Washington State University
Center for Sustaining Agriculture and Natural ResourcesThe Compost Connection
for Western Agriculture
July 1999
Funded by a grant from the western region USDA-SARE ProgramNo. 10
Compost Effects on Apple
Tree Growth
by David Granatstein and Patty Dauer
Tree fruit production is a major agricultural activity in Washington State, covering over 200,000 acres. Many orchards have coarse-textured soils or soils with unique challenges, including apple replant disease. Increasingly, growers have turned to compost to address these problems, and with the increasing acreage of fruit in certified organic production, compost is being more widely used. We began a series of on-farm tests several years ago to see whether we could develop some guidelines for compost use in orchards. Growers generally report favorable results but there has been no work done to establish optimum rates or compare the effects of different types of compost. And with the shorter life of orchards with new varieties, getting a fruit tree off to a good start from day one is vital economically. We worked with 14 different orchards over three years. They can be grouped as to three situations: a new planting on soil that had never been in orchard; a new planting on former orchard soil; and an existing planting that was growing poorly. In addition, we tested compost in one trial where new trees were interplanted into an existing orchard. Eleven orchard trials were monitored in 1998: 3 were orchards replanted in 1998, 3 were orchards replanted in 1996 or 1997 and monitored from planting, 1 was a 1997 interplant monitored from planting, 3 were new plantings monitored from planting in 1996, and 1 was an existing orchard monitored from 1996.
Treatments within the trials varied, but all included a control and at least one compost application.
(go to p. 2, APPLE)
Composting Dairy Cow
Mortalities in Utah
by David Granatstein
Most backyard composting guides suggest that no meat scraps be put into the compost heap. Yet farmers across the country are experiencing great results using composting to dispose of animal mortalities on the farm. Several researchers at Utah State University in Logan, Utah, recently completed a study to test the feasibility of composting dairy cow mortalities under the climatic conditions of the Intermountain West. The researchers, Penny Trinca, Bruce Miller, and Richard Beard hoped to establish composting as a cost effective and environmentally sound alternative to the currently approved methods of animal carcass disposal in Utah: burying, rendering, landfilling, or incineration.
The dairy industry is concentrated in northern Utah, with nearly 20,000 adult cows. Local dairy
managers estimate that with a well-managed herd, there will be from 1 to 7 mortalities of cows or calves per year. The collective number of mortalities could total several thousand carcasses per year.
Methods
The study had four objectives: adapt animal carcass composting procedures from other regions to Utah conditions; compare the results from two readily available co-compost materials (wheat straw and softwood sawdust); evaluate potential environmental contamination; and characterize the finished product and its potential use. (go to p. 4, COW)
Inside This Issue
• Soils for Salmon …p. 2
• Vermicomposting food waste … p. 6 • Zeolites and compost …p. 7
• Summer Tours
Evaluation Form
Evaluation Form
Enclosed
Soils for Salmon: The Urban
Environment by Andy Bary
With the listing of the Chinook salmon by the National Marine Fisheries Service as endangered, the protection of salmon habitat has become increasingly important in urban Puget Sound. The Washington Organic Recycling Council (WORC) led a seminar addressing some of the issues surrounding the relationship between urban soils and salmon habitat. The seminar was attended by 200 professionals who work in the areas of urban planning, landscape design, soil conservation and landscape maintenance. Other semiar sponsors included Washington Sate University – Puyallup, and the University of Washington Center for Streamside Studies and Center for Urban Water Resources Management. Seminar participants discussed some of the issues surrounding soils and urban development. This included the basics of soil science, amending disturbed soils with compost, turf management, alternative site design, and differences in water movement in forested sites as compared to developed sites. Differing views were presented on how the density of housing can potentially affect salmon habitat in the Puget sound.
The theme that tied the seminar together was how to better manage urban soils to reduce impacts on the salmon habitat. Construction of new housing in the Puget Sound area can lead to salmon habitat degradation. During development, native vegetation is removed, changing the amount, timing and quality of water entering streams. This can be somewhat improved during site development by minimizing the removal of native topsoil, limiting removal of native vegetation, reducing the amount of compaction by heavy equipment and amending soils with compost
prior to landscape development. The addition of compost into the soil can improve water storage, nutrient availability and soil structure. These changes in soils can lead to better turf and
ornamental plant growth, and a reduction in runoff that benefits salmon habitat.
