What is biofertilizer — with examples?

A biofertilizer is any substance that contains living microorganisms — or the metabolic byproducts of those organisms — that, when applied to soil or crops, improves nutrient availability and supports plant growth. The key difference from a synthetic fertilizer is that biofertilizers work with the biological processes already in your soil, not around them.

They don’t dump nutrients into the root zone. They activate and multiply the organisms that make nutrients bioavailable — the ones that were already there but suppressed by years of chemical input use.

Feito na Roça field operation — where the protocol was developed and tested.

Common examples:

• Rhizobium — fixes atmospheric nitrogen in legume root nodules
• Azospirillum — nitrogen-fixing bacteria for grasses and cereals
• Mycorrhizal fungi — extends root surface area, dramatically improving phosphorus uptake
• Azotobacter — free-living nitrogen fixer for non-legume crops
• Liquid biofertilizer (bokashi-based) — fermented organic matter, what I produce and use on my own operation
• Vermicompost leachate — worm castings liquid, loaded with beneficial bacteria and growth hormones

Which is the best biofertilizer?

There is no universal answer — and anyone who gives you one is selling something. The best biofertilizer depends on three things: your crop, your soil type, and your application method. That said, here’s how I think about it in practice:

For small producers running mixed operations — which is most of us — a well-made liquid biofertilizer (fermented organic base) is the most practical choice. It’s inexpensive, versatile across crops, and can be produced on-farm in 25–30 days.

What are the three main sources of biofertilizers?

Biofertilizers come from three biological origins. Each has a different mechanism of action in the soil:

• Bacteria — the largest group. Nitrogen-fixers (Rhizobium, Azotobacter, Azospirillum) and phosphate-solubilizers (Bacillus, Pseudomonas). These are the workhorses of soil fertility.
• Fungi — primarily mycorrhizal species that form symbiotic relationships with roots. They extend root reach by up to 700% and are critical for phosphorus uptake in low-input systems.
• Algae (Cyanobacteria) — particularly useful in rice paddies and flooded systems. Species like Anabaena fix substantial amounts of nitrogen and contribute organic matter as they die off.

Fermentation stage — the biology in action.

Field application — same protocol, different crop stages.

What are 5 types of fertilizers?

• Synthetic/Chemical fertilizers — fast-acting, high NPK, but depletes soil biology over time and creates input dependency
• Organic fertilizers — compost, manure, bone meal. Slow release, improves soil structure, no harmful residue
• Biofertilizers — microorganism-based. Improves nutrient availability without adding synthetic chemistry
• Mineral fertilizers — rock phosphate, greensand, gypsum. Naturally mined, slow-release mineral nutrients
• Liquid fertilizers — can be synthetic or biologically derived. Applied via fertigation or foliar spray for fast uptake

Which materials can be used as biofertilizers?

More than most producers realize. The barrier to entry is lower than the industry wants you to think:

• Animal manure (cattle, poultry, swine) — fermented, not raw
• Plant-based organic matter — crop residues, green biomass, banana leaves, sugarcane bagasse
• Kitchen and farm waste — vegetable scraps, fruit pulp, whey
• Wood ash — adds potassium and adjusts pH in acidic soils
• Molasses — energy source for microbial multiplication during fermentation
• Effective microorganism (EM) cultures — accelerates fermentation, widely available
• Vermicompost and worm leachate — among the most microbiologically active inputs available

Most of these materials are either free or close to it on a working farm. The protocol — how you combine, ferment, and calibrate them — is where the knowledge lives.

What are three types of fertilizers?

When producers talk practically about fertilizer categories, the three that matter most are:

• Nitrogen fertilizers — drive vegetative growth. Biofertilizer equivalents: Rhizobium, Azospirillum, Azotobacter.
• Phosphorus fertilizers — critical for root development and flowering. Biofertilizer equivalent: mycorrhizal fungi, phosphate-solubilizing bacteria.
• Potassium fertilizers — governs water regulation, disease resistance, and fruit quality. Biofertilizer equivalent: potassium-solubilizing bacteria (Bacillus mucilaginosus), combined with wood ash application.

How do I apply biofertilizers correctly?

Application method depends on what you’re using. Here’s the practical breakdown:

Application protocol — fertigation, foliar, and soil drench compared.

• Fertigation (drip or sprinkler irrigation) — most efficient for liquid biofertilizer. Dilute 1:20 to 1:50 depending on concentration. Apply in the morning or late afternoon, never midday heat.
• Foliar spray — apply directly to leaves. Best for fast uptake during early growth stages. Dilute more aggressively (1:100) and filter well to avoid clogging nozzles.
• Soil drench — pour directly at the base of plants or into furrows at planting. Best for mycorrhizal inoculants and slower-release products.
• Seed coating — for Rhizobium and similar inoculants. Coat seeds just before planting. Keep out of direct sunlight and do not mix with synthetic fungicide-treated seeds.

