Thursday, November 30, 2023

Canterbury Plains could lead the way in wheat production

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Growing our own could cut GHG and water consumption.
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By Delwyn Dickey for Our Land and Water

As Canterbury dairy farmers look to diversify land use, adding wheat production could make New Zealand self-sufficient in wheat while reducing greenhouse gas production and water demand.

The warm aroma of freshly baked bread is hard to beat. But surprisingly, even though we grow 452,000t of wheat in NZ, we import about 70% of the wheat we use to make our bread from Australia. 

“NZ was self-sufficient in milling wheat until 30 years ago,” Ivan Lawrie, general manager at the Foundation for Arable Research (FAR) said.

If NZ achieves self-sufficiency once again, this could help insulate the rural economy from the disruptions to global supply chains we have seen over the past few years, which have raised concerns around ongoing food security. 

A new agricultural model developed for the NZ arable farming sector looked at how to achieve this, with funding from the Our Land and Water National Science Challenge. Producing up to 700,000t of wheat is needed annually to cover current shortfalls and low production years, and meet dairy sector needs. 

The modelling showed, at current yields (9.9t/ha), an extra 25,000ha are needed to achieve self-sufficiency in milling wheat for human consumption – an extra 250,000t. Widespread use of precision agriculture to improve yields (to 12t/ha) could see this drop to an extra 20,000ha. 

From the environmental side, the modelling suggests that introducing this wheat production in a dairy system has clear positive impact, producing almost eight times less CO2-e biogenic emissions and using a third less water for irrigation than dairy.

The vast Canterbury Plains have some of the best arable soils in the country and produce most of the 425,000t of wheat grown annually in NZ. Along with plenty of growing expertise, this makes the region well set up for an increase in wheat cropping, Lawrie said.

Land could be freed up to accommodate extra wheat production as dairy farmers reduce stocking rates in response to freshwater and greenhouse gas regulations.

For dairy farmers wanting to grow wheat on some of their land there are several options. 

With their own machinery and tractor driver, they can do a reasonable amount of the work themselves. Alternatively, a contractor could come in to do the sowing, tillage and harvesting as required. 

“Leasing out the land to an arable farmer who would grow a crop and pay either a lease or a percentage of the crop to the owner of the property is another option,” Lawrie said.

There are specific requirements around storage and conditioning of grain, which would see a need for more facilities, an increase in capacity of some machinery and more transport, he said. 

More production could also help the numbers stack up for self-sufficiency.

“Domestic transport deficiencies and relative prices mean that sometimes it’s cheaper to bring wheat into the country than grow it in the south and bring it up to Auckland. Currently there’s not enough infrastructure and volume to make it happen,” advises Lawrie. 

With pockets of arable land further south in Southland and south Otago, this could provide the economy of scale. So too could production on pockets of arable land in the east and south of the North Island, Waikato and up to Northland, he said.

Few agricultural models anywhere in the world have been designed to combine production methods, emissions, energy, land use, water use, fertiliser use and profitability. Scientists at University of Canterbury and Manaaki Whenua Landcare Research developed a model specifically aimed at NZ’s agricultural systems and conditions, with data from NZ’s Arable Food Industry Council, StatsNZ, and the Food and Agriculture Organisation of the United Nations. 

Aimed at national and regional policy makers, and agricultural industry leaders, the model has used real world questions and scenarios, said modelling scientist Dr Clémence Vannier of Manaaki Whenua Landcare Research.

As well as looking at self-sufficiency for wheat, the researchers modelled two further scenarios for arable agriculture in NZ: one to mitigate greenhouse gas emissions, and another to grow for alternative protein production

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