Nutrient Use Efficiency Calculator

Agronomic Efficiency divides only the yield increase attributable to fertilizer (fertilized yield minus unfertilized yield) by N applied, isolating fertilizer's marginal payoff. Partial Factor Productivity divides the entire fertilized yield by N applied, so it also credits soil-supplied nitrogen, genetics, and weather — everything that contributed to that total yield, not just the fertilizer response. Because total yield is always at least as large as the response, PFP will always read higher than AE for the same field.

It backs out total plant biomass from grain yield divided by harvest index (biomass = grain ÷ harvest index), splits out the stover fraction as the remainder, then applies your entered grain N% and stover N% separately to each fraction and sums them. This is a standard agronomic approximation, but it's only as accurate as your harvest index and tissue-N percentage assumptions — both vary by hybrid, variety, and growing conditions.

It uses fixed placeholder prices baked into the calculation — $0.55 per lb of N and $4.50 per bushel of corn — that aren't exposed as inputs you can edit. Because commodity and fertilizer prices swing constantly, treat this one figure as illustrative only and recompute the return manually using your actual current prices rather than relying on the number shown.

Recovery Efficiency depends on the difference in total N uptake between the fertilized and unfertilized plots, and uptake is calculated from estimated total biomass, not just grain yield. Since biomass is derived by dividing yield by harvest index, an inaccurate harvest index scales your estimated stover tonnage — and therefore your estimated total N uptake — up or down, which shifts Recovery Efficiency even though the underlying yield data didn't change.