that probably hinders the movement of the billbugs, thereby leading to poor catches. We need to develop better sampling tools for the billbugs in these settings.

Species of predacious carabid beetles were grouped together by genus because their numbers were too low to analyze by species. The genus Amara was the only one to show significant differences (P<0.05) among treatments during the 2003 and 2005 sampling years. There was a major shift of abundances of beetles from mostly Amara spp. to mostly Agonum spp. between 2003 and 2004. We used frequency analyses to examine the change in species/genus composition, but little could be explained. The big question is why would this happen? Except for the Amara spp., there were no other significant treatment effects (P>0.05) among the beetles groups.

There were no significant differences (P>0.05) in spider numbers among treatments. Again, it appeared that the grazed and mechanical treatments had the highest numbers; however, statistical contrasts of the population curves did not confirm these observations.

The overall results of this year’s work suggest that thermal and nonthermal treatments had little effect on these important arthropod groups; however, this could be a function of several factors including the presence or absence of food. The beneficial insects and spiders are mobile by either flying and walking (carabids) or just walking (spiders). The billbugs also generally walk to the fields. Thus, the availability of field margins, woodlots, and other “reservoirs” can make a difference in the numbers of pest and beneficial species present, irrespective of field treatment. Consequently, this is a good news-bad news situation. However, further studies on the different responses of pest and beneficial insects to specific reservoir habits could allow for better management of those species.

Enhanced Residue Decomposition: The conclusions we can reach from our part of the research are that in the Streptomyces-inoculated plots, residue decomposition rates were not significantly improved as compared to the non-inoculated plots, over the period of the field experiments. It would take another season’s worth of data to see any differences, if there are any. On the other hand, inoculation did reduce fungal population levels and diversity as compared to non-inoculated controls. These results indicate that Streptomyces inoculations might be useful in controlling fungal diseases that might appear in Kentucky bluegrass fields in the absence of field burning. Additional research over several more seasons is needed to confirm this potential.

Socio-economic: Additional data were analyzed from the public and producer surveys conducted in earlier project phases. One of the critical dilemmas regarding alternative management systems is assessing the level of understanding about tradeoff effects among those affected. Within the public survey, individuals who stated they would like to reduce or eliminate bluegrass burning were asked a follow-up question regarding how quickly they would like to see new regulations put into place. The largest percentage of respondents (44%) suggested that new restrictions be phased in within one to two years. The remaining individuals were divided between enforcing new regulations immediately (30%) and phasing in new regulations over a longer period of three to five years (26%). When the results were examined separately for those individuals supporting a total ban versus those individuals supporting increased restrictions, those favoring a total ban were more in favor of imposing restrictions immediately. Those individuals that favored increased restrictions on burning without banning it entirely suggested phasing in any new restrictions over a period of 1-2 years. The results from these questions appear to indicate that while most people do not want any changes in the current regulations, those individuals who want the most restrictions on burning also want to see those restrictions in place the quickest.

Previous data analyses reveal that many within the public feel the farmers ought to be responsible to pay the costs of no-burn alternatives. However, this tendency is explained in part by analyzing the relationship between the respondents’ relation to farming with alternative compensation sources. Comparison analyses between producer and public responses were conducted using an index of degree of farming background and relationship. The public perception is explained in part by analyzing the relationship between the respondents’ relation to farming with alternative compensation sources. While those with higher levels of a farming background or relation to farming vary across private, state, and federal payment options, those with no farming background tend to strongly prefer the farmers bear these potential costs.

Economics of grazing cattle on bluegrass residue: Cost of hauling water for consumption by livestock grazing on bluegrass residue was examined. The four possibilities examined were using a pickup and trailer, mounting a tank on an old farm truck, mounting a tank on a tandem truck, and using a tractor truck with a tanker trailer. Total ownership and operating costs for providing water from distances ranging from 1 to 15 miles and for 30 to 515 head of cattle were examined. Vehicle, trailer, and tank costs were obtained from regional newspaper ads. The most economical method of providing water from a short hauling distance for a small number of cattle was using an older 2½ ton truck with a 1,600 gallon water tank mounted on the truck bed. Over a 45-day grazing period, the watering cost for 30 head of cows was $12.80 per day. As the distance hauled and number of head of livestock increased the most economical mode of water transportation was with a tractor truck and a 7,800 gallon tanker trailer. Over a 45-day grazing period, the total watering costs for 515 head of cattle, with water being hauled 15 miles, was $116.62 per day.

Economic Results of Suppression Treatments: A stochastic simulation model was developed using cost and return estimates of the bluegrass seed production methods examined (mechanical, chemical suppression, and hay suppression) along with necessary rotation crops (spring and winter wheat). Prices of bluegrass seed, hay, and wheat were modeled using harmonic regression techniques to capture the inherent price cycles. On-farm bluegrass seed yields (mechanical treatment) were modeled using a log-linear function and suppression yields were represented by empirical distributions conditional on mechanical treatment yields. Weibull distributions were used to model spring and fall wheat yields. The simulation model was used to report the economic feasibility of each treatment for the expected stand life. Because of unequal treatment lives, annual annuities from the net present values of the net returns to land, management, and risk were developed.

Though mean net returns from all treatments were negative, the highest net returns per acre were realized from the mechanical treatment (-$11.41), followed by the chemical suppression treatment (-$22.30). The annual returns per acre for the mechanical and hay suppression treatments were close at -$28.03 and -$31.59 due to an assumed 15% seed yield reduction from the chemical suppression seed yields. This occurred because of limited stand density thinning by these latter treatments. The mechanical treatment also dominated all suppression treatments when compared by second-degree stochastic dominance. The mechanical treatment would have dominated the others by first degree stochastic dominance if not for the higher probability of extremely negative returns obtained from iterations when seed yields were low and stand establishments failed. Chemical suppression was preferred by all levels of risk aversion over the mechanical and hay suppression treatments as determined by first-degree stochastic dominance, while mechanical suppression was likewise preferred to hay suppression.

