Progress 07/01/00 to 06/30/05

Outputs
At the Mushroom Test Demonstration Facility (MTDF) the most advanced odor management technology for Phase I substrate preparation was installed. This forced aerated floor bunker system was used to complete numerous experiments on mushroom substrate preparation management and how to reduce emissions during the process. The project evaluated different aeration management schemes, formulations and substrate characteristics and their impact on mushroom composting, fresh mushroom yields and quality. Research was conducted to determine whether current composting formulations provided sufficient levels of micronutrients in the substrate to obtain optimal yield potentials. Results suggested that the supply of micronutrients in compost might sometimes be inadequate to support optimum crop yields. Another cultural method developed in this project was the addition of sodium selenite to the irrigation water of fresh mushrooms. This irrigation method not only improved postharvest quality but also incorporated the nutritional benefits of selenium into fresh mushrooms. Fresh mushrooms irrigated with proper amounts of sodium selenite have contained about 100% of the current US RDA for selenium in one serving and elevated levels of selenium in the diet may decrease incidences of certain forms of cancer. The addition of both calcium and selenium to mushrooms via the irrigation water is a cost-effective and safe means to improve mushroom quality and nutritional value and may also increase consumer demand and open new market niches for mushroom growers. Appropriate power parameters including voltage, power (kW), energy (kWh), and power factor were recorded and analyzed. Each of these power parameters may influence a mushroom producer's electricity expenses, depending on the utility company and the particular tariff. An economic analysis was performed to establish the costs associated with various strategies for controlling the process. Developed analytical procedure to evaluate the expected benefits to purchase generated electricity from a private vendor compared to getting the bundle of electricity services from the local assigned utility company. Developed and conducted numerous educational programs to convey the various options for purchasing electricity and increasing energy efficiency. Monitored electricity usage to evaluate various alternatives for controlling ventilation rates during Phase I composting.

Impacts
This project has a major impact on resolving cultural benchmarks growers will need to optimize their investments in Phase I aerated composting systems and evaluate management schemes for maximum yield, quality and energy savings. The results of this project show that aeration does, in fact, reduce the amount of the indicator chemicals and provides some guidelines for modifying or constructing an economically feasible substrate preparation facility. It has integrated established and new management methodologies with new odor measurement technologies. It has provided the technology transfer through extension outreach needed to educate growers in approaches to controlled environmental composting. Reduction of odors from Phase 1 and spent substrate processing will improve relations between the operations and the community. Results of the value added research will enable growers to promote the health benefits of consuming fresh mushrooms and will have an impact on improving the market demand. It is anticipated that mushroom producers will be able to use the results of the energy analyses to make decisions at least on a daily basis concerning how the electricity demand will be managed for the day based on the analyses of how electricity was used in the previous day and the predicted weather forecasts. These and other outcomes of the project have enabled mushroom farmers to continue to be productive and remain competitive in the North American market.

Publications

• Sabeh, N., Wheeler, E. F., Beyer, D.M. and Heinemann, P.H. 2005. Environmental control strategies in Agaricus bisporus production rooms and their effects on mushroom quality. Mushroom News, Science and Technology 53(1):6-12.
• Chikthimmah, N., LaBorde, L. F. and Beelman, R. B. 2005. Hydrogen peroxide and calcium chloride added to irrigation water as a strategy to reduce bacterial population and improve quality of fresh mushrooms. Journal of Food Science. 70(6):273-278.
• Beelman, R. B. and Royse, D. J. 2005. Evaluation of Orykta(TM) as a source of micronutrients to improve yield and quality of Agaricus bisporus mushrooms. In: Tan et al. (eds.). Proceedings of The 5th International Conference on Mushroom Biology and Mushroom Products. April 8-12, 2005, Shanghai, China. Acta Edulis Fungi Vol. 12 (Supplement) Pp. 277-281.
• Collopy, P. D., and Royse, D. J. 2004. Characterization of phytase activity from cultivated edible mushrooms and their production substrates. J. Agr. Food Chem. 52:7518-7524.

