Companion to: Deep Research Brief: Eco Farming Materials, Inputs, and Equipment. Use the master brief's evidence-confidence scale, product data schema, and research standards (defined in Part 00: Framework, Scales, and Data Schemas).

Research window: 2019 baseline through September 2026, with older long-term trials and foundational studies included where they remain the best evidence. Record the exact access date for every source.

1. How to research this part

  • Treat every named product, company, study, date, and rule in this brief as a lead to verify, not as a fact. This brief was drafted without live research.
  • Seed lists are starting points, not limits. Expand each list through distributor catalogs, material review listings, and extension publications.
  • Targets for this part:
    • At least 150 input product records (Part 00, schema 4.1), covering every category in Sections 3–11 with at least 10 records per major category.
    • At least 60 study records, including at least 15 meta-analyses or long-term trials.
    • At least 40 company records.
    • At least 20 regulation records (fertilizer labeling, biostimulants, contaminants, organic input rules).
    • At least 15 contamination or enforcement event records.
  • Discovery methods:
    • Search the OMRI Products List, WSDA Organic Input Material list, and CDFA Organic Input Materials program by category (verify current search interfaces).
    • Review catalogs of major organic farm suppliers (for example, Peaceful Valley Farm Supply, Johnny's Selected Seeds, Fedco Seeds/Organic Growers Supply, Arbico Organics, Territorial Seed, Seven Springs Farm, Hummert, and in the UK and EU, suppliers such as Fertile Fibre, Agralan, and Organic Growers Alliance member suppliers — verify).
    • Search Google Scholar, Web of Science, and CAB Abstracts for meta-analyses by input type.
    • Review extension series from Cornell, UC Davis/UC ANR, Washington State University, Oregon State, Penn State, University of Vermont, University of Minnesota, NC State, and eOrganic.
    • Review SARE project reports (projects.sare.org) for farmer trials.
    • Review trade bodies: Biological Products Industry Alliance (BPIA), The Fertilizer Institute, US Composting Council, International Biochar Initiative, US Biochar Initiative, European Biostimulants Industry Council (EBIC), European Biochar Industry Consortium (EBI).
    • Check state department of agriculture fertilizer program enforcement reports (for example, California, Oregon, Washington, Texas, Florida).
  • Separate claimed from measured. Record the label guaranteed analysis and the manufacturer's benefit claims in claimed fields; record independent lab analysis and trial results in measured fields.
  • For every input, distinguish four outcome types: (1) soil-test change, (2) yield or quality effect, (3) economic return, and (4) environmental outcome (carbon, runoff, emissions).

2. Framing questions

  • Which inputs supply nutrients directly, which change soil conditions (pH, structure, water holding), and which claim to change biology or plant physiology?
  • What is the realistic nutrient release timing of each organic fertilizer under cool vs. warm soils?
  • When is an input substitution (swapping synthetic N for feather meal) economically and ecologically sensible, and when does the system need redesign (legume cover crops, integrated livestock)?
  • Where does the evidence show consistent benefit, where is it mixed, and where is it absent?
  • What contaminants (heavy metals, PFAS, persistent herbicides, pathogens, plastics, pharmaceuticals) come with each input?

3. Compost and vermicompost

3.1 Research topics

  • Production methods: windrow, aerated static pile (ASP), covered ASP (for example, GORE cover systems — verify), in-vessel, Johnson-Su bioreactor, Berkeley rapid method, and cold/passive composting.
  • Feedstocks and carbon-to-nitrogen ratios; municipal green waste vs. manure-based vs. food waste composts.
  • Quality standards: US Composting Council Seal of Testing Assurance (STA) program and Test Methods for the Examination of Composting and Compost (TMECC); UK PAS 100; EU Fertilising Products Regulation component material category CMC 3 (compost); Canadian CCME compost guidelines (verify).
  • Maturity and stability tests: Solvita CO2 and ammonia tests, C:N ratio, germination/phytotoxicity tests.
  • Pathogen reduction: NOP compost requirements (temperature 131–170°F for 3 days in-vessel/ASP, or 15 days with 5 turnings in windrows — verify exact text at 7 CFR 205.203(c)); FSMA Produce Safety Rule treatment standards.
  • Application rates for vegetables, orchards, and field crops; phosphorus buildup risk from repeated high compost rates.
  • Vermicompost production (flow-through bins, windrows), worm species (Eisenia fetida), and evidence for plant growth effects.
  • Johnson-Su compost and "fungal-dominant compost" claims (grade carefully; research by David Johnson at New Mexico State University — verify publications and critiques).

