Farming has always been measured in numbers. Kilograms of fertiliser per hectare, tonnes of dry matter grown, litres in the vat or kilos on the hook. But one factor that often gets overlooked is how well the soil is functioning, shown by earthworms, soil structure and pasture resilience. That function is driven largely by soil biology and determines how much of the fertiliser we apply the plant can actually use.
Fertilizer New Zealand research has consistently shown that soils with strong populations of beneficial microbes are much more efficient at turning applied nutrients into plant growth. Nitrogen, phosphorus and potassium may all be present in the soil, but without active biological processes, a good portion of those nutrients stay locked up and unavailable to pasture or crops.
Biological fertilisers work by supporting or reintroducing naturally occurring soil microbes. These include organisms such as Bacillus, Trichoderma and Azotobacter. Some help fix nitrogen from the air, others release phosphorus tied up in the soil, and some support root health. Biologicals don’t replace conventional fertiliser. They make the nutrients you’re already applying work harder, reducing waste and improving return on spend.
This isn’t theory. Fertilizer New Zealand field trials in Canterbury, along with farmer observations from Waikato, Southland, the West Coast and other regions, have shown that integrating biological fertilisers into existing fertiliser programmes can maintain, and in some cases lift, pasture production while reducing synthetic fertiliser use by around 10 to 20 percent. With fertiliser prices where they are, those gains matter.
When soil biology is functioning well, plants develop stronger root systems, access nutrients more consistently and recover faster after grazing. Improved nutrient uptake also means fewer losses through leaching and runoff, which benefits both the farm budget and the environment.
Application matters. Some biological products are sensitive to timing, temperature or chemical compatibility. Fertilizer New Zealand has found that products such as VITALIFE can be applied almost year-round because the microbes are delivered with a food source and protection, giving them a better chance of surviving and establishing in the soil.
Another key advantage is resilience. Farms with healthy soil biology tend to bounce back faster after stress events such as drought, flooding or heavy grazing. Microbes support nutrient uptake and root function during tough periods. This resilience doesn’t always show up immediately in farm accounts, but it becomes obvious when seasons turn challenging.
There is no silver bullet in farming, and biological fertilisers are no exception. They work best as part of an integrated nutrient strategy that includes regular soil testing, good grazing management and sensible use of conventional fertiliser. Used correctly, they offer a practical way to improve nutrient efficiency without compromising production.
At its core, this is about farming smarter, not harder. Supporting soil biology helps farmers get more value from every kilogram of fertiliser applied. It reduces waste, lowers risk and builds long-term soil health.
Investing in soil biology isn’t about chasing trends. It’s about using proven science to future-proof farming systems. Healthy soils grow better pasture, handle stress better and support sustainable production. That’s a return worth backing.
Biological Fertiliser - Smarter not More