Reference Tables & Conversions
The numbers scattered through the almanac, gathered into one place: conversions, target ranges, sanitation thresholds, rates, analysis values, and limits. Each table links back to the chapter that explains it — print this page and keep it in the truck.
Units & conversions
The almanac writes in metric first and gives imperial equivalents because both are in daily use. The rate calculator does these conversions for you — these are the factors it applies.
| Quantity | From → to | Multiply by |
|---|---|---|
| Application rate | t/ha → US ton/acre | 0.446 |
| Application rate | US ton/acre → t/ha | 2.242 |
| Nutrient rate | kg/ha → lb/acre | 0.892 |
| Nutrient rate | lb/acre → kg/ha | 1.121 |
| Bulk density | kg/m³ → lb/yd³ | 1.685 |
| Volume | m³ → yd³ | 1.308 |
| Blower power | kW → hp | 1.341 |
| Static pressure | kPa → in. w.g. | 4.02 |
| Rainfall | mm → L/m² | 1 |
| Temperature | °C → °F | × 9/5 + 32 |
| °C | °F | Why this one matters |
|---|---|---|
| 40 | 104 | Above the mesophilic optimum — thermophiles begin to take over |
| 45 | 113 | Bottom of the thermophilic band |
| 55 | 131 | The sanitation threshold every standard is built on |
| 65 | 149 | Top of the ideal active-phase band for most farm piles |
| 70 | 158 | Enzymes start denaturing; turn to shed heat |
| 71 | 160 | Microbial activity falls away; spontaneous combustion becomes conceivable in large dry piles |
| 77 | 171 | NOP upper bound for raw-manure compost |
Process targets
Everything here is measurable with a thermometer, a handful of material, and a notepad. Full explanations in Process Control and The Science.
| Variable | Target | Failure mode on either side |
|---|---|---|
| Initial C:N | 25:1–40:1 (≈30:1) | Below ~20:1 ammonia loss · above ~40:1 slow, cool pile |
| Moisture | 50–60% (65–75% for strawy mixes) | Below 40% stalls · above 65% pore space floods, anaerobic |
| Pore-space oxygen | Above 5% (10%+ comfortable) | Below 5% odor compounds, CH₄ and N₂O form within hours |
| Free air space | Above 30% | Below 30% diffusion limits oxygen delivery |
| Core temperature | 55–65 °C in the active phase | Above 70–75 °C enzymes denature · below 45 °C little sanitation |
| Bulk density | 350–550 kg/m³ | Too dense seals pores · too light cannot insulate |
| Pile size | At least ~1 m³ (1 m high); windrows 2–3 m high | Small piles freeze or cool · above ~3 m convection fails |
| pH | Starts 5.5–7.5, finishes 6.5–8.0 | Below 5.5 usually means anaerobic · above 8.5 watch ammonia and lime-sensitive crops |
| Turning (windrow) | Weeks 1–4 every 7–10 days; weeks 5–8 every 2–3 weeks; then as needed | Calendar turning instead of trigger turning wastes labour or misses heat peaks |
| Finished C:N | ≤20:1 (10–15:1 ideal) | Above ~25:1 risks nitrogen tie-up in soil |
| Product moisture | 35–50% at sale | Wetter product means paying to haul water |
Time & temperature
Sanitation follows sustained heat at the coldest part of the pile, not a momentary peak. Organism figures are indicative; process standards are the numbers you document. See Quality & Standards.
| Standard / organism | Temperature | Holding time |
|---|---|---|
| NOP raw-manure compost (initial C:N 25–40:1) | 55–77 °C | 15 days with at least 5 turnings, or ASP equivalent |
| EPA 503 PFRP — in-vessel or static aerated pile | 55 °C | 3 days |
| EPA 503 PFRP — windrow | 55 °C | 15 days with at least 5 turnings |
| PAS 100 (UK) | Minimum 60 °C hygiene phase | Defined turn or aeration regime |
| EU fertilising products / national end-of-waste | Commonly 60–65 °C | National process rules |
| Salmonella spp. | 55 °C hours to days; 60 °C minutes to hours | — |
| E. coli O157:H7 | Similar to Salmonella | Sensitive to sustained 55 °C+ |
| Listeria monocytogenes | Reduced at 55–60 °C | Regrowth risk if re-contaminated while cooling |
| Ascaris (helminth) ova | Sustained ~55 °C | Days — among the most heat-resistant |
| Most weed seeds | 55–60 °C | 3+ days; some hard-coated species survive |
| Most plant viruses & clubroot | Partially resistant | Some survive normal composting — rotate and wash down equipment |
Application rates & timing
Rates are as-applied unless stated dry. Cap the long-term rate by soil-test phosphorus, and confirm intervals with your certifier or nutrient-management plan. Full detail in Field Application.