3.2 Seed list (verify)

  • Compost producers and brands: Cedar Grove (Washington), Recology (California), Black Gold/Sun Gro, Coast of Maine, Vermont Compost Company, Malibu Compost (biodynamic claims), Purple Cow Organics, Living Earth (Texas), Dirt Hugger, Earth Care Farm (Rhode Island).
  • Worm castings: Wiggle Worm, TerraVesco, Worm Power (New York; verify status), Unco Industries.
  • UK/EU: Melcourt, Bord na Móna (peat-free transitions), Veolia compost products, Renewi.
  • Equipment makers are covered in Parts 04–05; here, focus on the material.

3.3 Evidence leads

  • Rodale Institute Farming Systems Trial compost and manure systems (verify latest 40-year report).
  • Meta-analyses on compost and soil organic carbon and crop yields (search "compost application meta-analysis soil organic carbon yield").
  • UC Davis Russell Ranch Century Experiment compost results (verify).
  • Research on compost and water holding capacity in Mediterranean climates (California Healthy Soils Program-funded demonstrations).

4. Compost teas, extracts, and liquid biological preparations

  • Distinguish aerated compost tea (ACT), non-aerated compost tea (NCT), compost extracts, and vermicompost leachate.
  • Food-safety concerns: NOP Compost Tea Task Force recommendations (2004 — verify) and certifier policies on added nutrients (molasses, kelp) and pathogen testing.
  • Claims about disease suppression and foliar microbial "coverage." Review studies by Scheuerell and Mahaffee, Oregon State, and critiques by Linda Chalker-Scott, Washington State University (verify).
  • Brewer equipment and brands: Keep It Simple (KIS) brewers, Boogie Brew, Growing Solutions (verify status).
  • "Soil Food Web" consulting approach (Elaine Ingham's Soil Food Web School) and microscopy-based soil biology assessments. Research independent evaluation and criticism, and grade claims separately from farmer satisfaction.
  • Deliverable: a table of claims vs. evidence grades for compost tea by crop and disease.

5. Animal manures and manure-based fertilizers

  • Raw, aged, and composted manure; nutrient variability by species, bedding, and storage.
  • NOP raw manure rules: incorporation 120 days before harvest for crops with soil contact, 90 days for others (verify 7 CFR 205.203(c)(1)).
  • FSMA Produce Safety Rule status for raw manure application intervals (FDA has deferred its own interval while it researches — verify current status).
  • Pelletized poultry litter products and heat-treated manure: seed brands Perdue AgriRecycle/Perdue Farms Harmony, Chickity Doo Doo, Sustane (turkey litter-based), Espoma (mixed blends), Nature Safe (Darling Ingredients), Bradfield Organics, Ferticell (Europe), Dynamic Lifter (Australia — verify).
  • Antibiotic residues and antimicrobial resistance genes in manure (grade evidence).
  • Persistent herbicide contamination (aminopyralid, clopyralid, picloram, aminocyclopyrachlor) passing through livestock fed treated hay. Include state extension alerts (for example, Washington State, Penn State, North Carolina, UK "killer compost" reports — verify) and product stewardship labels from Corteva on Milestone/GrazonNext products.
  • Neighbor sourcing checklist: questions to ask a manure or hay supplier.

