Participatory Soil Health Evaluations in the San Luis Valley Background In Colorado’s high-elevation, cold and extremely arid San Luis Valley, irrigated crop production involves mainly potatoes, spring-seeded small grains, and forage. The situation includes declining groundwater availability, increasingly variable weather, and a generally high cost of maintaining productive soils. A devoted group of San Luis Valley farmers, crop advisers, soil scientists, and Natural Resource Conservation Service (NRCS) staff meet on a near-monthly basis, and have since 2010, to discuss soil health principles and locally adaptable practices. Agriculturalists’ interest in soil health remains strong, however severe drought, and prolonged overdraft of groundwater has growers questioning the economics of expending scarce water and growing-season time for cover crop use. Local groundwater management authorities presently offer cost-share incentives for farmers to fallow their fields for twelve consecutive months so groundwater pumping may be curtailed. Such policies challenge the farmer intent on increasing biological diversity and maintaining a living root in the soil for longer. The immediate cash offer to fallow a field for the year is being balanced with the largely felt, but not farmer-quantified, economic impact of implementing soil health principles into the farming system. An especially difficult choice in present times of low commodity prices. Soil amendment with locally available compost (which was actively turned and bacterial dominated) used to be cost-shared through EQIP in this valley as a soil health practice, but the EQIP cost share was discontinued. Over multiple years, many farmers weren’t seeing consistent effects, even from heavy, expensive application rates. To date the only commercially-available compost in the region continues to be an actively aerated, highly bacterial compost product. Cover cropping, even with EQIP cost share on seed, has had limited adoption here (and in tilled systems in southwestern USA) due to perceived minor benefits towards soil health relative to cost, including the cost of pumping water from an overdrafted aquifer. So what’s missing? What is limiting the effects of cover cropping and compost amendments? What is missing in our systems to achieve soil health, water use efficiency, and lowered costs of production? How might we work together to creatively fill these gaps? In 2004 Colorado passed a law mandating the recovery of the aquifer under the valley. Water use efficiency, with 6-7 inch average rainfall, is a critical challenge. What drives both crop productivity and soil health is the flow of sunlight energy. Photosynthesis produces carbohydrates, which feed soil biology, which in turn influences crop productivity, water retention and water use efficiency, and nutrient use efficiency—all of which are significant challenges in the San Luis Valley and in much of the arid western U.S. Fungi and bacteria are the base of the soil food-web, responsible for the majority of the decomposition of soil organic matter. They are key regulators of the enormous flow of sunlight energy through the soil system. Here’s a more technical explanation: The fungal/bacterial ratio in the soil microbiome influences what happens to plant photosynthates: whether they are partitioned into secondary-assimilated biomass or lost from the soil through respiration (Six et al. 2006). Higher fungal/bacterial ratios are associated with a higher quality and quantity of soil organic matter (Six et al., 2006), and also associated with observed variances in soil carbon use efficiencies (CUE). CUE is defined as the proportion of photosynthate C acquired from the environment that is used for growth (Bradford & Crowther, 2013) or the conversion of plant-produced carbohydrates into microbial products (Sensabaugh, 2013). Values for CUE range between 0.10 to 0.80, with high CUE promoting greater amounts of secondary-C assimilation and higher levels of C stabilization in soils, while lower CUE indicates higher respiration of uptake C to CO2 and reduced levels of C stabilized in soils (Keiblinger et al., 2010). The magnitude of the differences between these low and high estimates of CUE have been observed to be a function of soil fertility, ecological factors, and microbial community composition, with higher-fertility soils and fungal-dominant microbial communities demonstrating higher CUE (Keiblinger et al, 2010, Comis, 2002, Sollins et al., 2009, Manzoni et al., 2013, Six et al., 2006). Dr. David Johnson, a researcher at New Mexico State, has developed a static pile compost process (where the compost is not turned), resulting in fungal-dominated compost for use in low amounts per acre as an inoculant, increasing the fungal/bacterial ratio in soil. His research has observed the potential to improve: plant productivity (5 times increase in net primary productivity and a doubling of commodity crop production) soil health (improved soil nutrient availability, increased crop water use efficiency, and soil carbon use efficiencies) and a farmer’s bottom line (higher yields while using fewer nutrient and herbicide/pesticide inputs), when we focus our efforts on restoring the biological barter that can exist between a plant and its soil microbiome In greenhouse and field trials in southern New Mexico, Johnson has recorded significantly higher productivity, water use efficiency, and nutrient use efficiency with these practices. But there has been limited deployment, particularly at field scale. In January 2018 the Mosca-Hooper Conservation District hosted David Johnson’s presentations on the static-pile, fungal-dominated compost process, the importance of the soil fungal/bacterial ratio, the synergy with cover cropping, and the excellent results from trials. There was strong interest by farmers. Already in 2018, eighteen farmers have agreed to cooperate with the Mosca-Hooper Conservation District in making static pile compost, which takes a year to produce high-fungal compost suitable for low-rate (400 lbs./acre) inoculation applications to fields. These farmers also want to combine the compost inoculation with cover cropping and gauge the effects of this combination. This is a co-creation or “chicken-plus-egg” strategy: Cover crops can supply energy flow into the soil microbial community between primary cash crops, but if this community remains highly bacterial, this energy is quickly lost. Higher fungal/bacterial ratios can slow the release of this energy and carbon, promoting crop productivity, water use efficiency, nutrient use efficiency, resilience to pests and diseases, and overall soil health. Needs for innovation. There is a general lack of farmer training to do repeatable soil health assessments on their own fields, and to record these metrics in a way that is meaningful and accessible for future reference or repeated assessments, or with the option of sharing. Regionally adapted soil health metrics have been developed but are not widely utilized. The absence of simple data management is a major impediment for farmer decision-making regarding crop, range, and conservation planning. There is also limited communication between farmers regarding benefits (or downfalls) of soil health monitoring, and its connection to productivity, cost of production, or soil function. Most data and research results remain hidden from most people, from farmers, extension agents, from most stakeholders in natural resource issues. This is both a technical problem of access and research-centric data schemas, and a human problem of access, context, participation, and interpretation. Objectives Improve productivity, water use efficiency, and lower the cost of maintaining soil fertility in irrigated cropland and forage production Build capacity among farmers and stakeholders to make soil health evaluations, learn, innovate, adapt, and spread soil health innovations Innovative approaches: • High-fungal compost application with cover cropping • Open-source, flexible, citizen-usable data platforms that support research data collection as well as participatory soil health evaluations, and that support: • A shared, collaborative, respectful, site-specific, evidence-based intelligence on soil health and function that promotes and spreads integrated, adaptive soil health management systems NRCS Conservation Practice Standards into which our project metrics and outcomes could be integrated include: 138. Conservation Plan Supporting Organic Transition: based on identification of increased nutrient use efficiencies utilizing organic-qualifiable fungal-rich compost into crop and soil management plan, soil biological and physical testing to inform whether indications of system functionality are abundant, identification of most useful soil testing suite for local conditions to answer questions of system functionality and potential for efficiency and productivity 317. Composting Facility: adaptation of facility and processes design to deliver economical and high-quality finished material Conservation Cover: based on changes in soil physical properties including aggregate stability and bulk density relative to local soil & environmental conditions, integration of soil fungal/bacterial ratio, duration of living root & green cover, and percent total cover as planning considerations Conservation Crop Rotation: based on duration of green cover & living root, soil aggregate formation dynamics, water use efficiency, and likelihood of cover persisting relative to crop rotation sequence 340. Cover Crop: based on water use efficiency, duration of green cover & living root, microbial dynamics of highest and lowest producing systems involving cover crops, nutrient use efficiency findings 345. Residue and Tillage Management, Reduced Till: adaptation of practice based on whether timing, intensity, and frequency of tillage relative to fungal-rich compost-treated cover