What are two bacterial examples of biofertilizer?

• Rhizobium — forms nodules on legume roots (soybeans, beans, clover, peanuts) and converts atmospheric nitrogen into a form the plant absorbs. Can supply 50–200 kg of nitrogen per hectare per season — eliminating the need for synthetic N in legume rotations.
• Azospirillum brasilense — colonizes the root zone of grasses, cereals, and sugarcane. In addition to nitrogen fixation, it produces growth hormones (auxins, gibberellins) that stimulate root development and drought tolerance. Field trials consistently show 10–30% yield improvement in corn and wheat.

Are there any risks to using biofertilizers?

Honest answer: yes, but they are manageable and far fewer than the risks of heavy synthetic input use. Here’s what’s real:

• Inconsistent results — biofertilizers are living organisms. Temperature, soil pH, and moisture affect their survival. A product that works in Florida may underperform in Arizona without adjustment.
• Short shelf life — most liquid biofertilizers lose potency within 6–12 months if stored incorrectly. Keep refrigerated, out of direct light, and away from heat.
• Incompatibility with chemical inputs — applying biofertilizer alongside certain pesticides or herbicides kills the inoculant. This is the most common failure point for producers transitioning from conventional systems.
• Slower visible response — synthetic fertilizers show green-up in days. Biofertilizer results build over weeks and accumulate across seasons. It’s a different timeline — not a failure signal.

The risks I don’t see: environmental toxicity, soil acidification from overuse, or health risk to the producer or end consumer. On those metrics, biofertilizer is unambiguously safer than synthetic alternatives.

What crops benefit most from biofertilizers?

Crop response data from Solo Vivo field trials — AGERP partnership.

• Legumes (soybeans, beans, peanuts) — Rhizobium inoculants reduce or eliminate synthetic nitrogen needs entirely
• Cassava / Yuca — mycorrhizal fungi dramatically improve phosphorus uptake in the low-input, sandy soils where cassava is typically grown
• Sugarcane — Azospirillum and diazotrophic bacteria reduce N requirements by 30–50% in established fields
• Corn and wheat — Azospirillum shows consistent yield response in field trials across multiple climates
• Vegetables (tomato, pepper, leafy greens) — high responsiveness to foliar-applied liquid biofertilizer, especially during transplant and flowering stages
• Fruit trees — mycorrhizal colonization improves drought tolerance and fruit quality over time; long-term investment that pays out across seasons

What are the disadvantages of biofertilizers?

I’d rather you hear these from me than discover them mid-season:

• Longer time to visible results — if your cash flow depends on a fast-responding crop this season, you need to plan the transition carefully
• Requires soil baseline knowledge — using biofertilizer without knowing your soil pH, organic matter, and existing biology is like prescribing medicine without a diagnosis
• Not a complete replacement (yet) — in severely depleted soils, you may need 1–2 seasons of combined organic + biofertilizer inputs before you can fully reduce synthetic use
• Quality varies widely by product — the commercial biofertilizer market has inconsistent labeling. CFU counts (colony-forming units) matter — low-quality products may have no viable organisms left at point of use

Are biofertilizers expensive?

Commercial biofertilizer products range from $15 to $80 per application depending on crop area and formulation. Compared to synthetic fertilizer programs running $150–$400+ per acre per season, they are significantly cheaper — especially over time.

But the real cost comparison happens when you produce your own. On my operation, a 200-liter batch of liquid biofertilizer — enough for approximately 2 hectares of fertigation — costs under $12 in materials. Production time: about 4 hours spread over 30 days of fermentation.

The math is straightforward: if you’re spending $300/acre on synthetic inputs and biofertilizer reduces that by 40–60%, you recover the system cost in the first season — often in the first application.

Can I make my own biofertilizer?

Yes. And on a small or medium operation, I think you should — for two reasons. First, cost. Second, control. When you make it yourself, you know exactly what’s in it, you can adjust the formula to your soil, and you’re not dependent on supplier availability or shipping timelines.

The materials you need are almost certainly already on your farm: animal manure, plant matter, molasses, water, and a sealed fermentation container. The protocol — ratios, fermentation temperature, pH monitoring, when to stop fermentation, how to dilute for different application methods — is what takes knowledge to get right.

On-farm production at Feito na Roça — materials are simple; the protocol is what determines results.

I’ve documented the complete protocol — including the failed batch that taught me what not to do — in the Solo Vivo course. It’s the same system validated through our AGERP field study, adapted for small and medium operations in tropical and subtropical climates.