6. Organic fertilizers (processed natural materials)

6.1 Materials to profile

  • Nitrogen: feather meal, blood meal, fish meal, fish emulsion, fish hydrolysate, soybean meal, alfalfa meal, cottonseed meal (and conventional cotton pesticide residue questions), hair and hoof meal, Chilean nitrate/sodium nitrate (NOP limit of 20% of crop N — verify annotation status), plant-based liquid N (for example, fermented molasses/vinasse products).
  • Phosphorus: bone meal, rock phosphate (hard and soft/colloidal), bat and seabird guano, struvite (and its organic status — verify).
  • Potassium: sulfate of potash (mined), langbeinite (Sul-Po-Mag/K-Mag), greensand, kelp meal, wood ash.
  • Micronutrients and secondary: gypsum, elemental sulfur, Epsom salt, boron sources, chelated micronutrients (check synthetic chelating agent rules).
  • Complete blends and pellets for vegetables, turf-like pasture uses, and orchards.

6.2 Seed brands and companies (verify)

  • True Organic Products (California; note the 2024–2025 California enforcement and litigation history over nitrogen sources — verify details carefully), Down to Earth (Oregon; part of Pro Tech or other ownership — verify), Espoma, Dr. Earth, Jobe's Organics, Fox Farm, Neptune's Harvest, Alaska Fish Fertilizer, Converted Organics (historical), Pacific Gro, Biolizer, Nature Safe, Suståne, Harmony, McGeary Organics, Fertrell (Pennsylvania), North Country Organics, Kreher Family Farms (5-4-3 pelletized poultry), BioFlora, Tainio Biologicals, Grow More, Italpollina/Hello Nature, Biolchim (now part of Huber — verify), Fertiberia, Ferm-O-Feed (Netherlands), Monterey Lawn and Garden, Azomite (a rock mineral product with OMRI listing — verify).
  • Liquid N makers linked to organic vegetable and berry production in California.

6.3 Fraud and enforcement leads (report carefully)

  • California Department of Food and Agriculture investigations into liquid organic fertilizers spiked with synthetic nitrogen (historical cases involving California Liquid Fertilizer / Port Organic Products in the late 2000s — verify names and outcomes).
  • Later CDFA or Oregon actions on organic input materials, and any 2023–2026 enforcement actions (verify).
  • Isotope testing (nitrogen-15) as a tool to detect synthetic N in "organic" fertilizers and crops (verify methods and labs).
  • How the Organic Input Material (OIM) registration program in California changed after fraud cases.

6.4 Research topics

  • Mineralization rates by material and soil temperature (Oregon State University "Organic Fertilizer Calculator" and associated mineralization data — verify availability).
  • Cost per kilogram or pound of actual nitrogen by material; build a price table with dates.
  • Nutrient budgets: why repeated manure/compost to meet N overloads P.
  • Supply-chain questions: imported feather meal and fishmeal sources, sustainability of guano and fish-based inputs, avian influenza impacts on poultry-derived inputs (verify any 2022–2026 supply disruptions).

7. Mineral amendments, rock dust, and enhanced rock weathering (ERW)

7.1 Conventional mineral amendments

  • Agricultural lime (calcitic vs. dolomitic), calcium carbonate equivalent and fineness ratings, pelletized lime, gypsum (mined vs. FGD gypsum and its organic status), elemental sulfur for acidification.
  • Base cation saturation ratio (BCSR, "Albrecht") approach vs. sufficiency level of available nutrients (SLAN). Summarize university critiques (for example, Kopittke and Menzies 2007 review — verify) and why many consultants still use BCSR.

7.2 Rock dust / remineralization

  • Basalt, granite, glacial rock dust, and volcanic ash products; claims of trace minerals and "remineralizing."
  • Seed products: Azomite, Rock Dust Local (Vermont — verify status), Mount St. Helens ash products, Remin (Scotland), Glensanda / "Garden Rock Dust" (UK — verify), Gaia Green Glacial Rock Dust (Canada).
  • Heavy metal content and crystalline silica dust exposure during handling.