The city of Redmond has led the way by developing a 60-page guideline that discusses landscaping with compost amended soils. To receive a hardcopy of the guidelines and a special newsletter summarizing the first Soils for Salmon seminar, send $10 to Soils for Salmon, WORC, P.O. Box 7514, Olympia, WA 98507. The guidelines are also available at the Center for Urban Water Resources Management web site: http://weber.u.washington.edu/~cuwrm/
Another seminar is being planned for fall 1999 in Tacoma, WA. If you wish more information on this seminar, contact WORC at 360-754-5162 or email at [email protected].
Andy Bary is a Scientific Assistant, Washington State University, Puyallup, WA.
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(from p. 1, APPLE)
We measured tree growth by the change in trunk cross-sectional area (TCSA), a good indicator of overall tree growth. We also measured shoot extension in some trials. On bearing trees, we measured fruit yield and size when possible. In past years, we did leaf analysis for total N, and a limited amount of soil moisture monitoring. Each trial was statistically analyzed separately. In most cases, there were no significant differences among treatments. The data were also pooled to develop regression lines of compost rate versus tree growth (see Figure 1) There are many composts from which to choose. Although differences within and between kinds of compost, i.e. animal waste composts and yard waste composts can be significant, to date we have not determined that significant differences exist in regard to their effect upon tree growth. The kind of compost used by an orchardist will depend upon what he or she intends the compost to do: fertilize, mulch, or improve physical soil properties. An accurate lab
analysis from the compost supplier is very useful in determining if a particular compost meets those needs.
Another big variable in comparing the on-farm trials has been soil variability between farms and within the individual blocks. More often than not, the compost trial results have unintentionally provided a means of mapping the soils within an orchard and identifying problem areas by virtue of the replications in the experiment.
Results and Discussion
Interplant. At one site, new trees were interplanted into a young planting where some trees had failed. Treatments included various composts and rates, as well as leonardite, that were added to the planting holes. Trunk growth increases (TCSA) ranged from 21 - 33% during the first year and 64 - 88% during the second year. The first year growth was much lower than desirable. No significant treatment differences were seen.
Established Orchards. Revitalizing a poorly
growing existing orchard is difficult. If the condition causing stress is soil related, amendments can help. In comparing stressed trees to healthy trees however, the stressed trees never "catch up". Amendments work slowly and can not be viewed as a quick fix. The three orchards where compost additions have been tried show this to be true. Two orchard compost trials (evaluated in 1996 and 1997) were located within poor soil inclusions, with the remainder of the orchard growing well.
Evaluation continued in 1998 at one orchard site with under-performing trees. Compost topdressing was applied with shovels or buckets in both 1996 and 1997. Chicken, yard waste, and dairy composts were applied. Rates varied from 0 - 34 lb/tree. The
percent increase in trunk cross-sectional area (TCSA) for 3 years was calculated and used as the main index of comparing tree growth. Size and number of fruit were also recorded when possible (Table 1).
Table 1. Effect of Compost Topdressing on Apple Tree Growth and Yield (Fuji/M26, 5 yr. Old in 1996)
Fruit Fruit Fruit/ - - - -% Increase in TCSA - - - count/ weight tree Treatment 1996 1997 1998 3 yr total tree (lb) (lb) Chicken/Dairy, 9-12 lb. 15 16 11 47 63 0.66 42 Chicken/Dairy, 18-24 lb. 12 17 14 49 63 0.65 41 Yard waste, 15-17 lb. 17 16 8 44 66 0.61 40 Yard waste, 30-34 lb. 17 13 18 60 71 0.61 43 Chicken - high N, 11 lb. 10 5 17 32 55 0.64 35 Chicken - high N, 22 lb. 11 15 4 33 58 0.64 37 Check 15 15 14 53 69 0.60 42
None of the compost treatments performed better than the check. There are no differences statistically. The small increases in TCSA are typical for more mature bearing tress, and changes in fruit yield become the more important indicator.
