You’ve probably heard agronomists and regenerative growers say they can reduce fertilizer without losing yield. It sounds great—more for less. But the natural follow-up question is fair: how long can that last? Aren’t they just mining the soil?
Short answer: no—at least not in a properly managed regenerative system.
Let’s break down why.
At its core, yield has always been a function of a plant’s ability to access nutrients and water. Early farmers understood quickly that what a crop removed needed to be replaced to maintain production. That’s why fertilizer recommendations still consider crop history, yield, and residue management.
But this traditional view treats soil like a fuel tank—you put nutrients in, the crop takes them out, and you refill.
In reality, soil functions more like an engine.
The crop is the output. Fertilizer is part of the fuel. But the soil system is the engine that determines how efficiently that fuel is used. Its physical structure (texture, aggregation, porosity), chemical balance (pH, nutrient ratios, salinity), and biological activity (microbes, fungi, protozoa) all work together as interconnected components that control how nutrients are stored, transformed, and delivered to the plant.
If the engine is weak, you burn more fuel to get the same result.
If the engine is strong, every pound of fertilizer goes further.
Mining only occurs when nutrients leave the system faster than they are replaced or replenished through natural cycling. A regenerative system focuses on strengthening that engine so nutrients are released, recycled, and retained more efficiently over time.
Why biology matters so much
Biology is what drives nutrient cycling.
Without beneficial bacteria, fungi, and other soil organisms, much of the nutrient pool—whether from crop residue, manure, soil organic matter, or even applied synthetic fertilizer—remains in forms that are not readily available to plants.
These microbes are responsible for converting both natural and synthetic nutrient sources into plant-available forms through natural biological processes in the soil, including mineralization, nitrification, and immobilization–release cycles that regulate nutrient timing.
While microbes are actively transforming nutrients, they are also producing compounds that help bind soil particles into aggregates, improving structure, reducing compaction, and increasing pore space for air and water movement.
This biological component directly drives fertilizer efficiency.
A healthy soil system cycles nutrients more effectively, synchronizes supply with crop demand, and reduces losses.
A degraded system relies more heavily on applied fertilizer because less of the existing nutrient pool is being accessed.
Prairie soils prove the point
Much of Western Canada is built on Chernozemic soils—formed over thousands of years under deep-rooted grassland ecosystems.
These systems produced significant biomass without synthetic fertilizer, not because nutrients were unlimited, but because the system continuously cycled them. Deep roots, constant residue return, and active biology created a highly efficient nutrient loop.
Modern agriculture disrupted parts of that cycle. Tillage reduced organic matter. Simplified rotations limited biological diversity. Periods of bare soil increased nutrient losses. Fertilizer became essential to maintain yield—but also masked declining system efficiency.
How much potential is sitting in your soil?
A typical prairie soil weighs roughly 2 million pounds per acre in the top six inches. That often equates to around 2,000 lb/ac of total nitrogen.
However, only a small fraction—typically in the range of 1–3% per year—is mineralized into plant-available forms, depending on moisture, temperature, organic matter, and biological activity.
The key question is not how much nitrogen exists in total, but how efficiently your soil can cycle and supply it during the growing season.
Regeneration is about efficiency—not elimination
A regenerative approach focuses on improving that supply system by:
- Reducing disturbance to protect structure and organic matter
- Maintaining living roots to feed biology
- Keeping residue cover to reduce nutrient loss
- Supporting balanced chemistry to enable nutrient availability
Even in a regenerative system, crop removal still needs to be accounted for over time. The goal is not to ignore fertilizer, but to reduce reliance on it by improving how efficiently nutrients are cycled, retained, and used.
Fertilizer reductions are not automatic or universal. They depend on soil type, organic matter levels, biological function, weather conditions, and management. The objective is to match inputs more precisely to what the soil can supply—not to remove them blindly.
The difference between mining and regeneration
Mining happens when nutrient removal exceeds both fertilizer inputs and the soil’s ability to replenish nutrients through biological cycling and organic matter turnover.
Regeneration increases that replenishment capacity.
As the system improves, more of the crop’s needs are supplied by the soil itself, and less must come from applied inputs—without sacrificing productivity when managed correctly.
Fix the engine, and your soil delivers more!
