Catch crops head for high ground

A new project, with funding from the T R Ellett Agricultural Research Trust, has begun to research whether catch crops can be grown in particularly harsh winter conditions and what the benefit would be, not just to the environment but to the farmer’s back pocket too.

Pushing boundaries–Rakaia Gorge crop near to harvest

With only a few month’s worth of data and analysis so far, the yield results have been very pleasing for the research team.

And they are looking forward to repeating the experiments this winter and spring to validate year one performance, and give farmers confidence to consider planting catch crops in their own farm systems.

For many years researchers have been running experiments studying how catch crops can reduce environmental impacts on-farm.

This work has been important as winter grazing is a critical tool in many farm systems however there is a risk of contaminant loss to the environment and degradation of water quality.

The historical results have been largely positive with analysis showing up to 60% reduction in nitrate leaching in animal urine patches and approximately 40% decrease in sediment runoff.

Most of that research has been done on the lowlands in Southland, the West Coast and Canterbury.

A team, led by Dr Brendon Malcolm at Plant and Food Research, with AgResearch as a partner, started new experiments in August 2024 with four new sites in areas chosen for their more extreme climatic conditions.

These farms were sown with a mixture of species to understand whether the results on the lowlands could be replicated.

The site up the Rakaia Gorge is 400 metres above sea level and the one at Ashburton Lakes, 700 metres.

Two sites in Otago were also chosen in Middlemarch and Wanaka.

All farm sites were essentially treated the same, sown with different combinations of oats, ryecorn and Italian ryegrass.

However, the Middlemarch site was also planted with barley, and cultivation vs direct drilling treatments were tested at Ashburton Lakes.

Large strips of approximately 4 metres wide by 40 metres long were planted for the trials.

Brendon Malcom says initial observations have been promising.

Even in Wanaka where it was an exceptionally wet spring last year, the oat catch crops at the booting stage were harvesting at 4.5 tonnes DM to the hectare.

At the other extreme, the trial at Rakaia Gorge produced over 10 tonnes DM.

Important background information on all farms has been measured and recorded too, such as soil profiles both prior to sowing and later in the season once the crops were established.

Field days at each site occurred over late November 2024 to showcase early insights from the project to about 60 farmers and rural professionals.

“We wanted to keep the field days relatively small and intimate for the first viewing of the outcomes so that we could really dig deep into the discussions with the farmers and rural professionals,” Brendon Malcolm says.

“Once we have more data and analysis we want to share the results with more farmers so they can consider whether catch crops may work as part of their system, even in relatively harsh climatic conditions.”

He says without funding from the T R Ellett Agricultural Research Trust, this project would not have happened.

The research has really pushed the boundaries of what researchers thought was possible in terms of the kind of terrain and climatic conditions that would yield decent catch crops.

“We want it to be a win-win, for both the environment and the farmers and early results suggest that it can be.

“We are looking forward to doing another round of experimentation this year in winter/spring so that we can really ground-truth what we are saying to farmers who can then have the confidence to consider it for their own farm systems.”