7.3 Enhanced rock weathering for carbon removal

  • Mechanism: silicate weathering converts CO2 to bicarbonate; claims of carbon removal credits.
  • Key research: Leverhulme Centre for Climate Change Mitigation (University of Sheffield, David Beerling), Cornell/Illinois field trials, UC Davis and UC Merced trials, Yale Center for Natural Carbon Capture (verify).
  • Companies: Eion (US; Frontier offtake — verify), Lithos Carbon (US), UNDO (UK; verify status), Mati Carbon (India/Africa), InPlanet (Brazil), Terradot, Carbon Drawdown Initiative, Silicate (Ireland), Flux Carbon (Africa — verify).
  • Buyers and registries: Frontier (Stripe, Google, Shopify, and others), Microsoft purchases, Puro.earth and Isometric ERW protocols, Verra, Cascade Climate's ERW initiatives (verify).
  • MRV challenges: measuring weathering in open soils, downstream carbon loss, soil-based vs. water-based tracers.
  • Farmer-side questions: who pays for spreading, effects on pH and yield (some trials report yield gains in acidic soils — grade carefully), heavy metals (nickel, chromium in some basalts), and contract terms.

8. Biochar

8.1 Research topics

  • Production: pyrolysis temperature, feedstock (wood, crop residues, manure), kiln types (Kon-Tiki, Ring of Fire, retort, industrial pyrolysis). Equipment is covered in Part 04; here cover the material.
  • Properties: surface area, pH, ash content, H:Corg ratio (permanence indicator), PAH and dioxin testing.
  • Standards: International Biochar Initiative (IBI) Biochar Certified, European Biochar Certificate (EBC, including EBC-Agro and EBC-AgroOrganic classes), World Biochar Certificate, and the EU FPR component material category CMC 14 for pyrolysis materials (verify).
  • Organic status: NOP treats biochar based on feedstock and process (verify NOSB review and certifier practice); EU organic regulation additions of biochar as an allowed fertilizer (verify annex update date).
  • Charging/inoculating biochar with compost, urine, manure, or nutrients before application.
  • Application rates (from a few hundred kg/ha banded to 10+ t/ha broadcast) and cost realities.

8.2 Evidence leads

  • Meta-analyses: Jeffery et al. (2011 and 2017) on biochar yield effects showing larger benefits in tropical acidic, low-fertility soils and small or negative effects in temperate fertile soils (verify citations and effect sizes).
  • Schmidt et al. (2021) meta-analysis of biochar in agriculture (verify).
  • Research on biochar in livestock feed and bedding followed by field application (cascade use).
  • Biochar carbon removal (BCR) credits: Puro.earth, Isometric, Verra VM0044 (verify), and buyers such as Microsoft.

8.3 Seed companies (verify)

  • Wakefield BioChar (US), Biochar Now, Pacific Biochar (California), Oregon Biochar Solutions, Carbon Cycle Energy, Airex Energy (Canada), Pyreg (Germany), Carbofex (Finland), Exomad Green (Bolivia; large credit supplier — verify), Aries Clean Technologies, Biochar Supreme, Cool Planet (historical failure — verify), Rainbow Bee Eater (Australia), NetZeroNitrogen, Carbon Gold (UK).

9. Biofertilizers and microbial inoculants

9.1 Categories

  • Rhizobia for legumes (well established; Grade A for many legumes in soils lacking the right strain).
  • Free-living and associative nitrogen fixers claimed for non-legume crops.
  • Arbuscular mycorrhizal fungi (AMF) and ectomycorrhizal products.
  • Phosphate-solubilizing and potassium-mobilizing bacteria.
  • Bacillus, Pseudomonas, Azospirillum, Trichoderma, and multi-strain consortia.
  • "Effective Microorganisms" (EM, EM-1 from EMRO, Teruo Higa) and similar lactic-acid-bacteria/yeast blends.