crop growth impacts soil health metrics, system water use efficiency, and ground cover 449. Irrigation Water Management: based on changes in cropping system’s water use efficiency, soil bulk density and infiltration rates in response to incorporation of fungal-rich compost paired with cover crops 512. Forage and Biomass Planting: based on findings from project fields where crops were paired with fungal-rich compost and utilized for forage and/or grazing, relative to their capacity to cycle energy, increase carbon use efficiency, and improve water use efficiency 590. Nutrient Management Plan: based on findings of increased nutrient use efficiency from particular cropping systems, soil testing methods including fungal/bacterial ratio, low-cost microbial testing through biomarker determination to anticipate soil’s nutrient release capacity (metatranscriptome and rRNA 16S/18S to determine low-cost test for specific biomarkers) 595. Integrated Pest Management: integrating cover crop species & cultivar specific logic relative to microbial associations they foster, to induce suppression of soilborne pathogens or increased prevalence of symbiotic/predatory microbial functional groups in soil, for tailoring pest management plans to manage soil microbiome of field towards more effective pest control, utilization of metatranscriptome and rRNA 16S/18S to inform potential impact of crop selection and management practices on pest management 610. Salinity and Sodic Soil Management: based on observations of salt-affected soils in response to fungal-rich compost addition to cover crop, soil chemical, physical and microbial properties relative to crop productivity and water & nutrient use efficiency to inform practice standards Methods Both the objectives and methods of this project involve creative combinations. The Mosca-Hooper Conservation District seeks to leverage static-pile high-fungal compost inoculation, plus the demonstrated interest and commitment of 18 San Luis Valley farmers, with: cover cropping to provide food for helping to improve the population, structure and biological functionality of the soil microbial community lab analyses and research to convey changes in soil biological, physical, and chemical properties before and after the compost inoculation and cover cropping (both quantitative and qualitative) over a three year trial period. flexible, open-source data systems that help record and interpret the lab analyses and research, incorporate relevant existing data, and that also support and record: repeatable, georeferenced, and participatory soil health evaluations such as infiltration, visual soil assessments, water use efficiency, and economics of production practices Our method is not a linear path from a practice to a result, but an exploration of relationships: between soil biology, energy flow, economics of production, and our capacity to learn, share, and adapt, using the following methods and tools: Fungal-dominant compost. Making enough static-pile compost for inoculation of 500 or so acres is already committed, and will be done with advice from David Johnson, as well as quality assurance and control through periodic lab testing. The Mosca-Hooper Conservation District will also purchase a compost extractor. Some of the benefits of high-fungal compost can be achieved with compost extract (Welke 2005) which consists of exudates and enzymes but not high populations of living organisms. The compost extractor will make it possible to broaden participation in this experiment, including smaller-scale producers and those who do not participate in government grant projects, but who could contribute data and learning. Cover cropping between cash crops. Most of the 18 cooperator farms have committed 60 acres to the experiment which they will plant with multispecies cover crops. On half the acreage (30 in most cases), high-fungal compost inocula will be applied. Data platforms. Soil Carbon Coalition will set up a web server for the project, with flexible data frameworks consisting of atlasbiowork.com, an open-source, offline-capable web app, plus FarmOS, an open-source farm and ranch management tracking system with maps and plugins for sensor feeds. This will be a data portal for the project, and will accommodate data mapping for the San Luis Valley, with easy extension to the five conservation districts in Colorado that form the Rio Grande Watershed Association of Conservation Districts (upper Rio Grande watershed). These open-source, interoperable data platforms will enable cooperators and partners to track project activities, measurements, and observations across time as well as georeferenced to points or polygons. We will tread gingerly around data privacy. Both platforms are highly adaptable, with new data forms added easily, and with built-in portability of data to other websites or data systems. Atlasbiowork is also an offline-capable data-entry platform adapted to infiltration timings, site