Biofertilizer from manure lagoons is one of the most valuable resources a rural property can produce. When swine and cattle manure are managed correctly, they cease to be an environmental liability and begin to provide important nutrients for crops, contributing to reduced costs with mineral fertilizers and increased productive efficiency.
Pig and cattle manure, when properly managed, can be transformed into biofertilizer—a material rich in nitrogen, phosphorus, potassium, and organic matter, with the real capacity to replace or complement mineral fertilizers in crops. The result is a direct reduction in production costs and a more intelligent use of what the property already produces.
In this article, we explain what makes a waste lagoon a source of biofertilizer, what is needed to harness this potential, and the role of proper management in this process.
What is biofertilizer for waste lagoons?
Biofertilizer generated from manure lagoons is the liquid effluent resulting from the decomposition of organic matter—animal waste—in an aqueous environment. Over time, microorganisms present in the lagoon break down this organic matter and release nutrients in forms that can be assimilated by plants.
In practice, lagoon biofertilizer concentrates:
– Nitrogen (N): essential for the vegetative growth of crops. Present mainly in ammoniacal form, which is highly available to plants.
– Phosphorus (P): essential for root development and grain production.
– Potassium (K): important for product quality and plant resistance to stress.
Micronutrients: calcium, magnesium, zinc, copper, and other elements that complement crop nutrition.
Organic matter: improves the physical structure of the soil, increases water retention capacity, and stimulates microbial life.
The exact composition varies depending on the type of animal, its diet, the storage time in the pond, and, most importantly, the quality of its management. This is where a crucial factor comes in: the homogeneity of the material.
Why the quality of biofertilizer depends on lagoon management.
An improperly managed waste lagoon does not produce biofertilizer of uniform quality. At best, it produces inconsistent material—and at worst, a residue of low agronomic value that can even cause problems for the soil and crops.
The main enemy of quality is stratification. Without agitation, waste separates into layers:
– Surface crust: solid material accumulated on the surface, with a high concentration of some nutrients but difficult to utilize.
– Intermediate liquid layer: generally more diluted and with a lower concentration of nutrients.
– Bottom sediment: dense material with a high concentration of solids and nutrients, but which is inaccessible for pumping.
The practical result: when the farmer pumps the material from the lagoon to apply to the crop, he doesn't know exactly what he's applying. The concentration of nutrients can vary drastically depending on where the material was collected and when.
With proper agitation, the lagoon material becomes homogeneous—the same composition throughout the volume. This means that each application in the field delivers a consistent and predictable dose of nutrients, with real agronomic value.
Pig manure vs. cattle manure: differences that matter in the field.
Both swine and bovine manure have potential as biofertilizers, but they have distinct characteristics that affect their agronomic value and management methods.
In both cases, homogenizing the material before pumping is the step that determines whether the producer will apply a fertilizer of real value or a material of uncertain composition.
How to transform the lagoon into a consistent source of biofertilizer.
For a waste lagoon to consistently deliver high-quality biofertilizer, three elements need to be aligned:
1. Regular and efficient agitation
Agitation is the most critical step. It needs to be done before each pumping session—and ideally periodically to prevent excessive sedimentation and crust formation.
An agitator suited to the lagoon's profile—whether tractor-driven (Cardan or hydraulic) or fixed electric—ensures that the material is homogeneous at the time of pumping. Without this step, field application is compromised, regardless of the quality of the rest of the process.
2. Storage time control
The residence time of the waste in the lagoon directly affects the composition of the biofertilizer. Very short storage can result in material still decomposing, risking damage to crops. Excessive storage can reduce the nitrogen concentration through volatilization.
The ideal timing varies depending on the type of system, the volume of the pond, and the needs of the crops—and should be determined based on agronomic technical guidance.
3. Calibrated application in the field
Biofertilizer needs to be applied at the right dose, to the right crop, and at the right time. Periodic analysis of the lagoon material—which identifies the nutrient concentration—allows the producer to calibrate the doses and integrate biofertilizer into the farm's fertilization plan.
With these three elements aligned, the biofertilizer from the lagoon ceases to be an occasional supplement and becomes a planned and measurable part of the crop nutrition strategy.
The financial impact of making good use of the lagoon.
The cost of mineral fertilizers is one of the biggest pressures on the profitability of Brazilian rural properties. Producers who can replace part of this demand with their own biofertilizer have a real competitive advantage—especially during periods of high input prices.
Properly managed biofertilizer contributes to:
– Reducing the purchase of nitrogen, phosphate, and potassium mineral fertilizers.
– Improves soil organic matter in the medium and long term, reducing the need for soil amendments.
– Utilizing an input that is already being produced on the property, without additional raw material costs.
– Reducing the environmental liabilities of the lagoon, transforming it from a problem into a solution.
Investing in proper lagoon management — including the appropriate agitator — pays off in the form of savings on inputs and increased crop productivity. It's a win-win situation for most farms that already have a sufficient volume of manure.
The lagoon is already producing. Management determines its value.
The manure lagoon doesn't need to be treated as a problem to be solved. With proper management, it's a consistent source of biofertilizer—an input the property already produces, with real potential to reduce costs and improve crop nutrition.
The most important step in this process is ensuring the homogenization of the material before pumping. And that starts with the right agitator for your lagoon's profile.
The material is already there. How it's managed determines whether it becomes a cost or a result.
Want to make better use of the biofertilizer in your pond?
The first step is to ensure that the material is homogeneous before pumping. AGTO manufactures tractor-driven and electric agitators for swine and bovine manure lagoons — developed for the realities of Brazilian rural producers.