Replant Orchards. Most apple orchards in Washington experience replant problems when orchard renewal occurs. This is primarily due to soil-borne pathogens (fungi, nematodes) and
degraded soil structure. A few growers have used compost in hopes of a disease suppressive effect. Others use it after soil fumigation to try to
reinolculate the soil with beneficial organisms. We tested various types of compost on six replanted orchards. Several rates were used and the compost was incorporated in one of two ways: banded and tilled into the tree row before planting; or mixed with soil as the planting hole was being filled. In most individual trials, there were no significant treatment
differences. When looking at the data across sites and years (Figure 1), a regression line of compost rate versus trunk growth does show a significant positive slope. But the R2 value is quite low and thus other factors in addition to compost are contributing
to the growth increase. When separated by year (data not shown), the biggest growth increase occurs in Year 2 (average around 100%), while both Year 1 and 3 tend to average around 50%.
Figure 1. Effect of Compost on Cumulative (3-year) Increase in Apple Tree TCSA on Replant Sites.
This is the first of a two-part series. The second half will be presented in the next newsletter issue.
David Granatstein is Sustainable Agriculture Coordinator, and Patty Dauer is Project Assistant, at Washington State University, Wenatchee, WA. This research was conducted as part of a
cooperative effort between WSU and The Food Alliance. Funding for this project came from a grant from the W.K. Kellogg Foundation Integrated Farming Systems program.
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(from p. 1, COW)
The study was conducted in Logan, Utah, utilizing adult Holstein dairy cows. Ten compost “plots” were set up, with five using straw and five using sawdust. A plastic liner under each plot collected any leachate. Piles were constructed by spreading an 18-24” layer of straw or sawdust prior to carcass placement. After placement, more straw or sawdust was added on top and was watered to wet it to about 60%
moisture. The carcass weights ranged from 1,100 to 1,200 pounds.
For the sawdust plots, 4 bucket loads were added before the carcass and 5 buckets after. For straw, 3 bales went on before the carcass, and 5 bales after. About 14 gallons of water were added to the straw piles and 60-70 gallons to the sawdust piles. The goal was to wet the co-composting material down to the carcass but not below it so the bedding
underneath could absorb moisture coming from the decomposing carcass.
The researchers monitored pile moisture content and temperature, leachate, and stage of decomposition by opening the piles for visual inspection.
Results
All piles reached peak temperatures within about two weeks. The peak for sawdust was near 60oC
(140oF), and 49oC (120oF) for straw. The piles maintained maximum temperatures for about four weeks and then declined steadily. Only the sawdust 0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0 6 0 0 7 0 0 0 2 0 4 0 6 0 8 0 C o m p o s t R a t e ( l b / t r e e ) % increase in TCSA p=0.01 R2=0.42
piles experience a second temperature spike after re-aeration. Sawdust piles were consistently hotter than straw piles and cooled more slowly.
Leachate was collected from every pile. Straw piles averaged 12.5 gallons per pile (range 8-23 gallons) and sawdust piles averaged 20.7 gallons per pile (range 14-37 gallons). The sawdust piles leached about 40% more than the straw piles. Odor was not quantitatively measured, but the researchers observed more odors from the straw than the sawdust, which is consistent with experience from other parts of the country.
The piles were opened at 135 days and 160 days after initiation to examine the degree of decomposition. At 135 days, decomposition was more advanced in straw piles, with mostly bones and some hide remaining.
By 160 days, only brittle bones remained in most straw piles, while some flesh remained in the sawdust piles. At 11 months, when the piles were land applied with a spreader, only small pieces of bone were evident.
The nutrient content of the finished compost was tested and compared to the initial co-composting materials (Table 1). The nitrogen level was enriched for both materials, and the electrical conductivity (E.C., a measure of salt content) increased as well. But with the C:N ratio above 30, the product will likely tie up nitrogen in the soil and require additional fertilizer N. The composting decreased the pH of the straw while increasing the pH of the sawdust. Both materials were suitable for land application in agriculture.
Table 1. Nutrient content of bedding materials and finished compost.