photos, and comparing repeated observations at the same site on layered maps. Normalized difference vegetation index (NDVI) maps of the valley will be generated from Landsat 8 and Sentinel data and can be displayed as length of green season (energy flow) for each year. Some relevant nematode data, chemical soil analyses, and groundwater information will also be collected from available and willing sources, and made available as map layers to give broader context for the project. Complicated multicolored maps, geographic information systems, or any kind of data or information are not a guarantee of learning. We need to continually adapt data presentation and interpretation to human contexts. The emphasis with these data systems is on usability and ease of interpretation rather than highly complex, rigid, or jargon-rich data structures that repel participation and make it difficult to put data in context. Web and digital technology changes rapidly. With open-source systems we can ensure data portability (such as JSON export via an API), so that we are not embalming project data into potentially obsolete proprietary formats. Data collection will include the recording of the field segments as polygons, and the establishment of two sampling sites on each cover cropped field, one with compost treatment, one without, but on the same soil type for comparison. These sampling sites will be located with GPS coordinates, plus tape measure and repeatable lines of sight. Soil Health Services will take a variety of samples at each site at baseline (before compost application), recorded as to time and location, and repeated at a 3-year interval. Soil analyses will include: Cornell soil health test Haney test Carbon-nitrogen analysis on 3 depth increments Bulk density on same 3 depth increments 16S/18S rRNA sequencing (Dan Manter, ARS Fort Collins) This data collection will be repeated at the 3-year interval from the same sites. In addition to the above analyses, David Johnson will also sample for a metatranscriptome analysis, with samples stabilized and stored under refrigeration for the duration of the project. After the 3-year resampling, he will have a subset of the metatranscriptome samples analyzed from best and worst performing fields. The focus of this research is to examine the influence of a beneficial soil microbial community inocula produced in a Johnson-Su bioreactor for improving plant productivity, soil health, soil fertility, and the soil microbiome changes that facilitate these soil attributes. Participatory soil health evaluations. Throughout the project, cooperators and partners including Soil Health Services, Soil Carbon Coalition, Rio Grande Watershed Conservation and Education Initiative, David Johnson, and Dan Manter will engage with cooperators and periodically with stakeholders and high school students to do participatory soil health evaluations in the field, sometimes at the previously established sampling sites. These will include recorded observations as well as discussion of management and soil health principles and practice. Observations may include water infiltration, visual soil assessments including slake tests and aggregate stability, penetrometer resistance, biomass estimates, brix, observations related to the soil health principles of minimal disturbance, living roots, cover, and diversity, and calculations of biomass grown (estimated) or harvested (recorded by cooperator) per inch of water applied. These observations can be entered as part of the project’s data record, and retrieved and summarized by time or location. Interpretation and framing. As the logic model (see below) suggests, the integration of the various project strands requires a twist. The project will have an annual meeting to set the stage for all participants and stakeholders to help design the project, learn, and mentor others. Because we are incorporating open data systems, and because many observations as well as the diffusion of innovation will be participatory, it is critical that these meetings are facilitated in a manner that goes beyond information sharing, and builds skills in listening, sharing power, and building trust. Four annual meetings of participants and stakeholders will be held (October 2018, October 2019, October 2020, and September 2021). The first will be focused on building participation and trust, and understanding project elements, and subsequent meetings will build on this foundation, as well as enlarging the context and stakeholders. Jeff Goebel will facilitate the first project meeting, which will also be a training for project partners. Jeff will demonstrate how to create an environment for shared learning, participation, and trust based on behavior, with a participatory approach that engages everyone, respectfully, as a whole person. This approach takes more time than an information dump or powerpoint presentation, but it has proven to be highly successful in building trust and respect