In mid-1998, the CIWMB contracted with LandLab at California State Polytechnic University, Pomona (Cal Poly) to search for any existing specifications that might have relevance to California, to evaluate those identified, and to recommend specification parameters. As part of this effort, LandLab made a survey of compost and mulch specifications being used not only within California, but in other states and countries, particularly Europe. Examples of specifications were sought from compost and mulch producers, from large-scale users such as Caltrans, from universities and private research labs, from professional user groups such as landscapers, landscape architects, and nurserymen, and from compost experts at large.
The goal of the project was to smooth the procurement process, and also to improve purchasers’ understanding of the ways that compost and mulch requirements can vary according to different end uses. Specifications can help to avoid disappointment from poor quality material, but they can also help keep costs down by avoiding purchase of material that is needlessly “overrefined” for the job at hand.
“Specifications” vs. “Standards”
The work deliberately excluded any detailed analysis of health and risk standards, because these standards have been addressed by state and federal agencies having much greater resources and expertise, especially in making long-term risk-based studies. Specifications, on the other hand, simply make reference to relevant standards developed by others, such as EPA Part 503 standards for trace contaminants, or product quality certifications from groups such as CCQC (California Compost Quality Council), OMRI (Organic Materials Review Institute), CCOF (California Certified Organic Farmers), and the U.S. Composting Council.
The specifications sought by this project at Cal Poly Pomona addressed a broad set of parameters — such as particle size, compost maturity, organic content, levels of moisture, nutrients, salt, and inert but visible contaminants. All these factors and more need to be considered individually, depending on each application, and it seemed to us unwise to subsume them under a single integrated grading scale.
A second reason not to use an A-B-C grading system is that this can imply something is wrong with “C” grade material, as if such products should be avoided if one can possibly afford something better. Yet material that falls “out of spec” for some applications is often exactly suitable for others, and should not have the stigma of being rated as second- or third-class.
What Compost Parameters Are Most Important?
While a single grade helps simplify the definition of “quality” and makes it easier to open markets to the casual buyer, one can assume that people tasked with bulk procurement can take time for a little more thought about what they’re buying. Nevertheless, simplicity is still valuable, for any first-time buyer, so we tried to pin down the minimum requirements for compost and mulch specifications. Among other tactics, we asked workshop participants to name and rank the factors they deemed most important for specifying compost characteristics.
For compost, the top-ranked seven parameters were named in the following order (most important first): Particle size; Salt concentration; Stability/Maturity; Feedstock materials; Nutrient concentrations; Visible contaminants; and Trace contaminants (at minimum, must meet EPA Part 503). The next tier of seven characteristics were then ranked: pH; C:N ratio; Moisture content; Organic matter content; Certifications; Bulk density and Other considerations.
Some workshop participants also pointed out that a few major considerations were missing from the list altogether. For example, some leading experts on disease suppression and soil ecology pointed out that one of the most useful properties of compost is that it provides a rich mix of microbes comprising several complementary functional groups (bacteria, protozoa, and so on). The presence of biological complexity is sometimes implied by the term compost “maturity,” but many feel that microbe populations in finished compost are key to delivery of its major benefits.
Gaps Between “Spec” Writing And Compost Expertise
The LandLab survey led us to contact many groups who expressed the need for specifications, and sometimes the intent to develop them, but in practice only scattered examples exist. Some of the most knowledgeable groups have focused their attention elsewhere. University-based researchers tend to focus on controlled lab experiments or field trials, to evaluate in some detail the performance aspects of compost such as growth enhancement or disease suppression for particular plant species. Yet performance criteria cannot usually be written into specifications, despite the fact that disease suppression is becoming a more widely recognized benefit of compost, and is often the primary reason for compost use, especially in agriculture.
The most complete specifications found in this project typically came from state transportation agencies, which habitually write specs for road maintenance work, using mulch and compost for roadside landscaping and erosion control. Ironically, the most widely used specifications are written by people who make no claim to be compost “experts,” although experts are generally consulted in the drafting process.
The specification formats developed in the LandLab project have much in common with various earlier examples, especially those of the U.S. Composting Council, whose work has been well funded, substantially peer-reviewed, and refined over several years of practical use. Because the Council’s Field Guide to Compost Use (1996) is relatively well known, it is useful to compare our own project with that publication.
We ended up following a similar format in the sense that our specifications: Distinguished between roughly a dozen different end uses, such as backfill mix, field nurseries, growing media, tree farming, and erosion control; Emphasized the need for simplicity and practicality, supplementing specifications with brief information on how to apply the material on site; Used caution about specifying numerical values required of a compost product, but instead required that the vendor be explicit about values to describe the material provided
In some respects, however, we departed somewhat from the Council’s Field Guide:: We combined certain categories of application where similar compost parameters were called for; We created a “generic” specification as a point of departure for defining typical parameters. Then, for any particular end use, those parameters having distinctive requirements could be highlighted. For example, growing media (or hydroseeding for erosion control) calls for small particle size, high stability (or maturity), low levels of salt, and careful screening against visible contaminants; and We treated mulch separately, creating a separate, stand-alone package of specifications and user guides.
