Wednesday, April 24, 2024

Clover trial aims to boost hill country pasture

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Hope is for big gains in feed quality, finances and stability of vulnerable soils.
The hope is that strategic grazing could see the clover produce more of its own seed and seedlings for the following autumn. Photo: Wikimedia Commons
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By Delwyn Dickey for Our Land and Water

Giving clover a helping hand to establish long term on hill country farms could lead to big gains in feed quality and finances, while helping to stabilise vulnerable soils. 

The lotus varieties of clover – which can reduce methane and nitrous oxide emissions when consumed by ruminant stock – could also improve farm environmental performance. 

Slower-growing clovers struggle to thrive when competing with the faster-growing pasture grasses on hill country. 

For decades farmers have been oversowing on the hills to increase the amount of clover in pasture long term, but with limited success. Hill country terrain, often unsuitable for farm machinery, makes pasture management harder than on the more productive lowlands, where cultivation, fertilising and reseeding are much easier. 

Limited machinery use often sees supplementary feeds like silage, maize and summer crops also out of reach for hill farmers. Deferred grazing is one of the few options open for growing a supplementary crop, but is still not widely used.

With around 6 million hectares of hill farming country in New Zealand unable to be cultivated, improving the quality of the pasture by increasing clover content could have widescale benefits.

Now, a group of researchers led by forage systems specialist Blake Gunn of Agricom, with funding through the Our Land and Waters Rural Professionals Fund, are looking to see if changing the timing of deferred grazing management will allow clover to establish better. 

AgResearch scientist Katherine Tozer says the trial is ‘looking at a mosaic of grazing practices to fit in with different farms’ and farm goals.

and keep it growing strongly enough to hold its own during the rest of the year.

The research is being carried out on the sheep operation side of third-generation Coster family-owned Mataiwhetu Station, on the lower Kaimai Ranges in the Bay of Plenty. Standard deferred grazing is being looked at alongside spring grazing to suppress grass growth, and summer spelling.

“There is a strong correlation between legume [clover] content and production in pastures. When looking at alternative ways to increase productivity on hill farms, this makes increasing legume content low-hanging fruit,” Gunn said.

Deferred grazing generally sees paddocks locked up between mid-spring and late summer, so stock will have feed at a time when other pasture may be struggling in the warmer, drier conditions. 

Tweaking the practice for hill country conditions to encourage more clover could lead to an increase in dry matter, increase fertility by fixing more nitrogen in the soil, and support erosion control due to more robust pasture root systems binding soil together. 

It’s not just clover that benefits from deferred grazing. Recent research has shown spelling the paddocks this way also gives ryegrass species time to build up water-soluble carbohydrate energy reserves, important for long-term plant health. 

AgResearch scientist Katherine Tozer is keen to emphasise that the single-farm trial is just the first step, with more research needed. 

“We’re looking at a mosaic of grazing practices to fit in with different farms, with what the farmers are wanting to achieve.”

When the trial wraps up later this year, it will have measured pasture outcomes like dry matter, feed energy and plant density. Stocking rates and the size and weights of lambs and ewes grazing the land will also be measured. 

The research team will use Farmax to gauge production, profit and environmental considerations, including having lotus clovers in the mix. 

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