Progress 01/01/04 to 12/31/04

Outputs
Phase I aerated floor bunker data collection at the Mushroom Test Demonstration Facility (MTDF). Completed experiments compared changes in composting dry matter, oxygen, temperature and moisture content of standard windrow mushroom composting with that of forced aerated composting. Continuous monitoring system for specific odor compounds is being used to determine what influence compost moisture and aeration has on the odor chemical components. The project is evaluating different aeration management schemes to determine if intermittent or continuous aeration has any impact on mushroom composting or fresh mushroom yields or quality. Odors produced at different composting temperatures are being investigated to determine when composters should be aware of potential movement of odors and when maximum aeration is needed. Alternative production practices for Agaricus bisporus were investigated. Growth of Agaricus bisporus mushrooms on hydroponic media was demonstrated to be feasible, but yields were much smaller than conventional substrate. Dextrose solutions yielded higher than sucrose solutions. Millet grain as a substrate provided yields similar to conventional substrate, particularly when a supplement was used. Simulation models were developed to study the behavior of Phase I substrate under aerated conditions. Models were validated with observations from aerated floor facilities.

Impacts
This project has a major impact on resolving cultural benchmarks growers will need to optimize their investments in Phase I aerated composting systems and evaluate management schemes for maximum yield, quality and energy savings. It would integrate established and new management methodologies with new odor measurement technologies. In addition, it will provide the technology transfer through extension outreach needed to educate growers in approaches to controlled environmental composting. By understanding, aeration restrictions for composting will help growers to better manage their operation, which will in turn reduce processing time, reduce energy usage, and improve mushroom yield and quality. Reduction of odors from phase 1 and spent substrate processing will improve relations between the operations and the community. An alternative to traditional compost for growing mushrooms would have a large positive impact on the environment and surrounding neighbors. Alternative substrates for Agaricus bisporus growth will help the mushroom industry reduce the negative impacts of Phase I processing on neighbors and the environment. The alternative substrates also provide a means for growing mushrooms for pharmaceutical use, where reduced yields are not necessarily a negative factor. Models for aerated floor facilities can help with efficient management of Phase I processing.

