High-Yield Wheat Crop

May 2010

Growing a high yielding wheat cultivar, "Wakanui"

Craige and Roz Mackenzie attempted to win a place in the Guinness Book of Records for the world record for the heaviest wheat crop per ha. They narrowly missed the record, but still serve as good example of how to produce a high yielding crop. Craige has been described as a very good advocate for arable farming.

The Mackenzies got really close to a world record last time they tried two years ago, but the crop had a dryland corner on a stony ridge. Craige says its all about growing a consistently even crop across the whole field.

In the meantime Mike Solari, a farmer at Otama just outside Gore won the record in 2007 with a harvest of Savannah feed wheat which cropped at 15.36t/ha from 14.68ha. He is the current holder of the record.

Feed wheat is the heaviest yielding wheat, and doesnt have the worry about the same quality parameters that you would have with milling wheat: so you can concentrate more easily on maximizing yields. You dont run the same risks with feed wheat, and so while the prices are not as high for feed wheat, it yields well if planted early.

Craige has been described as a very good advocate for arable farming.

Ross has been working for Plant and Food (and its predecessors) for 39 years as a research agronomist, and he says the system to produce new cultivars of cereals is like a continuous pipeline of potential material.

We work on replacing cultivars every three to four years with a new improved variety which has either lower production cosst, higher yield or better quality whatever is going to benefit the growers or end users in the industry. It could be better disease resistance or better straw strength, but yield is the final outcome of the research.

Feed wheats are used in dairy, chicken and pig feed within NZ.

This is the first year the Mackenzies have grown Wakanui wheat. Craige says theres not a lot between some of the varieties, and differences often depend on location and time of sowing. Feed wheat needs a very long season, and also benefits from irrigation. Irrigation is an advantage for long season crops.

While to get a really good crop its best if the previous crop in the paddock was peas, this paddock, which Craige says is the best and most even paddock on their farm, grew carrots last year. A break crop such as clover, peas or beans is best before a wheat crop to reach a maximum yield.

Wakanui is a wheat which originated from lines introduced by Sejet Plant Breeding in Denmark to Plant and Food Research at Lincoln: they have a long-standing collaboration to evaluate and commercialise cereals.

The cultivar was selected and developed for NZ conditions by Plant and Food Researchs collaborative Feed Grains Development Programme, with Canterbury Seed and Luisetti Seeds.

Plant and Food agronomist Ross Hanson says Wakanui, released three years ago, has consistently topped the tables in yield, both in trials and now commercially.

He says its secret to success is a long slow grain filling time, and a large grain size. Because this season has been cool, and is about two weeks behind the usual time of harvest, its had another two weeks to fill the grains more, so yields in general will also be pretty good.

Within a head of wheat there are spikelets, and a lot of feed grains only have four grains across each spikelet. In good conditions Wakanui will produce five grains, and Craiges crop is growing some of these.

Wakanui is a little bit taller and produces a little bit more straw so a few more nutrients could be channeling into the grain. Yield and feeding are directly related, so the plant has to have enough nitrogen for those extra two weeks of growth too. Demand for nutrients is greater in a higher yielding crop.

Anywhere there has been adequate soil moisture the yields will be pretty good. Even on dryland situations without irrigation Wakanui performs well, Ross says.

Craige Mackenzie is confident about Wakanui, and says because it is robust in nature it means farmers use less chemicals on it.

This 9ha crop was sown on 15 April, which is reasonably early, Craige says. To be eligible for a world record, the crop needs to be more than 8ha in size.

He has irrigated it four times, the first time in November, then consistently through the summer. He uses overhead guns to irrigate this particular field.

And he uses a neutron probe to monitor soil moisture levels to make sure the plants arent getting stressed by lack of water.

While their rainfall averages around 900mm, this past year it was a bit less than 800mm. October was very wet and November and December were reasonably dry, he says.

How do you grow a big crop?

The first thing to do, which seems counter-intuitive, is to start with a very low seeding rate of 50kg/ha, which is about half that of standard application rates. A good fungicide and insecticide programme is also a very important part of the overall strategy.

You have to have the confidence to do everything else right. This low seeding rate gives you very strong plants which can intercept a lot of light. And it halves seed costs.

And you dont need to use any plant growth regulator. Wakanui is a very robust wheat. It came up well in FAR trials. These FAR cultivar trials are very helpful.

We do plant counts, test the soils for nitrogen levels, and from there we know how many kg it takes to grow one tonne of wheat. We make sure we get the appropriate amount of nitrogen on.

Growing a heavy crop is a whole package, and we hope we can get to at 16tonne crop. Craige harvests the crop himself, with a normal combine. Theres nothing special. But its been a team effort to get to this stage he says, and its about everybody, not just him.

This crop hasnt been sold yet. While most of the other crops are contracted, this one isnt yet.

To get all set up for a world record entails jumping through a few hoops Craige says. You need Justices of the Peace to be present, and a certified weigh bridge. The paddock has to be surveyed also. This time they are bringing in a set of portable scales so the trucks can be weighed in the yard instead of being sent off to the nearest weigh bridge. Photos also have to be sent off.

And once the crop has been harvested it takes a bit of time for the Guinness Book of Records people to verify the bid.

Craige says the world record attempt was about highlighting Canterburys world class arable industry and proving the teams agronomic skills.

The farm is 200ha of mixed cropping, with wheat and ryegrass seed making up two-thirds of the operation. A range of vegetable crops are grown: hybrid carrots, hybrid radishes, hybrid pak choi, broad beans for seed, faba beans, marrowfat peas, oats, and in the past they have grown hemp.

And they have nine sheep. Right next door they have a 220ha diary farm with 800 cows.

Craige has been home farming here since 1981, and its been 16 or 17 years since he and Roz took it over.