Grains Research and Development

Date: 02.03.2015

Burnt stubble pre-empts frost risk

Author: Nicole Baxter

Image of farmer Gary Lang

Gary Lang burns wheat stubble before sowing canola to
reduce the risk of frost damage on his property north of Wickepin, Western Australia.

PHOTO: CBH Group

Although Western Australian grain grower Gary Lang says his property north of Wickepin has been relatively frost-free for the past two seasons, he sees frost as his number-one agronomic challenge.

Snapshot

Growers: Gary and Sue Lang
Location: Wickepin, Western Australia
Farm size: 4400 hectares (total); 4000ha (cropped)
Annual rainfall: 400mm
Soil types: light sands to clays
Soil pH (calcium chloride): 5.0 to 7.5
Enterprises: cropping, 2000 ewes
Typical crop rotation: canola/cereal/cereal; lupins/wheat/canola/cereal/cereal
Crops grown: wheat, barley, canola, lupins and oats
Seeding gear: 11.9-metre John Deere Conserva Pak with Simplicity airseeder set on 30-centimetre row spacings on 3m wheel centres

In the five years leading up to 2013, Gary estimates frost reduced wheat yields on his farm by 30 per cent, with the most severe damage recorded in 1998, 2005, 2008 and 2012.

But in 2011, Gary says he stumbled on a method of reducing the severity and duration of frost when preparing his paddocks for sowing.

“Our Conserva Pak airseeder isn’t the greatest machine for handling stubble and I was having issues with stubble becoming blocked, so I burnt a small patch of stubble on two different paddocks,” he says.

“When we came through at harvest we noticed there was an extra one tonne per hectare of wheat where the crop had been burnt.”

Since then, Gary has burnt his wheat stubbles immediately before sowing canola.

“The allelopathic effects of wheat stubble on canola are well documented and it is hard to get a small seed in a high stubble environment anyway, so we now burn our wheat stubbles because we’ve been frosted in canola as well,” he says.

Gary says a hot burn is done one or two days before canola is sown and there is not usually enough stubble in the following wheat crop to warrant burning.

In 2012, the GRDC-supported trials undertaken on Gary’s property by the Facey Group, the Department of Agriculture and Food, WA, and Living Farm showed removing stubble by burning decreased frost damage and produced a yield advantage in subsequent crops.

To beat the most damaging frosts, Gary does not start sowing wheat until after 20 May. Records show the most damaging frosts hit between 22 and 27 September.

“When we had really heavy stubble loads we were losing a lot of barley as well, nearly as much as wheat,” he says. “Barley is less susceptible to frost damage but not when the temperature is really cold.”

In future, he plans to sow more of his frost-prone country to oats because it tolerates cold temperatures better than wheat and barley.

Gary is a passionate supporter of research and for the past two seasons has hosted GRDC frost trials across 13 hectares of his farm. He plans to continue to collaborate with researchers going forward to help solve the problem of frost using a variety of approaches.

More information:

Gary Lang,
0427 881 034,

garyjlang@bigpond.com;

National Variety Trials,
www.nvtonline.com.au

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NVT through the lens of camera monitoring

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Trials deliver frost-susceptibility data

GRDC Project Code DAW00234, SDI00019

Region West