Publications

• Bechara, M. A., Heinemann, P.H., Walker, P.N., Romaine, C.P. and Heuser, C.W. 2004. Novel methods of cultivating Agaricus bisporus. ASAE Paper No. 04-7001. American Society of Agricultural Engineers. St. Joseph, MI. 12 pp.
• Holcomb, E.J., Heuser, C.W. and Heinemann, P.H. 2004. Nitrogen and potassium nutrition of geraniums grown in spent mushroom substrate (SMS) fertilized with leachate from SMS. Combined Proceedings International Propagator's Society. 53:142-145.
• Heinemann, P.H., Labance, S.E., Walker, S. and Beyer, D.M. 2004. Modeling mushroom substrate temperature during aerated phase I substrate preparation. Transactions ASAE. 47(4):1301-1311.
• Royse, D.J., Ohga, S. and Sanchez-Vazquez, J.E. 2004. Yield, mushroom size and time to production of Pleurotus cornucopiae (oyster mushroom) grown on switch grass substrate spawned and supplemented at various rates. Bioresource Technol. 91:85-91.
• Geml, J., Geiser, D.M. and Royse, D.J. 2004. Molecular evolution of Agaricus species based on ITS and LSU rDNA sequences. Mycological Progress 3:157-176.
• Shen, Q., Tan, Q. and Royse, D.J. 2004. Growing Lentinula edodes and other mushrooms in China--a low input technology alternative. Revista Mexicana de Micologia 18:15-20.
• Romaine, C.P., Keil, C.B., Rinker L. and Royse, D.J. (Eds.). 2004. Science and Cultivation of Edible and Medicinal Fungi. Mushroom Science, Vol. 16. The Pennsylvania State University Press, University Park, Pennsylvania, U.S.A. 733 pp.
• Royse, D.J., Beelman, R.B. and Weil, D.A. 2004. Manganese sulfate additions increase mushroom (Pleurotus cornucopiae) yield in delayed release nutrient-supplemented cottonseed hull/wheat straw substrate. IN Science and Cultivation of Edible and Medicinal Fungi. Mushroom Science, Vol. 16. Romaine, C. P., C. B. Keil, D. L. Rinker and D. J. Royse, eds. The Pennsylvania State University Press, University Park, Pennsylvania, U.S.A. pp. 359-364.
• Ohga, S., Cho, N.S., Li, Y. and Royse, D.J. 2004. Utilization of pulsed power to stimulate fruitification of edible mushrooms. IN Science and Cultivation of Edible and Medicinal Fungi. Mushroom Science, Vol. 16. Romaine, C. P., C. B. Keil, D. L. Rinker and D. J. Royse, eds. The Pennsylvania State University Press, University Park, Pennsylvania, U.S.A. pp. 343-351.
• Geml, J., Geiser, D.M. and Royse, D.J. 2004. Molecular phylogeny of Agaricus species. Pages 165-173. IN Science and Cultivation of Edible and Medicinal Fungi. Mushroom Science, Vol. 16. Romaine, C. P., C. B. Keil, D. L. Rinker, and D. J. Royse, eds. The Pennsylvania State University Press, University Park, Pennsylvania, U.S.A. pp. 165-173.
• Beelman, R.B., Royse, D.J. and Chikthimmah, N. 2004. Comparison of nutritional components between button, shiitake and oyster mushrooms. Mush. News 52(2):12-23.
• Beelman, R.B., Royse, D.J and Chikthimmah, N. 2004. Bioactive components in Agaricus bisporus (J. Lge) Imbach of nutritional, medicinal, or biological importance. IN Science and Cultivation of Edible and Medicinal Fungi. Romaine, C. P., C. B. Keil, D. L. Rinker and D. J. Royse, eds. Mushroom Science, Vol. 16. The Pennsylvania State University Press, University Park, Pennsylvania, U.S.A. pp. 1-16.
• Coutino, F., Jimenez, L., Sanchez, J.E. and Royse. D.J 2004. Digitaria decambens grass substrate prepared by alkaline immersion for culture of Pleurotus spp. IN Science and Cultivation of Edible and Medicinal Fungi. Romaine, C. P., C. B. Keil, D. L. Rinker and D. J. Royse, eds. Mushroom Science, Vol. 16. The Pennsylvania State University Press, University Park, Pennsylvania, U.S.A. pp. 267-271.
• Royse, D. J. 2003. Fungi. IN Encyclopedia of Food and Culture. S. H. Katz, ed. Charles Scribner's Sons Reference Books, NY. Vol. 2:84-90.

Progress 01/01/03 to 12/31/03

Outputs
Phase I aerated floor bunker data collection continued into early 2003 at the Mushroom Test Demonstration Facility (MTDF). Completed experiments compared changes in composting dry matter, oxygen, temperature and moisture content of standard windrow mushroom composting with that of forced aerated composting. Compost procedures were altered to determine how higher compost moisture would perform using forced aeration. The project is evaluating different aeration management schemes to determine if intermittent or continuous aeration has any impact on mushroom composting or fresh mushroom yields or quality. Odors produced at different composting temperatures are being investigated to determine when composters should be aware of potential movement of odors and when maximum aeration is needed. The data were used to validate a compost temperature prediction models based on various aeration schemes. A project to investigate the utilization of hydroponics for Agaricus production was initiated in 2003. Vermiculite, perlite, and other inorganic substrates were used for providing structure to the mycelium. Variations on nutrient-rich liquid media have been investigated for maximum mushroom production. Contamination and low yields have been challenges in the early efforts of this work. Specifications were developed to purchase a power data logger to record and analyze all major power parameters associated with the use of the two 5-hp fans used in the bunker composting. A protocol was developed for recording and analyzing the appropriate power parameters including voltage, power (kW), energy (kWh), and power factor. Each of these power parameters may influence a mushroom producer's electricity expenses, depending on the utility company and the particular tariff. In the PECO (Philadelphia Electric Company) territory, each of the selected power parameters influences the utility bill for the producers on industrial and commercial rate tariffs. After the relationships are established, then economic analyses will be performed to establish the costs associated with various strategies for controlling the process. The ultimate comparison will be when the mushroom yield from the various composting strategies will be compared to the costs of operating the fans. Additional research was conducted to determine whether current composting formulations provided sufficient levels of micronutrients in the substrate to obtain optimal yield potentials. Results suggested that the supply of micronutrients in compost might sometimes be inadequate to support optimum crop yields. The results from this research indicated that manganese appeared to be the primary micronutrient responsible for producing a stimulatory effect on yields.