| Crop or use | Typical rate | Notes |
|---|---|---|
| Field crops & cereals (maintenance) | 2–6 t/ha dry matter (≈10–30 t/ha as applied) | Adjust for soil OM, P status, and crop |
| Vegetables & intensive horticulture | 20–40 t/ha before heavy feeders; 10–20 t/ha for follow-on crops | Banding or in-row placement at 1/3–1/2 the broadcast rate |
| Orchards & vineyards | 10–30 t/ha every 1–3 years | Composted mulch 5–10 cm deep under the drip line |
| Pasture & forage | 10–20 t/ha | Harrow to scatter lumps; watch grazing intervals for parasite carryover |
| Container media & nurseries | 10–30% by volume | Test every batch for germination and EC — containers amplify salts |
| One-time soil remediation | 50–100 t/ha | Incorporated full depth; expect the response in years 2–4 |
| Timing rule | Value |
|---|---|
| Best window | Just before planting or during main tillage; fall for spring crops on well-drained soils |
| Incorporate within | 24–48 hours where possible |
| Never spread on | Frozen, snow-covered, saturated, or standing-water ground |
| Buffer to watercourses | 25 m+ (more where locally required) |
| Buffer to tile inlets | 10 m (US NRCS guidance) |
| NOP raw-manure interval | 120 days before harvest of soil-contact crops; 90 days for non-contact. Compost made to NOP standard is exempt |
What compost supplies
First-year availability for a typical manure-based compost. It is a soil conditioner first and a nutrient source second — see Field Application and Benefits.
| Nutrient | First-year availability | Notes |
|---|---|---|
| Nitrogen | ~10–40% | Slow-release across years; expect to supplement high-N demand crops |
| Phosphorus | ~50–80% | Builds soil P steadily — the main reason to cap rates by soil test |
| Potassium | ~80–100% | Behaves close to mineral K |
| Calcium / magnesium | High | Often-underrated liming and conditioning value (compost pH 7–8) |
| Micronutrients | Broad spectrum | Chelated by humic substances over time |
Reading an analysis
What a good compost analysis looks like, and what each line means. Sampling method matters as much as the lab — see Getting a lab test.
| Parameter | Typical good compost | What it means |
|---|---|---|
| Moisture | 30–50% | Handling and transport value; too wet means shipping water |
| Organic matter | 30–50% of dry weight | The core value proposition |
| C:N ratio | ≤20:1 (10–15:1 ideal) | Above ~25:1 risks N tie-up in soil |
| Total N | 1–2.5% (dry) | Roughly 10–40% mineralizes in year 1 |
| pH | 6.5–8.0 | Above 8.0, watch lime-sensitive crops |
| EC (soluble salts) | 2–6 mmhos/cm | High values restrict container and seedling use |
| Solvita / respiration | Index 6–8 | Stability — will not reheat or rob soil oxygen |
| Germination index | ≥90% | Maturity — safe for seedlings |
| Fecal coliform | Below 1,000 MPN/g | Class A-equivalent sanitation |
| Salmonella | Not detected (below 3 MPN/4 g) | Sanitation |
Metal reference ceilings
mg/kg dry weight. Limits differ by jurisdiction and product class; these are commonly cited ceilings for comparably strict classes. Metals are an input problem — clean feedstocks almost never approach them. See Metals & limit values.
| Metal | US EPA EQ (sludge) | EU (indicative A) | PAS 100 (UK) | Canada Cat. A |
|---|---|---|---|---|
| Arsenic (As) | 41 | 10 | 25 | 13 |
| Cadmium (Cd) | 39 | 0.7–1.5 | 1.5 | 3 |
| Chromium (Cr) | 1,200 (total) | 70–100 | 100 | 210 |
| Copper (Cu) | 1,500 | 70–200 | 200 | 400 |
| Mercury (Hg) | 17 | 0.4–1 | 1 | 0.8 |
| Nickel (Ni) | 420 | 25–50 | 50 | 62 |
| Lead (Pb) | 300 | 45–120 | 200 | 150 |
| Zinc (Zn) | 2,800 | 200–400 | 400 | 700 |
Indicative reference ceilings drawn from public standards (40 CFR 503 Table 3, EU 2019/1009 module, PAS 100:2018, CCME Category A). Ranges reflect product classes within a jurisdiction. Educational context, not regulatory guidance — obtain your own governing standard's tables before making product decisions.
Leachate parameters
What the liquid leaving a compost pad carries, and why it is regulated. See Water & Leachate.
| Parameter | Typical fresh leachate | Why it matters |
|---|---|---|
| BOD₅ | 2,000–20,000+ mg/L | Oxygen demand in receiving water; fish-kill driver |
| Ammonia-N | 100–2,000+ mg/L | Aquatic toxicity (un-ionized NH₃), algal growth |
| Total phosphorus | 10–500 mg/L | Eutrophication; often the binding permit limit |
| Soluble salts (EC) | 10–40+ dS/m | Blows up soil salinity if land-applied ungauged |
| Suspended solids | 1,000–10,000 mg/L | Turbidity, sediment, phosphorus sorbed to particles |
| Heavy metals | Usually low with clean feedstocks | Concentrate in drying residue; test with biosolids inputs |
Mass balance & shrink
What a tonne of feedstock becomes. These are the numbers that decide pad size, hauling cost, and whether a shrink claim makes sense. See Mass & moisture accounting.
| Change | Typical | Why |
|---|---|---|
| Dry-matter loss | 40–70% | Respired to CO₂ and water; nutrients and minerals stay and concentrate |
| Wet mass loss | 30–60% | Dry-matter loss plus evaporation |
| Volume loss | 40–60% | Structure collapses; sets pad area and storage needs |
| Rule of thumb | 2–3 wet t feedstock → ~1 wet t compost | Planning figure for manure-type feedstocks |
| Finished C:N | 10:1–20:1 | Carbon leaves as CO₂ faster than nitrogen leaves as gas |