The sensitivity of the suppression yield assumptions was tested by varying suppression yield distributions. Given the cost of suppression and the absence of seed production during the suppression fallow year, suppression techniques are not profitable unless yields can be increased by 25 to 50 percent over those assumed in the base conditions.

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 during 2005. 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.

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 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 Affected:

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 affect about 87,000 head of cattle annually. In addition, another 30% likely will adopt mechanical residue removal.

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 Mg. Feed costs incurred during the fall and winter is the largest single cost for the cow-calf producer and often exceeds 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.

Publications (2006):

Crawford, D. L. M. Kowalski, M. A. Roberts, G. Merrell, and L. A. Deobald. 2005. Discovery, development and commercialization of a microbial antifungal biocontrol agent, Streptomcyes lydicus WYEC108: history of a decade long endeavor. Society for Industrial Microbiology News. 55: 88 -95.

Holman, J.D. 2005. Kentucky bluegrass (Poa pratensis L.) non-thermal and reduced thermal residue management and forage utilization. Ph.D. Dissertation, University of Idaho.

Holman, J. D., Hunt, C. W., Thill, D. C. 2006. An evaluation of structural composition, growth stage, and cultivar affects on Kentucky bluegrass forage yield and nutrient composition. Agronomy Journal. (In press)

Holman, J., Hunt, C. W., Johnson-Maynard, J., Van Tassell, L., Thill, D. C. 2006. Integration of livestock into Kentucky bluegrass seed production systems as a non-thermal residue management practice. Agronomy Journal. (In press)

Holman, J., C. Hunt, and D. Thill. 2006. Post harvest affects on Kentucky bluegrass forage quality. In Annual meetings abstract [CD-ROM]. ASA, CSSA, and SSSA.

Holman, J., D. Thill, J. Johnson-Maynard, C. Hunt, L. Van Tassell, J.D. Wulfhorst, J.
McCaffrey. 2006. University of Idaho Kentucky bluegrass seed production research update. Ag Equipment Power. Clinton Publishing, Inc. ISSN. 1535-9409.

Min Jin Kang, Doctor of Philosophy (Ph.D.), Microbiology, Molecular Biology and Biochemistry. 2006. Characterization of Novel Members of the Streptomyces violaceusniger Clade and Characterization of Antibiotic Biosynthesis Genes from Streptomyces lydicus WYEC108. Ph.D. Thesis, University of Idaho, Moscow, ID.

Morgan Poloni, Master of Science (Non-Thesis M.S.), Environmental Science, May 2006. Thesis Project Title: Alternatives to Field Burning of Kentucky Bluegrass. University of Idaho, Moscow, ID.

Robertson, J.D., J. Johnson-Maynard, K. Umliker, and D. Thill. 2006. Residue and nitrogen dynamics in northern Idaho Kentucky bluegrass seed. Proc. ASA-CSSA-SSSA.

Strap, J. L. and D. L. Crawford. 2006. Microbial ecology of Streptomyces in soil and
rhizospheres. In, Molecular Techniques for Soil and Rhizosphere Microorganisms.
J. E. Cooper and J. R. Rao, Editors. CABI Publishing Co., Wallingford, Oxfordshire,
UK. In Press.

Wolfley, J., Van Tassell, L., Smathers, R., Holman, J., Thill, D. C., Reed, J. (2006). Economic analysis of experimental thermal and non-thermal residue management systems for Kentucky bluegrass seed. University of Idaho Extension Bulletin. UI Bulletin 847. pp. 19

Wolfey, J., L. Van Tassell, D. Thill, and J. Holman. “Evaluation of Non-thermal methods in the production of Kentucky bluegrass seed.” Selected paper at the 2006 Western Agricultural Economics Association Meetings, Anchorage, AK. June 2006. Journal of Agricultural and Resource Economics 31,3 (2006): in print.

Wulfhorst, J.D., L. Van Tassell, B. Johnson, J.Holman, and D. Thill. 2006. An industry amidst conflict and change: Practices and perceptions of Idaho’s bluegrass seed producers. UI Res. Bull. 165

Wulfhorst, J. D., Stephanie L. Kane, Larry W. Van Tassell, Beth Johnson, Romuald Afatchao, Katelyn Peterson, and Bernardo Alvarez. 2006. Public Attitudes and Perceptions of Air Quality and Bluegrass Seed Residue Burning in Northern Idaho. UI Res. 166.

Presentations (2006):

Holman, J., D. Thill, J. Johnson-Maynard, J. McCaffrey, L. Van Tassell, J.D. Wulfhorst, C. Hunt. “University of Idaho Kentucky bluegrass field tour”. University of Idaho, Worley, ID. (May 23, 2006).

Holman, J., D. Thill, J. Johnson-Maynard, J. McCaffrey, L. Van Tassell, J.D. Wulfhorst, C. Hunt. “University of Idaho Kentucky bluegrass field tour”. University of Idaho, Potlatch, ID. (June 6, 2006).

Holman, J., D. Thill, J. Johnson-Maynard, C. Hunt, L. Van Tassell, J.D. Wulfhorst, J.
McCaffrey. 2006. Kentucky bluegrass research. Idaho State Dept. of Agriculture Crop Residue Disposal Program Training.

Holman, J. 2006. Reduced and non-burn residue management alternatives in Kentucky bluegrass
seed production fields. Sports Turf Magazine. March 22, 2006.

Collaborators: