Study finds no change to soil from multi-species pasture

Research into soil health has thrown up some interesting results on straight ryegrass pastures compared with mixes.

Research into soil health has thrown up some interesting results on straight ryegrass pastures compared with mixes.

A study examining the benefits of multispecies pastures to ryegrass dominant pastures has found no difference between the two in soil carbon levels or soil biota.

The study covered a few years of multispecies pasture establishment, with the mix typically includes ryegrasses, clovers and herbs such as chicory, plantain, as well as other species such as turnips. It was run in rain-fed dairy pasture systems.

But, it also found multispecies pastures could provide more feed for livestock at the edges of the season, relative to ryegrass - although their success varied across farms and regions.

In comparison, ryegrass, although highly productive under the right conditions, tended to dry off if there was insufficient soil moisture.

The project, jointly funded through the Australian Government’s Future Drought Fund and Dairy Australia, examined successful multi-species pasture management in southern dairy systems, with the overarching aim of improving drought resilience.

University of Melbourne’s Professor of soil science Helen Suter is set to speak about what the science of this study, which finished late last year, shows at a three-day soil and pasture biodiversity event in Warrnambool next week.

The event will include several farm visits and farmers’ accounts of how they manage their pastures and soil health, run by Dairy Australia, with Meat and Livestock Australia backing.

Prof Suter said the study looked at productivity and drought resilience, as well as any additional soil health benefits of multi-species pastures compared to perennial ryegrass pastures.

There were 11 farms involved, spanning from North East Victoria, Gippsland and to the Western District, with researchers factoring differences in nutrient and grazing management, climate and soils across the sites.

“The focus of the project was to demonstrate climate resilient management approaches that can be up-scaled across the region,” Prof Suter said.

“They are very promising findings.”

While the ryegrasses provided high productivity in times such as spring, multi-species could add value at different times of the year.

“Multi-species can, however, be harder to manage; they all grow differently so grazing management can be challenging,” she said.

Ryegrass could deliver more even soil coverage, whereas some multi-species pastures may require re-sowing if areas bared out and pastures did not persist.

But multispecies pastures could provide greater ground coverage during dry periods.

Prof Suter said while there was no differences found in soil carbon, nitrogen or soil biota DNA between the ryegrass and multi-species pastures, that was “not surprising”.

This was because traditional dairy farms already had high fertility, carbon levels and high molecular activity.

“Any changes in carbon stock takes decades. All these things take time,” she said.

Longer term trials - Feed365 backed by Deakin will look at how three of the original 11 sites perform in terms of productivity, pasture compositional changes and soil properties.

MLA board director Jack Holden will also speak at the event on market drivers behind adopting practices that support soil diversity and health.

“Studies show that very few customers are willing to pay a premium for sustainability,” he said.

“However, incorporating sustainability into the overall package can help get our products into the hands of higher-value customers.

“We have an opportunity to stay ahead of customer expectations and define sustainability in ways that work for our farm businesses.”

Grounds for Growth is a three-day event in Warrnambool on March 4-6 and will include farm visits. For details, visit dairyaustralia.com.au