FYM Fertilizer Equivalent & Manure's N-P-K Value
Credits urea
Enter the tonnes of farmyard manure or compost and its N-P-K to get the urea, DAP and MOP equivalentit supplies — so you can cut bagged fertiliser and build your soil.
Enter your manure
Next: credit ~32.6 kg urea, 99.6 kg DAP and 100 kg MOP from 10 t of FYM, and reduce your fertiliser order accordingly.
Only part of FYM's N is available the first year (availability %); P and K are mostly available; test your manure for actual content.
FYM value — key facts
- Year-1 N
- tonnes × N% × availability
- Availability
- ≈ 30% of N in year one
- P & K
- mostly available year one
- Urea-eq
- available N ÷ 0.46
- DAP
- 46% P₂O₅
- MOP
- 60% K₂O
- Builds
- organic matter & soil structure
- Privacy
- Runs in your browser; nothing uploaded
Your manure is fertiliser — count it
Farmyard manure and compost are not just bulk for the soil — they carry real nitrogen, phosphorus and potassium. The catch is timing: most of the nitrogen releases slowly, so only about a third is available in the first year, while phosphorus and potassium come good almost in full. Crediting that nutrient value against your fertiliser plan lets you buy fewer bags and build organic matter, structure and microbial life at the same time.
This tool converts your manure into bagged-fertiliser terms — the available N, P₂O₅ and K₂O, plus the urea, DAP and MOP equivalent — from the tonnes and N-P-K you enter. Subtract those equivalents from your crop's requirement and buy only the shortfall. Pair it with the Manure Application Rate, Compost & Manure and NPK from Fertilizer Grade tools to plan and credit in one go.
Credit the nutrients
Count the N-P-K your manure already supplies.
Cut bagged fertiliser
Buy only the shortfall after the manure credit.
Build the soil
Organic matter and structure on top of the NPK.
Think in bags
Urea, DAP and MOP equivalent in kilograms.
Frequently Asked Questions
What is the FYM fertilizer equivalent?+
It is the amount of bagged fertiliser — urea, DAP and MOP — that the nitrogen, phosphorus and potassium in your farmyard manure or compost can replace. Manure carries real N-P-K value, so counting it lets you cut how much fertiliser you buy and build soil organic matter at the same time, instead of treating the manure as worthless bulk.
How is the nutrient value of manure calculated?+
Year-1 available nitrogen = tonnes × N% × availability factor (about 30%, since most manure N mineralises slowly). Phosphorus and potassium are mostly plant-available in the first year, so they are credited in full. Urea-equivalent = available N ÷ 0.46, because urea is 46% N. The tool does the same for DAP (P₂O₅) and MOP (K₂O).
Why only about 30% of the nitrogen in year one?+
Manure nitrogen is largely held in organic compounds that soil microbes release slowly over several seasons. Only roughly a third becomes plant-available in the first year; the rest carries over and improves later crops. P and K are more readily available, which is why they are credited closer to their full content.
What N-P-K should I enter for my manure?+
Well-rotted farmyard manure is often around 0.5% N, 0.25% P₂O₅ and 0.5% K₂O on a fresh-weight basis, but it varies hugely with animal, bedding, age and storage. Compost and poultry manure differ again. Use a lab analysis if you have one; otherwise start from typical values and adjust as you learn your source.
How do I turn the value into urea, DAP and MOP?+
Divide the available nutrient by the grade of the bagged product: urea is 46% N, DAP supplies 46% P₂O₅ (and some N), and MOP is 60% K₂O. The tool reports the urea-equivalent, DAP-equivalent and MOP-equivalent kilograms so you can subtract them from your fertiliser plan directly.
Can I cut my bagged fertiliser by the full equivalent?+
Largely yes — credit the manure's available nutrients against your crop's requirement and buy only the shortfall. Keep a little buffer for variability, and remember the slow-release nitrogen pays back in later seasons. Over years, regular manuring lowers fertiliser need further as soil fertility and structure improve.
Does manure do more than supply N-P-K?+
Yes — it adds organic matter, feeds soil microbes, improves water-holding and structure, and supplies sulphur and micronutrients that bagged NPK lacks. The fertiliser equivalent only counts the major nutrients, so the real agronomic value of manure is higher than the N-P-K credit alone.
Does it work for compost and any area or weight unit?+
Yes — enter the tonnes (or convert your trailer loads to tonnes) and the N-P-K of farmyard manure, compost, vermicompost or poultry litter. The calculation is the same; only the nutrient percentages and availability change. Set them to match your material for a realistic credit.
Are the figures exact?+
They are sound planning figures. Real availability depends on manure type, how well it is rotted, soil temperature, moisture and timing of application. Test your manure where you can, apply it evenly and incorporate it promptly to limit losses, and treat the equivalents as a guide for trimming your fertiliser bill.
How is this different from a manure application rate calculator?+
An application rate tool tells you how many tonnes to spread to hit a target nutrient or rate; this one works the other way — it credits the fertiliser value of the manure you have. Use them together: see the Manure Application Rate and Compost & Manure calculators to plan and credit in one workflow.