Impacts
This project has a major impact on resolving cultural benchmarks growers will need to optimize their investments in Phase I aerated composting systems and evaluate management schemes for maximum yield, quality and energy savings. It would integrate established and new management methodologies with new odor measurement technologies. In addition, it will provide the technology transfer through extension outreach needed to educate growers in approaches to controlled environmental composting. By understanding, aeration restrictions for composting will help growers to better manage their operation, which will in turn reduce processing time, reduce energy usage, and improve mushroom yield and quality. Reduction of odors from phase 1 and spent substrate processing will improve relations between the operations and the community. An alternative to traditional compost for growing mushrooms would have a large positive impact on the environment and surrounding neighbors. If successful, this approach would eliminate run-off and odors from substrate processing, and would eliminate the large spent mushroom substrate disposal issues. It also will encompass the concept of labor saving technology that will be a part of the Pennsylvania mushroom industry in the near future. It is anticipated that mushroom producers will be able to use the results of the analyses to make decisions at least on a daily basis concerning how the electricity demand will be managed for the day based on the analyses of how electricity was used in the previous day and the predicted weather forecasts.

Publications

• Beyer, D. M. 2003. Basic procedures for Agaricus mushrooms growing. Pennsylvania State University, University Park, PA. 16 pp.
• Beyer, D. M. and Kremser, J. J. 2003. Efficacy of fungicides against Verticillium and Trichoderma pathogens of Agaricus bisporus. In 8th International Congress Plant Pathology Proceedings, Christchurch, NZ. Vol. 2:66.
• Buffington, D.E. 2003. Understanding your monthly electricity bill. Mushroom News 51(1):18-20.
• Buffington, D. E. 2003. How much does an extra kilowatt-hour of electricity cost. Mushroom News 51(3):14-15.
• Buffington, D. E. 2003. Data-mining your energy bills. Mushroom News 51(10):12-15.
• Chen, X., Ospina-Giraldo, M. D., Wilkinson, V., Royse, D. J. and Romaine, C. P. 2003. Resistance of pre- and post-epidemic strains of Agaricus bisporus to Trichoderma aggressivum f. aggressivum. Plant Dis. 87:1457-1461.
• Heinemann, P. H., Graves, R. E., Walker, S., Beyer, D. M., Holcomb, E. J., Heuser, C. H., Preti, G., Wysocki, C. and Miller, F. 2003. In-vessel processing of spent mushroom substrate for odor control and reduced processing time. Applied Engineering in Agriculture. 19(4):461-471.
• Ivors, K. and Beyer, D. M. 2003. Microbiology of mushroom substrate. Mushroom News 51(8):6-16.
• Royse, D. J., and J. E. Sanchez-Vazquez. 2003. Influence of precipitated calcium carbonate (CaCO3) on shiitake (Lentinula edodes) yield and mushroom size. Bioresource Technol. 90:225-228.
• Beelman, R. B., D. J. Royse and N. Chikthimmah. 2003. Bioactive components in Agaricus bisporus (J. Lge) Imbach (Agaricomycetideae) of nutritional, medicinal, and biological importance (Review). Internat. J. Med. Mush. 5:321-337.
• Royse, D. J. 2003. Cultivation of oyster mushrooms. College of Agricultural Sciences, Pennsylvania State University, University Park, PA. 12 pp.
• Royse, D. J. and Romaine, C. P. 2003. Evaluation of fungicide applications on spawn for control of mushroom green mold, 2002. Fungicide and Nematicide Tests 58:V069.
• Williams, A. L., Heinemann, P. H., Graves, R. G., Beyer, D. M., Wysocki, C. and Roush, W. B. 2003. Classification of mushroom substrate odors using a portable electronic nose and neural networks. ASAE Paper No. 03-4104. American Society of Agricultural Engineers. St. Joseph, MI. 15 pp.

Progress 01/01/02 to 12/31/02

Outputs
Experiments were carried out to compare changes in composting dry matter, oxygen, temperature, gypsum and moisture content of standard windrow mushroom composting with that of forced aerated composting. Odors produced from different compost formulae showed higher quantities of gypsum did not increase the intensity or reduce pleasantness of the odors produced. The different moisture and aerated composts showed no significant difference in yield by break and total yield. Aeration or compost moisture did not influence fresh mushroom solids, initial whiteness or color. The aeration energy balance model was verified and tested using measurements taken at the Mushroom Test Demonstration Facility (MTDF). Aerations of different cycle lengths were run, including four minute, ten minute, and variable aeration cycles. Statistical tests show that the model substrate temperature predictions and the observed substrate temperature were very closely correlated and the differences were within acceptable limits. Various energy strategies are being explored to optimize the use of energy with the objective of increasing profitability of mushroom production. Major emphasis focused on measuring energy use by fans for continuous use versus intermittent use. Other emphasis focused on the importance of documenting detailed energy usage and managing energy demand. Spent mushroom substrate odor reduction trials have shown conclusively that odors are reduced by aeration. Synthetic Lentinula edodes logs were vacuum-soaked or regular-soaked to determine the effects of soaking on yield and mushroom size, log weight variability, and water distribution within the log. Vacuum-soaked log weights had lower standard deviations than weights for regular-soaked logs in 4 out of 6 soaks indicating a more uniform soak process. Continued research involving the incorporation of varying levels of a micronutrient rich additive to the compost at casing (Micromax, Scotts-Sierra Horticulture Products Co., Marysville, OH) was conducted utilizing two crops at the MTDF. It appears that the addition of Micromax at casing predominately impacts the first flush. Most of the observed yield increases and color improvements occurred during the first flush. On average, the addition of 0.5% Micromax (on a dry weight basis relative to the compost) increased yields by approximately 5.0% compared to the control, with cumulative percent yield increases ranging from +12.4 to +1.3. This supports the concept that a deficiency of micronutrients is present in current substrates. Crops at the MTDF were utilized to investigate the effects of Micromax added to the compost at spawning, on mushroom crop yield and quality. No impact was observed on yield however, significant improvements were observed for the whiteness of the mushrooms as a result of adding Micromax to the compost during the first flush.

Impacts
Better understanding of the aerated phase 1 substrate preparation process will help growers to better manage their operation, which will in turn reduce processing time, reduce energy usage, and improve mushroom yield and quality. Reduction of odors from phase 1 and spent substrate processing will improve relations between the operations and the community. The principal merit of our research is the noticeable increase in mushroom yield when synthetic logs are vacuum-soaked. While growers may be able to substantially increase yield with vacuum soaking, size may decrease appreciably. This may adversely affect the prices growers receive for their product so they should weigh the relative merits of increased yields at the potential expense of reduced mushroom size. Reducing the consumption of energy and improving the efficiency of the composted substrate

Publications

• Buffington, D.E. 2002. Increasing profitability of mushroom production. Mushroom School Journal (Russian). 2 pp.
• Heinemann, P.H., Walker, S.P. and Labance, S.E. 2002. Modeling mushroom substrate temperature during aerated phase I substrate preparation. ASAE paper no. NABEC 02-037. The American Society of Agricultural Engineers. St. Joseph, MI. 14 pp.
• Beyer, D. M., Beelman, R.B., Kremser, J.J. and Rhodes, T. 2002. Casing additives and their influence on yield and fresh quality of Agaricus bisporus. IN Proceedings of the 4th International Conference on Mushroom Biology and Mushroom Products, Cuernavaca, Mexico. Sanchez, J. E. et al. ,eds. February 20-23, 2002. pp. 145-152.
• Beyer, D.M., Beelman, R.B., Heinemann, P., Lomax, K.M., Rhodes, T.W., Kremser, J.J. and Wysocki, C. 2002. Influence of Forced Air, Compost Moisture and Gypsum on Mushroom Composting, Odors, Yield and Fresh Quality. Proceedings of the International Symposium on Composting and Compost Utilization. May 2002. Columbus, Ohio. pp.878-891
• Buffington, D.E. 2002. Energy strategies to increase profitability. Mushroom News 50(1):4-7.