among participants, and guaranteeing that they have access to their own knowledge and intelligence, as well as that of others, to address the issues and objectives of the project. These methods will also be part of the field visits for participatory soil health evaluations. They help ensure that learning takes place, and some of it can be recorded, along with data and observations, as a project activity record. Data platforms and data collection will be explicitly targeted toward measuring progress toward the project’s objectives: improving productivity and water use efficiency of irrigated cropland and forage production, and building capacity among farmers and stakeholders to learn, innovate, adapt, and spread soil health innovations. Geographic location and size Our project involves several counties in Colorado’s San Luis Valley, on irrigated crop and forage land. Eighteen farmer-cooperators have committed 992 irrigated acres in 18 fields to be cover cropped for the project, and to apply the fungal-rich static-pile compost inocula on half of each field. Farms participating in this project are commercial-scale family farm operations including conventional and certified organic, center pivot irrigated, with rotations counted here by the number of summers that would pass before the same crop is planted again, consisting of: green manure cover crop-potato-barley (3 year), green manure cover crop-potato (2 year), potato-winter triticale cover - spring wheat (2 year), potato-legume/cereal hay (2 year), potato-cereal rye spring grazed-multispecies cover winter grazed-green manure summer (3 year), perennial grass & legume hay/pasture, alfalfa-legume/cereal hay (6 year). EQIP-eligible producer participation 18 EQIP-eligible farmer-cooperators have agreed to: contribute to the static pile compost process to use a cover crop -- extending to green manured, grazed, season-bridging cover crops through winters between summer cropping cycles, long-term multispecies grass/legume pastures, and fields in rotation between perennial and annual hay crops. apply the high-fungal compost inocula to a portion of their cover crop acreage cooperate with the project’s data collection, including the participatory soil health evaluations (In addition we have interest from some non-EQIP eligible producers who can partake of this process and contribute some data and potential for learning.) Action plan and timeline Eighteen San Luis Valley farmers have organized to undertake the assembly of static compost piles to produce high-fungal compost for inoculation of portions of fields that will also be cover cropped. These compost piles take at least a year, and will be in process during summer, fall, and winter of 2018-19. Abbreviations: MHCD: Mosca-Hooper Conservation District, PO: Patrick O’Neill, Soil Health Services SCC: Soil Carbon Coalition (Peter Donovan, Didi Pershouse) RGWCEI: Rio Grande Watershed Conservation & Education Initiative (Bethany Howell) What Who’s responsible, participants When Data and reporting systems installed, begin acquiring and mapping length of green seasons from NDVI and other available and relevant data SCC October 2018 First project meeting: setting the stage for active participation by cooperators and partners in soil health evaluations. What are the most important questions, what do people want to learn? Here are the soil health principles, where do they fit on my farm? Design and commitment toward a participatory inquiry. MHCD, Soil Health Services, Jeff Goebel, SCC, David Johnson, Dan Manter October 2018 First trainings with data systems SCC Oct-Nov 2018 36 sampling locations established with farmer-cooperators, with beginning of participatory evaluations. Baseline soil samples taken for chemical, physical, and biological analysis. PO, some help from SCC Oct 2018 Compost piles monitored and tested for quality: 3 soil foodweb analyses per occasion (9 samples) PO Oct 2018, Jan 2019, Apr 2019 Participatory soil assessments continue with students, cooperators, project partners PO, SCC, RGWCEI In fields October 2018 and ongoing, fall preferred Compost application beginning spring 2019 and continuing right after potato harvest cooperators May-Oct 2019 Cover crops planted cooperators after compost applied Compost extractor purchase and setup MHCD Spring 2019 2nd project meeting MHCD, Jeff Goebel Oct 2019 Outreach. Quarterly watershed meetings, state assoc meetings, SWCS annual, cooperators and stakeholders present project to other districts and groups MHCD July 2019 through spring 2021 3rd project meeting MHCD, Jeff Goebel October 2020 Resampling at 3-year interval. PO Sept 2021 Final project meeting, wrap-up, fact sheet, and web pages MHCD, Jeff Goebel September 2021 Project management Kelley Baily, Mosca-Hooper Conservation District Manager will be the project manager. Ms. Baily has extensive experience in communications, marketing and grant administration. Ms. Baily maintains an active presence on social