9.2 Seed products and companies (verify)

  • Rhizobia: Novonesis (formed from Novozymes and Chr. Hansen merger in 2024 — verify) TagTeam and JumpStart; BASF Nodulator; Verdesian (Guard-N, verify); Advanced Biological Marketing; XiteBio (Canada); Legume Logic.
  • N-fixing for cereals: Pivot Bio (PROVEN 40, RETURN — verify product names and claimed N replacement; grade independent university trials separately), Azotic Technologies (Envita, Gluconacetobacter diazotrophicus — verify), Kula Bio, Corteva Utrisha N (Methylobacterium symbioticum foliar product — verify), Sound Agriculture Source (synthetic chemistry, not microbial — verify), Joyn Bio (Ginkgo/Leaps by Bayer joint venture; status verify).
  • Mycorrhizae: MycoApply (Valent BioSciences/Mycorrhizal Applications), Mykos (Xtreme Gardening), Plant Success, Great White (Plant Revolution), Rootgrow (PlantWorks UK), Symbiom (Czech Republic), Mycorrhizal Applications, AM 120 (Reforestation Technologies International).
  • Multi-strain and Bacillus: Pathway Biologic, Holganix, Terramera (verify), BioWorks (acquired by Biobest — verify), AgBiome (assets sold — verify 2024–2025 status), Indigo Ag (biologicals plus carbon program; verify current focus), Marrone Bio (acquired by Bioceres Crop Solutions in 2022 — verify), Andermatt, Koppert, Lallemand Plant Care, Symborg (acquired by Corteva in 2022 — verify), Stoller (acquired by Corteva in 2023 — verify), Biotalys, Aphea.Bio (Belgium), Groundwork BioAg (Israel), Loveland Products, Kiverdi / Air Protein spinoffs (verify).
  • Big-company biological divisions: Bayer (partnership pipeline), Syngenta Biologicals (including Valagro and Biographica acquisitions — verify), Corteva Biologicals, BASF, FMC, UPL NPP (Natural Plant Protection), Sumitomo Chemical/Valent BioSciences, Novonesis.

9.3 Research topics and evidence

  • Colony-forming unit (CFU) claims, viability over shelf life, strain identification, and independent testing results (for example, studies showing many commercial mycorrhizal products contained no viable propagules — verify Salomon et al. 2022 and related work).
  • Meta-analyses of AMF inoculation in the field (for example, work led by Hart, Antunes, or Koziol — verify) and the role of native AMF populations and tillage/fallow.
  • University trials of Pivot Bio and similar products in the US Corn Belt (Iowa State, University of Illinois, University of Wisconsin, University of Nebraska — verify results and grade).
  • Why microbial products work inconsistently: soil competition, application method, temperature, fungicide seed treatments, and existing nutrient levels.
  • Regulatory status in the US: microbial fertilizers regulated by states; pesticidal microbes by EPA; the Plant Biostimulant Act (bills introduced in 2019, 2021, 2023, 2025 — verify status in the 119th Congress) and AAPFCO "beneficial substances" model bill and uniform labeling.
  • EU FPR 2019/1009 component category CMC 7 (microorganisms) currently limited to a short list of genera (Azotobacter, mycorrhizal fungi, Rhizobium, Azospirillum — verify any expansion).

10. Biostimulants

  • Definitions: EBIC and EU FPR definition (function-based, not composition-based); US Farm Bill 2018 definition and EPA's 2019 draft guidance on plant regulator claims (verify final status).
  • Categories: humic and fulvic acids (leonardite-derived), seaweed and kelp extracts (Ascophyllum nodosum, Ecklonia maxima), protein hydrolysates and amino acids (animal- vs. plant-derived), chitosan, silicon, phosphites (not allowed in NOP organic — verify), microbial biostimulants.
  • Seed brands (verify): Acadian Plant Health (Stimplex, Acadian), Kelpak, Maxicrop, Tradecorp, Valagro (Syngenta), Biolchim, Italpollina (Trainer, Hello Nature), Isagro (acquired by Gowan — verify), Huma Gro (Bio Huma Netics), Actagro (Nutrien — verify), BioAg, Agrinos (status verify), Omnia, Plant Food Company, Earthworm Technologies, Humic Growth Solutions, Black Earth Humic (Canada), Live Earth Products.
  • Evidence: meta-analyses of biostimulant effects on yield (for example, Li et al. 2022 in Scientia Horticulturae or similar — verify), abiotic stress trials, frequency of positive vs. null results, publication bias.
  • Economics: cost per acre vs. average yield benefit; when a small percentage gain pays off on high-value crops but not grain.
  • Market data: biostimulant market size estimates (flag that market research firm numbers vary widely and are often not verifiable; grade D or E).

