{
    "name": "Manure Application Rate Calculator",
    "url": "https://calculators.geekmidst.com/calculators/manure-application-rate-calculator",
    "markdown": "https://calculators.geekmidst.com/calculators/manure-application-rate-calculator.md",
    "category": "Agriculture",
    "description": "Find the manure or slurry rate that supplies a nutrient target, from the manure’s nutrient content and first-year availability, in t/ha, tons/acre or gal/acre.",
    "summary": "Divide the nutrient the crop needs by the plant-available nutrient in each tonne (or cubic metre) of manure to get the application rate.",
    "also_called": [
        "Slurry rate calculator",
        "Manure nutrient calculator"
    ],
    "applies_to": "Worldwide",
    "last_updated": "2026-10-29",
    "computation": "Results are computed in the visitor’s browser on the HTML page. This API describes the calculator; it does not compute results.",
    "inputs": [
        {
            "name": "need",
            "label": "Nutrient to supply",
            "type": "number",
            "default": "100"
        },
        {
            "name": "need_basis",
            "label": "Target unit",
            "type": "segmented",
            "default": "kg_ha",
            "options": {
                "kg_ha": "kg/ha",
                "lb_acre": "lb/acre"
            }
        },
        {
            "name": "content",
            "label": "Nutrient content of the manure",
            "type": "number",
            "default": "6"
        },
        {
            "name": "content_unit",
            "label": "Content unit",
            "type": "select",
            "default": "kg_t",
            "options": {
                "kg_t": "kg per tonne (solid)",
                "lb_ton": "lb per US ton (solid)",
                "kg_m3": "kg per m³ (liquid)",
                "lb_1000gal": "lb per 1,000 US gal (liquid)"
            }
        },
        {
            "name": "availability",
            "label": "Available in the first year",
            "type": "number",
            "default": "40",
            "unit": "%"
        },
        {
            "name": "area",
            "label": "Field area",
            "type": "number",
            "default": "2"
        },
        {
            "name": "area_unit",
            "label": "Area in",
            "type": "segmented",
            "default": "ha",
            "options": {
                "acre": "Acres",
                "ha": "Hectares"
            }
        }
    ],
    "outputs": [
        {
            "key": "rate_ha",
            "label": "Rate per hectare (t or m³)",
            "format": "number"
        },
        {
            "key": "rate_acre",
            "label": "Rate per acre (t or m³)",
            "format": "number"
        },
        {
            "key": "rate_us",
            "label": "Rate per acre (US tons or US gal)",
            "format": "number"
        },
        {
            "key": "total",
            "label": "Manure for the field (t or m³)",
            "format": "number"
        },
        {
            "key": "summary",
            "label": "In words",
            "format": "text"
        }
    ],
    "formula": {
        "text": "Rate = Nutrient target ÷ (Nutrient content × Availability %);  Total = Rate × Area",
        "variables": {
            "Nutrient content": "kg per tonne or per m³ (lb/US ton × 0.5 = kg/t; lb/1000 gal × 0.1198 = kg/m³)",
            "Availability": "first-year plant-available fraction"
        }
    },
    "worked_example": {
        "inputs": {
            "need": "100",
            "need_basis": "kg_ha",
            "content": "6",
            "content_unit": "kg_t",
            "availability": "40",
            "area": "2",
            "area_unit": "ha"
        },
        "steps": [
            "Available N = 6 kg/t × 0.40 = 2.4 kg per tonne.",
            "Rate = 100 ÷ 2.4 = 41.67 t/ha (16.86 t or 18.59 US tons per acre).",
            "For 2 ha: 83.33 t."
        ],
        "result": "To supply 100 kg/ha of available N from manure with 6 kg N/t at 40% availability, spread about 42 t/ha, 83 t on 2 ha."
    },
    "interpretation": "Manure rarely matches crop needs for every nutrient. Check the P and K this rate supplies and top up the shortest nutrient with mineral fertiliser rather than adding more manure.",
    "assumptions": [
        "Nutrient content is per unit of manure as spread (fresh weight)."
    ],
    "limitations": [
        "Local rules may cap manure or nitrogen rates (for example, in nitrate-vulnerable zones); check them before spreading.",
        "Availability figures are estimates that vary with timing and incorporation."
    ],
    "rules": null,
    "faqs": [
        {
            "question": "Why include availability?",
            "answer": "Much of the nitrogen in manure is organic and only becomes available over several seasons, so only part counts towards this crop."
        },
        {
            "question": "Should I base the rate on N or P?",
            "answer": "Where phosphorus builds up in soil, advisers often recommend rating manure on P and supplying the extra N from fertiliser."
        }
    ],
    "sources": [],
    "related": [
        {
            "name": "Fertiliser Application Rate Calculator",
            "url": "https://calculators.geekmidst.com/calculators/fertilizer-application-rate-calculator"
        },
        {
            "name": "Fertiliser NPK Calculator",
            "url": "https://calculators.geekmidst.com/calculators/fertilizer-npk-blend-calculator"
        },
        {
            "name": "Compost Volume Calculator",
            "url": "https://calculators.geekmidst.com/calculators/compost-volume-calculator"
        }
    ],
    "disclaimer": null,
    "publisher": "GM¹X CalcVerse"
}