Nutrient Use Efficiency & Is Your Fertiliser Working?
Measures AE
Enter fertilised and unfertilised yields and the nutrient applied to get agronomic efficiency, partial factor productivity and recovery efficiency — see how much crop each kilo of fertiliser is buying.
Enter your trial
Next: low AE means N is being lost — split the dose, place it in the root zone, and correct any other limiting nutrient before adding more.
AE, PFP and RE are the standard IPNI / FAO nutrient-use-efficiency metrics: AE = (yield with − without) ÷ nutrient applied; PFP = yield ÷ nutrient; RE = extra uptake ÷ nutrient applied.
Nutrient use efficiency — key facts
- Agronomic efficiency
- (Yf − Y0) ÷ nutrient
- Partial factor prod.
- Yf ÷ nutrient
- Recovery efficiency
- uptake gain ÷ applied × 100
- Good AE (N)
- 15–25 kg grain / kg N
- Good RE (N)
- 40–60% recovered
- Improve it
- right rate, time, place, source
- Low AE
- losses or another limiting factor
- Privacy
- Runs in your browser; nothing uploaded
Fertiliser is money — make every kilo count
Fertiliser is one of the biggest cash costs in farming, and much of it can be lost before the crop ever uses it. Nutrient use efficiency tells you how much of that spend is turning into grain. By comparing a fertilised area with an unfertilised control and dividing the yield gain by the nutrient applied, you get a hard number for how well your nutrient programme is working — and a baseline to improve.
This tool computes agronomic efficiency, partial factor productivity, recovery efficiency and physiological efficiency, and bands the result so you know whether it's low, moderate, good or high. Use it to justify splitting doses, fixing a limiting nutrient, or cutting an over-application. Pair it with the Fertilizer (NPK), Crop Nutrient Removal and Soil Organic Carbon tools to build an efficient, profitable nutrient plan.
Benchmark your fertiliser
Turn a control strip into a hard efficiency number.
Spot the losses
Low AE or RE flags nutrient leaving before uptake.
Justify the 4Rs
Prove that better timing and placement pay.
Track over years
PFP is easy to log every season to show progress.
Frequently Asked Questions
What is nutrient use efficiency?+
Nutrient use efficiency (NUE) measures how much extra crop you get for each unit of nutrient you apply. The most useful field measures are agronomic efficiency (AE), partial factor productivity (PFP) and apparent recovery efficiency (RE). Higher values mean less nutrient is wasted to leaching, runoff or volatilisation.
What is agronomic efficiency (AE)?+
AE = (yield with fertiliser − yield without) ÷ nutrient applied. It is the extra kilograms of crop per kilogram of nutrient added. For nitrogen on cereals, AE of 15–25 kg grain per kg N is good; below about 8 means much of the nutrient is being lost or another factor is limiting yield.
What is partial factor productivity (PFP)?+
PFP = total yield with fertiliser ÷ nutrient applied. Unlike AE it doesn't subtract the unfertilised yield, so it reflects the whole system's productivity per unit of nutrient. It is easy to track over years because it only needs your yield and the rate applied.
What is apparent recovery efficiency (RE)?+
RE = (nutrient uptake with fertiliser − uptake without) ÷ nutrient applied × 100. It is the percentage of applied nutrient the crop actually took up. For nitrogen, 40–60% is good field performance; low RE points to losses you can fix with better timing, placement and splitting.
Why is my agronomic efficiency low?+
Common causes: too much nutrient applied at once, poor timing (not matched to crop demand), surface application that volatilises or runs off, and another limiting factor (water, a different nutrient, pH, pests). Fixing the limiting factor or splitting the dose usually lifts AE more than adding more fertiliser.
How do I improve nutrient use efficiency?+
Follow the 4Rs: Right source, Right rate, Right time and Right place. Split nitrogen to match crop demand, place it in the root zone, correct soil pH and other nutrients first, and add organic matter. Re-run this calculator each season to confirm AE and RE are rising.
What yields and units should I enter?+
Enter the yield from a fertilised area and from an unfertilised (control) strip in the same unit (kg), plus the amount of the nutrient applied over the same area in kg. The calculator divides them, so as long as the area basis matches, the metrics are correct.
What is physiological efficiency (PE)?+
PE = yield gain ÷ uptake gain — the extra crop produced per unit of extra nutrient the plant took up. It separates how well the plant USES the nutrient inside it from how well it RECOVERS it from the soil. Low PE with high RE means the plant takes up nutrient but can't convert it to yield (often another limiting factor).
Does higher NUE mean more profit?+
Usually yes, because you get more crop per unit of an expensive input and lose less to the environment. But the economic optimum rate is often slightly below the maximum-yield rate — use NUE alongside a margin check to find the rate that pays best, not just the one that yields most.
Are these standard metrics?+
Yes — AE, PFP, RE and PE are the internationally recognised nutrient-use-efficiency indicators used by IPNI/IFA, FAO and agronomy researchers to benchmark fertiliser performance and guide the 4R nutrient stewardship framework.