11. Farm-made and fermented inputs

  • Bokashi (fermenting food waste or bran with EM or lactic acid bacteria).
  • Korean Natural Farming (KNF, Cho Han-kyu): Indigenous Microorganisms (IMO 1–5), Lactic Acid Bacteria Serum (LABS), Fermented Plant Juice (FPJ), Oriental Herbal Nutrient (OHN), Water-Soluble Calcium (WCA), Fish Amino Acid (FAA), JADAM (Youngsang Cho) and JMS (JADAM Microbial Solution).
    • Research leads: University of Hawaiʻi CTAHR publications on KNF (verify), Hawaii Natural Farming groups, and trials in the Philippines, Thailand, and Korea.
    • Certification check: NOP status of homemade inputs (generally allowed if all ingredients comply; OHN uses alcohol — check certifier), food-safety concerns with fish and animal-based ferments.
  • Biodynamic preparations 500–508 and Demeter requirements; evidence from DOK trial and meta-analyses of biodynamic practices (verify Brock et al. or similar review).
  • Johnson-Su bioreactor compost and extracts.
  • Liquid manures and plant teas (comfrey, nettle).
  • Wood vinegar (pyroligneous acid) as input and pest product (check regulatory status — may make pesticidal claims).
  • Deliverable: a farm-made input safety and compliance table (ingredients, pathogen risk, organic compliance, evidence grade).

12. Cover crops and green manures as fertility inputs

  • This part covers cover crop seed as a purchased input; practices and termination equipment are in Parts 04–05.
  • Legume N contribution estimates (hairy vetch, crimson clover, field pea, fava) and methods to estimate (for example, the Cover Crop Nitrogen Calculator from Oregon State; the NRCS/PSA Cover Crop N Calculator; Midwest Cover Crops Council selector tools — verify names).
  • Cover crop seed suppliers (verify): Albert Lea Seed, Green Cover Seed, Kings AgriSeeds, Hancock Seed, Johnny's, Fedco, La Crosse Seed, Welter Seed, Cotswold Seeds (UK), Deleplanque/Jouffray-Drillaud (France).
  • Organic seed availability and the NOP commercial availability rule; SOE and seed sourcing documentation.
  • Cover crop seed price trends 2019–2026 and cost per acre by mix.
  • Evidence: meta-analyses on cover crops and yield (for example, Abdalla et al. 2019; Tamburini et al. 2020; Poeplau and Don 2015 on soil carbon — verify) and US survey data (SARE/CTIC National Cover Crop Survey — verify latest year).

13. Mulch materials as soil inputs

  • Organic mulches for fertility and soil protection: straw, hay (seed and herbicide risk), wood chips (ramial chipped wood), leaves, cardboard (inks, tapes, glue — certifier rules), sawdust, arborist chips (ChipDrop and similar services — verify), and living mulches.
  • Plastic and biodegradable films are covered in Part 03.
  • Nitrogen immobilization, weed seed contamination, and allelopathy concerns.
  • Evidence on wood chip mulch in orchards, vegetable systems, and "Back to Eden" gardening (grade the viral claims separately).

14. Biosolids, sewage sludge, and residual products

  • NOP prohibition on sewage sludge (7 CFR 205.105) and conventional use of Class A/B biosolids.
  • PFAS: Maine's 2022 ban on biosolids land application and its farm impacts and relief fund (verify); Michigan industrial pretreatment program and farm closures; Texas lawsuits involving Synagro-supplied biosolids (verify 2024–2025 cases); EPA's January 2025 draft sewage sludge risk assessment for PFOA and PFOS (verify status under current administration); state actions in Connecticut, Minnesota, New York, and others (verify).
  • Biosolids-based fertilizer brands: Milorganite (Milwaukee), Synagro products, Oceangro, Bay State Fertilizer (Boston), Tagro (Tacoma), Loop (King County). Record PFAS testing statements.
  • Compost PFAS: detections in food-waste composts using certain "compostable" packaging; state bans on PFAS in food packaging; BPI certification requirements for fluorine limits (verify).
  • Other residuals: digestate from anaerobic digesters (organic status varies), paper mill sludge, food processing residuals, mushroom compost, spent brewing grain.