Progress 01/01/01 to 12/31/01

Outputs
The preliminary research that involves aerated Phase I composting and the reduced in odors and improving management was started at the MTDF. Compost moisture was maximized and it was shown that it was difficult to over water compost in an aerated bunker, however odors appeared to increase with compost moisture. Preliminary research involving the incorporation of varying levels of a micronutrient rich additive to the compost at casing (Micromax, Scotts-Sierra Horticulture Products Co., Marysville, OH) was conducted utilizing four crops at the MTDF. The results from these crops seem to indicate an increasing yield trend corresponding to increasing quantities of Micromax added. This supports the concept that a deficiency of micronutrients is present in current substrates. Furthermore, boron appeared to be the only micronutrient to display an increased uptake by the mushroom as the concentrations in the substrate increased. To further investigate the effect of boron availability on the quality and yield of mushrooms, boron was introduced to the mushrooms in form of boric acid added to the irrigation water for four crops at the MTDF. No clear trends regarding changes in yields or mushroom quality are evident. However, the addition of boric acid to the irrigation water treatments significantly increased the boron content of the mushrooms, in three flushes, when compared to a control. Aerated floor bunkers for phase I mushroom substrate processing were analyzed both theoretically and empirically. Short aeration duration throughout processing (i.e. 1-3 minutes) did not provide sufficient oxygen for proper biochemical activity resulting in inadequate processing. Longer aeration durations (5-10 minutes) provided adequate oxygen but after the initial 24-hour heat up period, were more than necessary. An optimal aeration scheme has been recommended. Aeration of spent mushroom substrate has been shown to significantly reduce odors as determined by human olfactometric evaluation. It has also been shown to reduce processing time by 2-4 weeks.

Impacts
Information generated from this project has improved the growers understanding how composting odors can be reduced. More research has been completed for the control of Trichoderma green mold disease. In addition, value added elements have been shown to improve mushroom's marketing options and sales. The use of aeration to improve the disposal of spent mushroom substrate was demonstrated at the Mushroom Test Demonstration Facility.

Publications

• Anderson, M. G., Beyer, D. M. and Wuest, P. J. 2001. Yield comparison of hybrid Agaricus mushroom strains for resistance to Trichoderma green mold. Plant Disease 85:731-734. (3,6 20 pct )
• Werner, A. W. and Beelman, R. B. 2001. Growing high-selenium edible and medicinal button mushroom (Agaricus bisporus (J. Lge) Imbach) as ingredients for functional foods or dietary supplements. Int. J. Med. Mush. 4 (2):194-210.
• Heinemann, P. H., Graves, R. E. Walker, S. P. Holcomb, E.J., Heuser, C., Beyer, D. M. Preti, G., Wysocki, C. J. and Miller, F. C. 2001. Aerated Floors for spent mushroom substrate processing. ASAE paper no. NABEC 01-902. The American Society of Agricultural Engineers. St. Joseph, MI. 18 pp.
• Sabeh, N., Wheeler, E. F., Heinemann, P.H. and Beyer, D. M. 2001. Improving Agaricus bisporus mushroom quality through improved air distribution methods. ASAE Paper No. 01-4088. American Society of Agricultural Engineers. St. Joseph, MI. 17 pp.

