Nearing the close of its second year, this program is well on its way to meeting these challenges with 40 percent of the available organics now composted. Feedstocks of manure, grass clippings, wood materials and yard trimmings are all generated in the Presidio. The eventual goal of composting 100 percent of the organic residuals will save the Presidio Trust over $100,000 annually.
Reaching economic sustainability is only one of our concerns; producing a quality product is essential. Aside from continuous monitoring, we are researching applications for the compost since the Presidio contains a golf course, habitat restoration sites, historical landscapes, and historic plantation forests. Other research is studying the effects of compost tea for golf course greens, growing native plants in compost at the nursery, monitoring effects of compost on transplant survival, and composting invasive weeds.
Launching The Program
In the first stage of development, the focus was on the nuts and bolts of composting: learning the feedstocks and feasibility of establishing a large-scale composting program in the Presidio. Small hand built piles were used as tests to evaluate proper recipe development, composting techniques, labor issues, and compost distribution. During this stage, we were able to develop a system for using the compost in the park. Building a base of compost users in turn enabled us to determine product demand for the compost and plan for the future.
Park partners such as AmeriCorps, National Park Service, Golden Gate National Parks Association (GGNPA), San Francisco and Marin Conservation Corps, Friends of the Urban Forest, and the Biodynamic Farming and Gardening Association became involved in various aspects of the program. By partnering with the National Park Service staff, our site became a destination for park volunteers. They helped us make compost piles, restore old equipment, turn piles, and distribute compost. Organizations like the Biodynamic Association and the GGNPA helped us promote the idea of using compost in the park.
Higher Output With Little Cost
The stage was set for the second phase of the project, moving into higher output without compromising quality or investing too much capital. We moved from hand built piles to use of a front-end loader. Our production of compost increased from 100 cubic yards (cy) annually to 2,000 cy, using the recipes we had developed to maintain the same quality. With the increased production, we began to distribute compost to our identified users. These include the Presidio Golf Course (managed by Arnold Palmer) for turf topdressing, native plant outplanting amendment, nursery potting medium and compost tea production.
We acquired two important pieces of equipment with minimal capital investment. One is an old mid-sized grinder; with some elbow grease and new parts, we got it up and running. Eventually we will grow beyond this equipment, but the investment of $50 was certainly money well spent. The second piece of equipment is being built by a team of Presidio Trust employees, a trommel screen out of salvaged materials from the park. Not only will this save us more money, but it also is a great project for fellow employees to see recycling at work. Reconditioning both pieces of equipment saved us over $60,000.
We are scheduled to transition into the third phase of this program in the fall of 2001, which will further increase production. Our goal is to compost all of the green debris the Presidio is generating. Larger equipment will be needed for this transition; however, with the savings from the previous phases, funding will be easier to justify. It is expected that annual production will increase from 2,000 cy to 5,500 cy.
Improving Survival Rate Of Transplants
Over the last two years, we have conducted numerous studies and pilot projects with the compost we produce. One such study is the use of compost to establish transplanted native plants.
San Francisco’s native ecosystem is a complex sand dune community, but only remnants survive. Part of the mission of the Presidio is to secure those populations and expand them. One of the obstacles is getting the transplanted native plants to survive once they are planted in the field. They seem to have a hard time transitioning from the nurturing environment of the nursery to the “wild.” Compost can help buffer the shock of this transition by acting as a natural fertilizer and microorganism inoculum to the transplants, and aiding water retention in these sand-dominated soils. There are several studies underway to look at the effects of compost on the survival of these plants. One study is looking at the survival of oaks with and without compost. Another study has been tracking various native plants at two restoration sites. We expect results from these studies in the early months of 2001.
Compost was also used as a planting medium for 5,000 native plants this year, about ten percent of the annual production of the Native Plant Nursery. Overall, most plants performed as well and some better than the potting mix with synthetic fertilizer. The nursery managers are excited about the prospects of using a sustainable alternative to their potting mix. Also, we believe that the compost may be capturing the native microorganisms in the Presidio and thus benefiting the native plants, something that would not be found in the potting soil.
Compost Tea On The Golf Course
The Presidio Golf Course is striving to alter its turf management practices from conventional to sustainable. We are implementing a study to monitor the effects of compost tea on the turf. Our objective is to increase humic acids in the soils and to deliver millions of beneficial microorganisms to the turf. If the tea is successful, the golf course will be able to drastically reduce the amount of fertilizers and pesticides used. In areas where compost can not be applied or tilled into the soil, the tea allows delivery of many compost benefits. Future projects will include using the tea to help depleted soils in our plantation forests, disease suppression in the Native Plant Nursery, and to help recondition soils in restoration sites.
In many respects, the educational component of the program is the most vital for its success. We are creating a community that understands the value of large-scale composting. It is our opportunity to share with children and adults the values that come with being conscious of our waste stream. Because we are a program in a national park, we have a responsibility not only to ensure we are making an excellent product, but that we can share the knowledge of such an adventure.
We have written articles about the program and given presentations to share some of the findings from our studies. It has also been important to share the implications of large-scale composting in a national park. A program such as this can illustrate what preserving our national parks may look like in the next millennium, that we must not only protect our resources, but also restore resources like our soils.
Every week school children from around the Bay Area participate in sifting, turning, and making compost piles through a program organized by the National Park Service and the GGNPA called “Here’s the Dirt.” Students come out for the day to participate in many of the daily chores around the nursery. It is an excellent way for teachers to extend their science lessons and for the children to see how composting their food scraps can be involved in a larger issue.
Future Changes At Yosemite And Yellowstone
Around the nation, many other parks are starting to look at their residuals issues and turning towards composting as a viable solution. Every park has its own problems to consider, limited space, limited funds, and even bears. Large parks like Yosemite and Yellowstone are considering large-scale programs that will fit their needs and those of the outlying communities. Smaller parks like Lake Roosevelt and Ft. Vancouver are experimenting with small compost bins to recycle their yard trimmings. As the program grows in the Presidio, we hope to have visitors from all over the park system come and witness how the residuals that a park generates can be considered a valuable resource.