15. Contaminants and testing

15.1 Contaminant categories

  • Heavy metals: cadmium in rock phosphate (EU FPR cadmium limits of 60 mg/kg P2O5 — verify), lead and arsenic in some composts and ash, zinc and copper in manures.
  • Persistent herbicides: aminopyralid, clopyralid, picloram, aminocyclopyrachlor, fluroxypyr; bioassay methods (pea or bean test).
  • PFAS and fluorinated compounds.
  • Physical contaminants: plastics and glass in municipal composts; EU and UK limits on physical impurities.
  • Pathogens: E. coli O157:H7, Salmonella, Listeria.
  • Pharmaceuticals and antibiotic resistance genes.
  • Pesticide residues in feedstocks (for example, cottonseed meal, conventional hay).

15.2 Testing resources to verify

  • Soil and compost labs: Penn State Agricultural Analytical Services Lab, UMass Soil and Plant Nutrient Testing Lab, Cornell Soil Health Lab, A&L Laboratories, Waypoint Analytical, Logan Labs, Ward Laboratories, Midwest Laboratories, Brookside Laboratories, Agvise, NRM (UK), Eurofins Agro (Netherlands). (Soil testing detail is in Part 07.)
  • PFAS testing in soil and compost: state-certified labs, costs per sample, detection limits, and the difficulty of interpreting results without standards.
  • Persistent herbicide lab testing vs. home bioassay.

16. Rates, timing, and cost per acre

  • Build tables for 30–50 common materials showing: typical nutrient content, typical rate per hectare and per acre (and per 100 sq ft bed for gardeners), timing relative to planting, price per unit (with date and region), cost per unit of N, P2O5, and K2O, and notes on release rate.
  • Show at least three regional price examples (for example, US Northeast, California, UK, and one Global South market such as Kenya or India).
  • State clearly that prices change quickly and must be verified with current supplier quotes.

17. Case studies to investigate (verify)

  • A market garden replacing purchased fertilizers with on-farm compost and cover crops (look at SARE farmer grants).
  • Grain farm adopting Pivot Bio or similar N-fixing microbes: claimed vs. independent trial results.
  • A biochar producer supplying farms and selling carbon removal credits.
  • An ERW project paying farmers to spread basalt (for example, in the US Midwest, UK, Brazil, or India).
  • A fertilizer fraud case and how growers were affected.
  • A farm affected by PFAS in biosolids (Maine, Michigan, or Texas) and the policy response.
  • A persistent herbicide compost contamination incident at a commercial compost facility.
  • A biological input startup that failed or was sold for parts.

Deliverables for Part 01

  • Soil fertility materials guide in plain language (one section per material category).
  • At least 150 input product records with claimed vs. measured fields.
  • Evidence and claims table for compost, compost tea, manures, organic fertilizers, rock dust/ERW, biochar, inoculants, biostimulants, and farm-made inputs, using Part 00 grades.
  • Nutrient content and cost-per-unit-nutrient table with price dates.
  • Contamination and recall event list (2019–2026) with regulation records.
  • Certification status summary for each material category under NOP, EU, UK, and Canada.
  • Sourcing checklist for compost, manure, hay, straw, and wood chips.
  • Farm-made input safety and compliance table.
  • Company database (at least 40 records), with M&A and status notes.
  • Open questions and conflicting evidence list.

Research standards

  • Record the exact date of research and every access date.
  • Treat all named brands, companies, studies, and rules as leads to verify.
  • Prefer primary sources: NOP regulations and guidance, OMRI/WSDA/CDFA listings, EU and national regulators, peer-reviewed meta-analyses, long-term trials, extension publications, and court or enforcement records.
  • Record study funders and whether results came from field, greenhouse, or lab work.
  • Separate soil-test changes, yield effects, economic returns, and environmental outcomes.
  • Note how results vary by soil texture, pH, climate, crop, and scale.
  • Report fraud and contamination cases carefully, using official records and naming outcomes accurately (charges, settlements, dismissals).
  • Always advise farmers to check inputs with their certifier before use.
  • Cover inputs used by smallholders and Global South farmers, not only US and EU products.