Progress 01/01/00 to 12/31/00

Outputs
Micro-silos were designed and built to study the effects of phase I compost formulation on odor production and mushroom yield. Three different poultry manure levels (zero poultry, standard poultry, double poultry) were used in compost formulations to determine if poultry manure influenced odor production. Air samples were taken for odor measurements and assessed by by a trained odor panel for odor intensity and pleasantness ratings. The compost containing the highest amount of poultry manure had an overall significantly higher odor intensity rating than the zero poultry manure formula. The compost containing the high poultry manure levels also had a significantly higher overall odor unpleasantness rating than both the zero and the standard poultry manure formulas. Several silage grinders were tested to determine how a complete mix of bulk ingredients, water and supplements would influence Phase I mushroom composting. A two-day workshop was given to examine the developing technology of aerated Phase I composting for mushroom production in Pennsylvania and at the MTDF. The objective of the workshop was to exchange concepts and actual experiences on aerating compost to reduce odors during the composting process. Use of aerated floor bunkers are also being studied in the processing of spent mushroom substrate. Results indicate that plants grown in growing media mixed with substrate processed by aeration compare favorably with similar mixes using substrate composted in windrows. We have identified more than 100 microorganisms, including both bacteria and fungi, in a Phase II mushroom compost sample using the sequence of genes encoding small subunit ribosomal RNA as a molecular tag. In contrast to the highly diverse bacterial community structure, the fungal community in Phase II compost appears quite simple, mainly consisting of Scytalidium spp. We are currently surveying the diversity of microorganisms in compost during various stages of composting and mushroom production. We also plan to compare the structure of microbial communities between aerated and non-aerated composts. A soy-based selenium-enriched compost supplement, containing 40 ppm selenium, was applied to the compost during spawning in four crops grown in trays at the MTDF. The selenium concentration in the compost in treated trays was 1 ppm, dry weight. The selenium concentration in the untreated supplement was below the detectable limit of 0.05 ppm, which resulted in a selenium concentration in the compost of <0.05 ppm, dry weight compost. The application of the selenium-enriched supplement produced mushrooms that contained approximately 61% of the RDA of selenium in one serving of fresh mushrooms, with a range among flushes of 49-74%. The selenium addition had no significant effect on crop yield or quality of the mushrooms.

Impacts
Researchers have the options of adjusting bulk densities and moisture content, mixing timing and other parameters to determine optimum Phase I bunker composting methodology using the recommended mixer tested. A better understanding of how the compost microbial communities change, and how these changes influence various aspects of mushroom production will open up the possibility of targeted manipulation of specific organisms during different phases of mushroom production. Such manipulation could be used to alleviate composting odors, to better manage mushroom disease epidemics, and to increase available nutrients and mushroom fruitification. These results indicated that the cultural practices used in this study can be adapted by commercial growers to produce high-quality, selenium-rich mushrooms with minimal cost or change in standard practices. Such commercially produced selenium-rich mushrooms, with selenium concentrations high enough to bear the FDA-approved label claiming 'an excellent source of selenium,' could capitalize on consumers' desires to include more fresh produce in their diets and to positively influence their health through nutrition.

Publications

• Pecchia, J. A., Beyer, D. M. and Wuest, P.J. November 2000. A study on Phase I compost management and odor production. Mushroom News 11(9). 16-23.
• Pecchia, J.A., Beyer, D.M. and Wuest, P.J. 2000. The effects of formulation and compost temperature on odor generation in phase I mushroom composting. IN Mushroom Science XV, Science and Cultivation of Edible Fungi. Van Griensven, ed. Balkema Rotterdam. pp. 335-339.
• Pecchia, J.A. 2000. The influence of formulation and temperature regimes on mushroom composting odor generation and mushroom yield. Ph.D. Thesis. The Pennsylvania State University, University Park, PA. 92 pp.
• Ivors, K. L., Collopy, P. D., Beyer, D. M., and Kang, S. 2000. Identification of bacterial microorganisms in mushroom compost using ribosomal RNA sequence. Comp. Sci. Util. 8(3):247-253.
• Ivors, K. L., Beyer, D. M. and Kang, S. 2000. Investigating the microbial diversity of commercial mushroom substrate using molecular techniques. IN Mushroom Science XV, Science and Cultivation of Edible Fungi. Van Griensven, ed. Balkema Rotterdam. pp. 401-407.
• Ivors, K. L., Beyer, D. M., and Kang, S. 2000. Identification of microorganisms in mushroom compost using ribosomal RNA sequence. IN Proceedings of the International Composting Symposium. P.R. Warman and B.R. Taylor, eds. CBA Press, Truro, Nova Scotia. pp. 493-506.
• Ivors, K., Beyer, D., Wuest, P., and Kang, S. 2000. Survey of fungal flora in mushroom compost using ribosomal RNA sequence. (Abstract) Phytopathology 90:S38.
• Ivors, K., Beyer, D., Wuest, P., and Kang, S. 2000. Survey of microbial diversity within mushroom substrate using molecular techniques. IN Science and Cultivation of Edible Fungi, Proceedings of the 15th International Congress. L. van Griensven, ed. Balkema, Rotterdam. pp. 401-407.