NutrientChoice is an open-source decision-support tool that evaluates the economic feasibility of using separated dairy manure solids as a substitute for synthetic phosphorus (P) fertilizer under real-world conditions. It calculates net savings per acre, breakeven manure price, and breakeven hauling distance — three metrics that tell you whether manure makes economic sense for your specific situation. The tool integrates manure nutrient composition and moisture content, hauling logistics (distance, truck capacity, fuel, labor), synthetic fertilizer prices, co-nutrient credits (N, K₂O, S), and application costs into a single transparent comparison. Developed alongside peer-reviewed research, NutrientChoice translates complex economic relationships into actionable insights for dairy producers, crop farmers, extension agents, consultants, and policymakers.

• •Net Savings ($/acre): Is manure cheaper than synthetic P for your specific scenario?
• •Breakeven Manure Price ($/ton): What's the highest price you can pay and still break even?
• •Breakeven Hauling Distance (miles): How far can you haul manure before it becomes uneconomical?
• •"What would make manure viable?": If manure is not currently competitive, the tool tells you what input changes would flip the decision.

Where site-specific data are unavailable, the tool uses default values derived from global sensitivity and Monte Carlo analyses — not arbitrary assumptions. Transport cost parameters are fixed based on sub-model Sobol screening, nutrient composition ranges are drawn from published literature (Powell et al., 2010; USDA NRCS, 2010), and the drying cost adjustment equals $1.00/ton per % moisture reduction below 70%.

• •Open the Calculator tab and enter your data in sections A through E
• •Section A: Crop P₂O₅ requirement (lb/acre)
• •Section B: Manure moisture (%), nutrient content (% DM), application cost ($/ton)
• •Section C: Hauling distance, truck capacity, fuel, labor, and other logistics
• •Section D: Fertilizer prices (defaults provided for current market)
• •Section E: Optional soil carbon sequestration credit
• •Click "Calculate" — results appear on the right with plain-English explanations
• •Tip: Start with defaults to get a baseline estimate, then adjust inputs to reflect your operation

While developed for separated dairy solids, the framework applies to any solid organic nutrient source — for example, composted poultry litter, biosolids, or digested fiber. Simply enter the appropriate moisture content, P₂O₅/N/K₂O/S concentrations (% DM), and acquisition price. The tool will compute breakeven metrics on a consistent per-acre P₂O₅ basis.

Keshavarz Afshar, R. et al. (2026). "Economic Competitiveness of Separated Dairy Manure Solids as a Phosphorus Fertilizer Substitute." Pending publication.

This is a screening tool only — results are economic estimates, not guarantees of market success. It does not replace certified nutrient management plans. P-based application rate is calculated using total P₂O₅ content (not plant-available P), consistent with NRCS Standard 590. Single-year analysis only; multi-year soil P buildup is not considered. Prices are assumed constant within a season. Manure availability and storage constraints are not modeled.

We welcome feedback, bug reports, and suggestions for improvement! Contact: reza.afshar@dairy.org. Copyright © 2026 Reza Keshavarz Afshar / Dairy Management Inc. Released under the MIT License — free to use, modify, and distribute, even commercially.