media on behalf of the Mosca-Hooper Conservation District, assisting landowners in the region access up-to-date District news, announcements on conservation-related policy & programs. Subcontractors: Patrick O’Neill, Soil Health Services will be the primary soil sampler and project coordinator. Mr. O’Neill is a soil scientist and agronomist with experience in advising farmers and ranchers on crop production, system management for soil health development, and in developing protocols for quality control and quality assurance relative to in-field sampling and sample handling. Mr. O’Neill has assisted with coordination of the San Luis Valley Soil Health Working Group, a volunteer network of farmers, ranchers, agricultural advisers & researchers, and other agricultural stakeholders since 2010. David Johnson who developed the Johnson-Su bioreactor process will be advising on the static compost process, sampling for microbial analyses, and advising and presenting at some project meetings. Dr. Johnson has researched the influence of the population, structure and biological functionality of soil microbes using genomics, metagenomics and metatranscriptomics, over the last decade and a half, assessing the potential for regenerating soil microbiota for improving the fertility, health and productivity of soils in agroecosystems. Dan Manter, a microbial ecologist with ARS at Fort Collins who has done extensive phylogenetics work, will also participate in the sampling and analysis of microbial genetics. Jeff Goebel has over twenty years of national and international successes in consensus building, conflict resolution, and visioning for sustainable solutions. He has worked on catalyzing positive change with non-profits, government agencies, multinational corporations, and family farmers and ranchers. He has developed a highly effective program of respectful listening, visioning, and planning that attains long-range and long-lasting change through 100% consensus and “buy-in” of all parties. Soil Carbon Coalition will install data platforms, populate with NDVI maps and some legacy data, provide training on use of data platforms, and help facilitate participatory soil health evaluations. Peter Donovan has sampled soils all over North America for soil carbon change, and teaches workshops on citizen-accessible ways observing and recording repeatable observations on the carbon cycle and water cycle. He is the founder of the Soil Carbon Coalition, and has developed an open-source web app (atlasbiowork.com) to popularize flexible, participatory data entry. Didi Pershouse of the Soil Carbon Coalition has taught soil health principles to students and teachers, and has authored a popular teaching manual on soil health and watershed function that has been endorsed by the NRCS. Bethany Howell (Rio Grande Watershed Conservation and Education Initiative) has organized and facilitated many soil health and watershed workshops with students in the San Luis Valley, in classrooms and in the field. She will help organize and facilitate some of the participatory soil health evaluations and include student groups. Deliverables/products Logs of activities, field visits, and measurements can be readily compiled or exported from the data platforms atlasbiowork.com and FarmOS as both interactive maps and tables. Portions of these platforms can also be publicly accessed through the project website. MHCD will maintain an event calendar on the project website of all events and project activities, and invite NRCS technical representatives to project annual meetings as well as any outreach presentations. MHCD will compile a report every 6 months on money spent, project progress, with a summary of activities, some photos, and data. MHCD will compile annual reports following each annual project meeting (October) that also include interviews with project participants and what we’ve learned so far. Benefits or results expected and transferability Improved soil health and stability in San Luis Valley, along with increased crop production and cropping system water use efficiency. Social and human capital: trust, shared learning, and collaboration among farmers, partners, and those who have a stake in the agricultural economy of the San Luis Valley. Flexible and adaptable open-source data mapping platforms, for continued learning and incorporating data into decisions. Maps are a key to understanding data. Coordination of data relevant to soil health, biological energy flow, and watershed function on a layered, citizen-usable map of the San Luis Valley. We can map function, not just the parts or the problems, and in so doing, build management capacity, learning through participation, and a shared intelligence that will help the Mosca-Hooper Conservation District and its stakeholders to evaluate its impact and activities. This data will have a high degree of portability and computability. Transparent and replicable model. It’s possible to do this