In two workshops — one for “experts” and another for diverse user groups, the LandLab project sought to determine which parameters are most important to call out in a specification. Some of our findings:
The important parameters vary with each application. For example, salt content and maturity are critical for growing media, whereas particle size is important for top dressing. On the other hand, certifications and feedstock material descriptions have higher priority for compost use in growing of organic crops.
Professional background — or personal philosophy — makes a difference. Some experts and users, especially those coming at this business from a waste management or engineering or regulatory background, tend to focus on the physical and chemical characteristics of compost, such as particle size, trace contaminants, pH, and bulk density. In contrast, those more oriented to soil science, biology and organic growing put more emphasis on the importance of compost maturity, organic content, C:N ratio, nutrients (including trace nutrients), microbial characteristics, and feedstock disclosure.
The Feedstock Issue
Probably the most contentious issue raised in the project was whether a specification should insist on disclosure of feedstock, especially in the case of biosolids ingredients. Most people in the work- shops agreed that disclosure is important simply because this at least informs the user about what kinds of monitoring, laboratory testing and other cautions may be appropriate. In addition, anyone purchasing bulk materials should be able to respond fully and openly to any questions raised in connection with their use.
Arguments against disclosure are typically based on trying to avoid the overreaction among some people against use of biosolids, whether based on misperceptions of risks, or lack of understanding about the extensive risk-based analysis undertaken by the U.S. EPA, or fear-mongering by vendors who seek a marketing advantage by claiming a “sewage-free” product while touting the dangers of sludge. Farmers who themselves have no reservations about use of biosolids may avoid its use simply because the wholesalers they supply may believe that their retailers in turn may worry about their customers’ sensitivities — a matter of fearing the fears of others, several times removed.
Most workshop participants seemed to believe that feedstock disclosure is useful, and in some cases imperative. A huge job lies ahead for public education that dispels needless fears about biosolids use, while also recognizing legitimate concerns. The industry can also benefit from finding ways to avoid negative marketing that promotes fears and distorts risk perceptions. Meanwhile, however, there seems to be a strong majority in favor of feedstock disclosure, because issues are rarely resolved by keeping them out of public view.
Marketing Lessons From Commercial Fertilizer Vendors
One of the biggest lessons from the LandLab project at Cal Poly Pomona comes from the growing use of compost in agriculture, which may point the way for bulk procurement in urban areas. As mentioned earlier, one of the biggest selling points for farmers is the potential of compost to reduce plant disease. Yet this benefit cannot be written into a performance specification, and the evidence for it, though compelling, is largely anecdotal, outside of laboratory experiments that have focused on a small subset of plants and pathogens. No matter what is written into a specification, then, word of mouth understandings and vendor credibility and reputation may always be of equal or greater importance in developing bulk markets for organic recycled materials in urban areas as well.
A second lesson from agriculture is the importance of vendor services beyond delivery of the goods. One reason farmers have sometimes been reluctant to make the switch is the long-standing relationship they have developed with vendors, the reliable consistency of the product, very rapid turnaround time for delivery, and related services such as vendor-managed arrangements for spreading of material on site, soil testing, and providing of trouble shooting advice.
In contrast, a farmer often doesn’t know even what to ask for when ordering compost. Specifications are designed to fill that gap, of course, and to make the whole process easier. But specs are only the first step — only part of a larger framework of customer-oriented professional services that make up a long-term marketing relationship. Specifications themselves may need to address more than the characteristics of the material, to include the kind of service support now provided by many commercial fertilizer suppliers.
To a certain extent, this is already beginning to happen. Some bulk suppliers of compost to farmers stress rapid delivery, arrange with third parties for field application, and provide custom blends of compost with other amendments such as supplemental nutrients and chemicals for pH adjustment.
Technical assistance may be another key element of a delivery contract, if only in the form of useful contacts with extension agents, knowledgeable experts, soil microbiology labs, and access to training or informational materials, to build up the client’s understanding of compost characteristics and performance, and reinforce long range confidence in its use.
For development of urban bulk markets for compost, then, vendors may have to do more than develop a superior product and wait for buyers to beat a path to their door. The real challenge may lie in becoming a full-service contractor, based on a concerted effort to see the opportunities and obstacles to compost use through the eyes of each customer. A tall order, but after all, what else does “marketing” really mean?