Wednesday, 09 January 2013

Mallee plantations exacted for yield loss in neighbouring fields

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mallee alleyAdjusting farming methods to account for the competition zone poses a cost to farmers and may be a significant factor in their decision to include mallee agroforestry in their system. Image: Courtesy FutureFarmCRCA NEW study looking at the effects of mallee agroforestry on traditional farming systems will give farmers better information about long-term land use changes.

The research titled ‘The extent and cost of mallee–crop competition in unharvested carbon sequestration and harvested mallee biomass agroforestry systems’ investigates the costs on production a mallee agroforestry system has on surrounding crops.

Department of Agriculture and Food Senior Researcher Doctor Robert Sudmeyer says the research shows mallee agroforestry can have significant impacts for farmers and they will need to consider these costs when deciding whether to implement mallee plantings.

The study was undertaken over the course of six years across 15 different wheatbelt farms looking at three common species of mallee.

It showed there is a significant reduction in crop yields in surrounding areas of the trees due to a ‘competition zone’ that comes into effect.

The competition zone is the area alongside tree plantings where crops struggle to get sufficient water and nutrients from the soil due to the surrounding trees.

On average the losses due to competition was equivalent to foregoing agricultural production for 14m on each side of unharvested belts and 9–10m on each side of harvested belts.

Mallee trees are planted on more than 12,000 ha of farmland across the South West of the state and this is due to increase under new renewable energy and cap-and-trade legislation.

Adjusting farming methods to account for the competition zone poses a cost to farmers and may be a significant factor in their decision to include mallee agroforestry in their system.

For mallee agroforestry systems to be a viable choice for farmers the costs to their production must be offset by the returns from the trees.

Dr Sudmeyer says while there may be viable biomass industries in the future it is hard to predict and hopes this research will show farmers the impacts this type of long-term land use change will have allowing them to make a more informed choice.

“When you start talking biofuels and things like that you are starting to get crystal-ball gazing because it is such a fast developing field,” he says.

“The whole point of the paper for farmers is to show the data for the competition.

“The farmer then has to think about ‘what does that mean to me’.”

The research was a collaboration between Department of Environment and Conservation and the Future Farm Industries CRC and the full paper can be found here.

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