elsewhere, and extend some of the same benefits, at low cost. Because this project will use open and open-source data systems, the design, implementation, and results of the project will have an unusually high degree of transparency, including easy visual recognition from map layers. MHCD board members and volunteer cooperators, plus partners when available, will present the results of the project along with the contributing strands and people-centered design. MHCD and partners have access to many networks for outreach: conservation district associations, quarterly watershed meetings, the Soil Health Champions network, and Colorado State University. Lasting impact: increased capacity in the San Luis Valley for integrated, adaptive management based on shared evidence, with increasing soil health, lowered cost of production, and increased water use efficiency. Evaluation As noted, the data systems and data collection are specifically targeted toward measuring progress toward the project’s objectives: productivity, water use efficiency, lower the cost of maintaining soil fertility in irrigated cropland and forage production, and build capacity among farmers and stakeholders to make soil health evaluations, learn, innovate, adapt, and spread soil health innovations. Evaluation and feedback are not a programmatic add-on, but an inherent part of the design. The project data platforms (atlasbiowork.com, FarmOS) will be a citizen-usable portal to much of the project’s data, most of which can be displayed as maps or tables. Advanced-level data analysis will be available (via a Jupyter notebook interface), somewhat dependent on the data permissions we agree on during the project. The data will be highly computable (even if all of it is not exactly geolocated for privacy reasons) around a variety of purposes. We will train all participants and partners in use of the portal, so that any participant has some ability to evaluate the project in relation to its objectives, and to evaluate the performance of their field or farm. Each annual meeting ends with a round of evaluation: what did you learn that will help you be successful, and how do you feel about it? The project team will record some of this, not necessarily with attribution. References Bradford, M.A., Crowther, T.W, 2013. Carbon use efficiency and storage in terrestrial ecosystems. New Phytol. 199(1), 7-9. Chadwick, Bob. Finding New Ground (2013). This book, by a former US Forest Service Forest Supervisor, is a detailed and sensitive guide for facilitators, for creating and maintaining an environment “where people purposefully learn from each other, even from those with opposing views, and build a more comprehensive view from their interlocking realities, where this knowledge is applied to create not just ‘common ground’ but ‘new ground,’ where all can agree that their interests are taken care of and they behave the agreement, actually making it happen.” Chadwick was highly successful in helping people address natural resource conflicts and finding new ground throughout the West and Midwest during the 1990s and 2000s. Comis, D., 2002. Glomalin: Hiding Place for a Third of the World’s Stored Soil Carbon. Agric. Res. http://agresearchmag.ars.usda.gov/AR/archive/2002/Sep/soil0902.pdf Johnson, David. Best management practices for Johnson-Su compost bioreactors. http://case.nmsu.edu/case/pasodelnorteagriculturalworkshops/documents/J… nson-Su_Bioreactor_BMP.pdf Keiblinger, K.M., Hall, E.K., Wanek, W., Szukics, U., Hammerle, I., et al., 2010. The effect of resource quantity and resource stoichiometry on microbial carbon-use-efficiency. FEMS Microbiol. Ecol. 73, 430–440. Manzoni, S., Taylor, P., Richter, A., Porporato, A., Agren, G.I., 2013. Environmental and stoichiometric controls on microbial carbon-use efficiency in soils. New Phytol. 196, 79–91. Sensabaugh, R.L., Manzoni, S., Morhead, D.L., Richter, A., 2013. Carbon use efficiency of microbial communities: stoichiometry, methodology and modelling. Ecol. Let. doi: 10:1111/ele.12113. Six, J., Frey, S.D., Thiet, R.K., Batten, K.M., 2006. Bacterial and Fungal Contributions to Carbon Sequestration in Agroecosystems. Soil Sci. Soc. Am. J. 70:555–569 (2006): 70(2), 555-569. Sollins, P., Kramer, M.G., Swanston, C., Lajtha, K., Filley, T., Aufdenkampe, A.K., Wagai, R., Bowden, R.D., et al. 2009. Sequential density fractionation across soils of contrasting mineralogy: evidence for both microbial and mineral controlled soil organic matter stabilization. Biogeochemistry 96, 209-231. Van der Ploeg, Jan Douwe, Piet Verschuren, Fran Verhoeven, and Jose Pepels. Dealing with novelties: A grassland experiment reconsidered. Journal of Environmental Policy & Planning Vol. 8, No. 3, September 2006, 199–218. DOI: 10.1080=15239080600915568 Welke, Sylvia E. (2005) The Effect of Compost Extract on the Yield of Strawberries and the Severity of Botrytis cinerea. Journal of Sustainable Agriculture 25:1, 57-68. doi.org/10.1300/J064v25n01_06