Straw Straw/carcass compost Sawdust Sawdust/carcass compost C:N ratio 114 34 378 46 N (%) 0.45 3.02 0.12 0.66 P (%) 0.02 0.50 0.01 0.08 K (%) 0.82 1.31 0.12 0.13 Ca (%) 0.21 1.02 0.25 1.27 S (%) 0.06 0.38 0.01 0.07 E.C. (dS/m) 1.6 5.8 0.6 2.5 pH 7.6 6.6 5.7 6.4 Conclusions
The researchers believe that their study supports composting as a viable animal mortality disposal method. In this study, straw bedding appears less likely to leach fluids from a pile when compared to sawdust at the same moisture content. Straw piles lead to faster and more complete decomposition of the carcass, but may have more odors. However, sawdust piles have higher temperatures than straw. The EPA standard for pathogen reduction is 55oC, which is needed for certification of commercial compost. The sawdust piles exceeded this, while the straw piles did not.
A farm manager might choose the co-composting material based on availability and community constraints. If odor is a potential problem, use sawdust if possible. If not, less expensive straw may be the better choice. By increasing the depth of material under the carcass by another foot (at least 2.5 ft total depth), leachate from the piles should be eliminated. If the carcass is well hydrated at the time of incorporation, perhaps less or no water should be added.
The researchers are planning to meet with the state Dept. of Environmental Quality to request approval of composting as an animal mortality disposal practice. If approved, composting will need to prove
itself as a cost-competitive alternative, as it is unlikely that the compost itself would be a saleable product. Carcass composting would provide a farm with a usable by-product to help improve organic matter in soils.
Penny Trinca is a former graduate student at Utah State University and now works for the Utah
Association of Conservation Districts. Bruce Miller and Richard Beard are both faculty members in the Dept. of Agricultural Systems, Technology, and Education at Utah State University, Logan, UT.
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Worms Recycle Food Waste
at UC Extension
by Karin Grobe
A two year research project on food waste composting has been established at the Bay Area Research and Extension Center (BAREC) . Redworms will do the composting work with a technology called vermicomposting that is used extensively in countries like Australia and India. Redworms can consume up to half their weight in fruit and vegetable scraps each day. Worm castings, or vermicompost, is a fertilizer that is created when worms consume food wastes. It is rich in nutrients, microorganisms, enzymes and hormones that stimulate plant growth and promote healthy soil. The project will be implemented in two stages. The first step will be the establishment of the
vermicomposting beds in a BAREC greenhouse, and the second step the field production of peppers in soil amended with vermicompost. Vaishali Tamhankar, who is associated with the Institute of Natural Organic Agriculture (INORA) in India set up the vermicomposting beds in May 1999.
“Vermicomposting has proven to be an effective system for managing organic waste in India,” says Ms. Tamhankar. She has established worm composting systems that handle up to 11 tons of waste per day and has conducted training programs for Indian farmers.
The vermicomposting unit was established in two 20-foot nursery beds. First, a four-inch layer of moist hay was put in the beds. Next, a one-inch layer of compost from BFI Organics was applied. Then, 10 pounds of worms were distributed throughout the beds. The worms were covered with chopped up grocery store food waste which had been mixed with a small amount of horse manure. Everything was moistened, and a burlap cover was put over the beds. Food waste will be added once per week. The worms will compost one-half ton of vegetable and fruit waste per month and vermicompost will be harvested monthly.
Dr. Maria de la Fuente, Santa Clara County Farm Advisor, is excited about the project. “Vermicompost made on-farm in mid-scale vermicomposting systems may prove an economical input for small scale farmers,” she says. “Santa Clara County has many small farms growing vegetables, cut flowers and other high value crops. Results of this research project will be directly communicated to these farmers to help them to increase soil fertility, water holding capacity and reduce chemical use.
In the second stage of the research, Dr. de la Fuente will study the effect of the vermicompost on soil chemistry and biology. Vermicompost will be applied at different rates in plots that will be used to grow Cayenne chili peppers. The growth and health of the peppers will be compared to others that will be grown in soil amended with standard yard trimmings
compost and soil with no amendments.
The research is sponsored by the City of San Jose through its Agriculture in Partnership (AIP) program. Michele Young, City of San Jose Environmental Services representative explains. “If programs like this prove successful, San Jose can begin to recycle food waste from commercial and residential sources, eliminating these items from the landfill, while creating valuable compost.” Research is also supported by U.C. Cooperative Extension and the BAREC Research Center.
Karin Grobe is an independent compost consultant in Santa Cruz, CA.
