Spring is the most important period of the year for pasture growth on many New Zealand farms. As soil temperatures rise and growth accelerates, demand for nitrogen and other nutrients increases rapidly.
But spring pasture performance isn't simply about how much fertiliser is applied. Root development, soil biological activity, nutrient cycling and the clover component of the sward all play a role in determining how effectively pasture converts available nutrients into feed.
This is where biological inputs can complement a conventional fertiliser programme.
What has EMNZ research shown?
Over a number of seasons, EMNZ has investigated biological pasture programmes under New Zealand farming conditions, looking beyond simply measuring short-term pasture growth.
Independent pasture work conducted by PastureFirst in Canterbury measured dry matter production, botanical composition and root development.
Across the trial, EMNZ biological treatments increased pasture production, with the programme producing up to 23% more dry matter than the untreated control.
But some of the most interesting responses were below ground and within the composition of the pasture itself.
More clover in the sward
Clover is a valuable component of productive New Zealand pasture systems because of its feed quality and ability to biologically fix atmospheric nitrogen.
In the PastureFirst trial, clover content was consistently higher in EMNZ-treated pasture.
In December, clover represented 69% of the control pasture compared with 88% following EM Soil & Crop and 82% following Plant-Stim.
By April, clover levels had declined seasonally across all treatments, but the same pattern remained: 39% in the control compared with 52% for EM Soil & Crop and 47% for Plant-Stim.
This is particularly interesting as farmers look for ways to maintain productive pasture while improving nitrogen efficiency.
Building a bigger root system
What happens above ground is only part of the pasture story.
Plant-Stim also produced a substantial response in root development. Root mass increased from 149 g in the control to 211 g with Plant-Stim in the trial.
A larger, more active root system gives the plant greater capacity to explore the soil for water and nutrients and can help support resilience through periods of environmental stress.
This is one of the reasons we see Plant-Stim as more than simply another foliar input. It is designed to stimulate plant and root activity at times when the crop or pasture has the greatest opportunity to respond.
Can biology help us use nitrogen more efficiently?
This is becoming an increasingly important focus of EMNZ's research.
Our objective isn't to suggest that biological products simply replace nitrogen. Nitrogen remains an important driver of pasture production.
The more interesting question is whether we can create a more biologically active pasture system that makes better use of the nitrogen and nutrients already being applied.
Previous pasture work has given us encouraging indications, and during the 2026/27 season EMNZ is taking this further with on-farm dairy programmes examining biological inputs alongside reduced nitrogen strategies.
These programmes include combinations of Plant-Stim, EM Balance and Amino, with different nitrogen rates being compared under commercial grazing conditions.
The aim is straightforward: can we maintain pasture production while improving the efficiency of the overall fertiliser programme?
We'll be sharing the results as the season progresses.
Where does Plant-Stim fit this spring?
For established pasture, Plant-Stim provides a simple way to introduce biological stimulation into an existing spring programme.
Plant-Stim is a fermented plant extract produced using EM technology and contains naturally derived compounds from lucerne, kelp and willow alongside beneficial fermentation metabolites.
Applied at 5 L/ha, it can be incorporated into existing pasture spray programmes, making it relatively easy to introduce without changing the farm's underlying fertiliser strategy.
For farmers wanting a broader biological programme, Plant-Stim can also be combined with EM Balance and other EMNZ inputs depending on the objectives of the farm.
A different way of looking at spring growth
Spring will always be about growing feed.
But increasingly, the question isn't simply “How much fertiliser can we apply?”
It's also:
How efficiently can the pasture use it?
By supporting roots, soil biology, nutrient cycling and the clover component of the pasture, biological inputs provide another tool for farmers looking to build productive and increasingly efficient pasture systems.
And that's exactly what EMNZ's pasture research programme will continue investigating.
