Field Trial: New Liquid Fertilizer Made With Biochar Doubled Pasture Yields

Liquid Biochar Fertilizer Beats Conventional Options on Yield and ROI, If the Formula Is Right

Farmers watching their fields produce less and less each year, despite dumping more and more fertilizer on them, may have a promising new option worth watching. Scientists tested several liquid biochar-based fertilizers in a real-world pasture trial, and the strongest performer was a nitrogen-enriched version that more than doubled pasture crop yields compared to conventional fertilizer alone. Importantly, that top formula also supplied substantially more nitrogen than the standard fertilizer treatment, so the result should not be read as a charcoal-only effect.

Standard fertilizers are notoriously wasteful. Up to 50% of applied nitrogen and as much as 80% of phosphorus never actually get absorbed by the plants they’re meant to feed. Instead, those nutrients wash away into waterways, polluting the environment and draining farm budgets. Biochar, a carbon-rich material created by burning organic matter at high temperatures in low-oxygen conditions, has shown promise in helping soil hold onto nutrients longer.

This study took a different approach: grinding biochar into ultra-fine particles and blending it with minerals and nutrients to create a liquid that can be sprayed directly onto fields. Four distinct versions were put to the test in a New South Wales pasture setting, and the differences between them turned out to matter enormously.

Not All Liquid Biochar Formulas Performed the Same

Researchers set up a field trial on a working pasture farm near Berrigan, New South Wales, an area with hot summers, cold winters, and an average annual rainfall of 438 millimeters. In May 2023, the team planted Italian ryegrass and three types of clover across 60 individual plots, each 5 meters by 5 meters.

Four different liquid biochar formulas were tested alongside fertilized and unfertilized control plots. Two were made from a wood-based material and liquefied using different methods. A third was made from wheat straw and poultry litter combined with various minerals, then enriched with additional phosphorus. The fourth used the same base but was further enriched with a commercially available liquid fish-based fertilizer, making it significantly richer in nitrogen. That formula delivered nitrogen at roughly four times the rate of the conventional farmer-practice treatment. Each formula was applied at 200 kilograms per hectare and tested both with and without additional conventional fertilizer.

Published in BioChar, researchers harvested the pasture grass twice and measured total yield, plant height, nutrient content, and soil chemistry. They also analyzed soil bacteria and fungi to see whether the new fertilizers were disrupting the microscopic ecosystem healthy soil depends on.

Nitrogen-Rich Formula More Than Doubled Crop Yields

When the harvest numbers came in, the nitrogen-rich formula was in a league of its own. It produced a total pasture yield of 42.20 tons per hectare. For context, the standard fertilizer treatment produced 18.75 tons per hectare, and plots that received no fertilizer at all produced just 11.53 tons. The other three biochar formulas landed in between, ranging from roughly 19 to 26 tons per hectare, a spread that underscores how dramatically results can differ depending on formulation.

Just as importantly, the nitrogen-rich formula did not appear to draw down the soil’s nitrogen and phosphorus reserves during the trial. When plants take up more nutrients than fertilizer supplies, they mine the soil’s existing reserves, a process that depletes soil health over time. Every other formula showed plants pulling nitrogen from the soil to compensate for what the fertilizer wasn’t providing. Only the nitrogen-rich formula kept both nitrogen and phosphorus balances positive.

Soil bacterial and fungal communities did not show measurable disruption at the point of measurement. That matters because heavy fertilizer use has long been associated with declining microbial diversity over time, and a product that boosts yield while leaving the soil’s living ecosystem intact would be a meaningful improvement over the status quo. Diversity remained comparable across all treatment groups at week 16, suggesting these formulas, applied at low rates, did not disturb that ecosystem during the trial. Because microbial analysis was only conducted at week 16, longer-term effects remain an open question.

Liquid Biochar Fertilizer Also Penciled Out Economically

Growing more is only half the equation for farmers, and the numbers have to work too. Every biochar formula in the trial returned more money than it cost to apply, with the nitrogen-rich version generating $2.54 for every dollar spent, compared to $2.18 for conventional fertilizer. Even the lowest-performing formula cleared $1.94 per dollar invested. Those figures are based on trial-specific pricing and will vary by location, crop, and market, but the margin suggests the approach is at least worth a serious look.

For farmers already spending more on fertilizer and seeing less in return, that is at least a reason to pay attention. One trial at one site in one season is not a prescription, but a liquid biochar fertilizer that more than doubled pasture yield without depleting the soil’s own nutrient reserves is the kind of early result that tends to prompt the next round of questions.

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Disclaimer: This article is based on a single field trial conducted over one growing season at one location in New South Wales, Australia. Results may not apply to other crops, soil types, climates, or farming systems. The economic figures cited are estimates based on trial-specific pricing assumptions and will vary in real-world conditions. This research has not been independently replicated at scale.

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