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Zeolites Benefit Compost
Research at the Pacific Agri-Food Research Center (PARC) in Agassiz, British Columbia, has shown that the addition of zeolites can have beneficial effects on compost and the environment. During composting more than half of the nitrogen in poultry manure can be lost to the air as ammonia, becoming an air quality concern. The addition of zeolites reduces this ammonia loss.Adding zeolites during composting also conserves nitrogen which is adsorbed within the zeolite structure. When the compost is added to soil, the adsorbed nitrogen is released slowly and plants can take it up over a period of time. This reduces the risk of excessive nitrogen leaching to the groundwater when heavy rains come shortly after fertilizer or compost is applied.
Zeolites are a group of secondary minerals
characterized by their water content which is easily released with the application of heat. It has been found that some zeolites are more beneficial than others when added to compost.
Contact: Shabtai Bittman. Reprinted from the PARC Growing Ideas newsletter.
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Compost Resources
Olds College Composting Technology Centre has
two new manuals available through Compost in a Crate: "Leaf and Yard Waste Composting Manual" and "Mid-scale Composting Manual". They are available in hard copy from: Kelly MacKinnon, Olds College, Composting Technology Centre, 4500 50 Street, Olds, AB, T4H 1R6 Canada; tel. 1-800-661-6537 ext. 4683. Or you can find them on the Alberta Environmental Protection website at:
http://www.gov.ab.ca/env/
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California Integrated Waste Management Board
website: http://www.ciwmb.ca.gov/ Organics outlook home page:
http://www.ciwmb.ca.gov/organics/
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Washington State University/Whatcom County Extension Master Composter Home Page. The
Master Composter program is trying to increase use of composted dairy manure by local homeowners and gardeners thereby creating a market pull for more composting on farms. A Manure Compost
Marketing Guide is nearing completion. Their web site is:
http://whatcom.wsu.edu/ag/homehort/compost/compostin
g.htm
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Organic Soil Amendments and Fertilizers. 1992.
By D.E. Chaney, L.E. Drinkwater, and G.S. Pettygrove. Publ. 21505, DANR, University of California, Oakland, CA. This concise publication covers soil organic matter, evaluating organic materials, and the types of organic amendments and fertilizers. Contact DANR at (510) 642-2431 to order. Y
Organic Farming Research Foundation. Research
project reports are now available describing the results of the various funded projects. These include several reports on the use of compost tea for disease control, nitrogen management studies with compost in bell peppers, and several systems study in which compost was a fertility input. Reports are available for $2 each. Contact OFRF, P.O. Box 440, Santa Cruz, CA 95061; tel. 831-426-6606; email: [email protected]
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Compost Calendar
CERWA Summer Compost Tours (see insert).
July 16-18 – Colorado
Date TBA – Thurston Co., WA August 4 – Whatcom Co., WA August 21- Salinas Vallye, CA
October 28-29, 1999. Composting for Home and
Industry. American Society of Testing Materials
symposium, New Orleans, LA. Contact Keith Hoddinott at 410-671-5209 for more information.
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THANK YOU to Bob Rynk !!!
Bob Rynk, extension waste management specialist at the University of Idaho, has been the leader of the CERWA project for the past two years. He brought the collaborators together from the Western States to initially develop the proposal. Bob worked tirelessly to produce the first two satellite broadcasts on composting and compost use in the West. But Bob and his family have just left Idaho to relocate in the Northeast. Everyone who has worked with Bob will miss him, his wealth of knowledge about composting, and his great sense of humor. We wish him the best in his new compost connections and hope we will have a chance to continue to work with him. Thanks for all your contributions, Bob.
Comments and submissions for this
newsletter are welcome ! Contact the
Editor.
Newsletter Editor
Newsletter Editor:
David Granatstein
Washington State University Cooperative Extension / Center for Sustaining Agriculture and Natural Resources
1100 Western Ave. N. Wenatchee, WA 98801 Tel. 509-663-8181 x.222 email: [email protected]
Past issues of this newsletter can be found on the
CSANR web site at:
http://csanr.wsu.edu/compost/
Funding for this issue comes from grants from the western region USDA-SARE program.
Cooperative Extension programs and employment are available to all without discrimination.
The Compost Connection WSU TFREC
1100 N. Western Ave. Wenatchee, WA 98801