Shift to sustainable rotation

Mallee farmers Gordon and Alistair Murdoch plan to start harvesting their canola within the week.MALLEE farmer Alistair Murdoch is always looking at new ways to ensure the sustainability of his family’s property at Kooloonong.
Nanjing Night Net

Farming in an area with an annual average rainfall of about 320 millimetres means retention of moisture is crucial as is maximising every dollar spent on inputs.

Alistair, his wife Simone and parents Gordon and Geraldine, crop 5000 hectares with wheat, barley, canola, chickpeas, lentils and lupins.

The cropping rotation has typically been a continuous cereal system but over the past two seasons, the family’s aim for a more sustainable rotation has led them to sow 60 per cent cereals and 40pc break crops.

“We’ve added lentils and chickpeas into the mix in the last couple of years,” Alistair said.

“More and more people in the northern Mallee are trying them but we’re only growing them on a very small scale, just for a bit of diversification.

“One of our biggest concerns is the cost of nitrogen, particularly with cereal-on-cereal rotations, and we’re trying to reduce that cost. Legumes may not be particularly profitable but they are great as a disease break and for N fixation.”

Alistair says using inter-row sowing into standing stubble gets the best out of the legumes.

“We have an issue in the northern Mallee with getting enough height in these crops before they start podding,” he said.

“By leaving high-standing stubble, it has a trellising effect, and the plants tend to grow up towards the sunlight.

“It allows the pods to be further off the ground which helps harvest efficiency as it allows a larger percentage of seeds to be harvested.”

Alistair has been using inter-row sowing since 2006 and says some of its other benefits include trash flow management, disease management and greater stubble retention to reduce evaporation.

Precision agriculture had played an important role in ensuring sustainability on the family farm.

“I started working with PA as an agronomist offering services in EM38 mapping and yield-mapping analysis,” he said.

This experience led Alistair to apply the same techniques to his own farm, and he began to create maps based on different soil types.

“From there, we started using variable rate application for seeding and top-dressing,” he said.

“It allows us to match inputs to production and boost areas of the paddock that will most likely give us the best economic return.

“In dry seasons, we’ve cut back our fertiliser rates on our heavier soils and put more on our lighter soils.”

Alistair said his family’s progress towards precision agriculture was gradual.

“Our first step was some yield mapping and from there, we went on to evaluating EM38 mapping, and it looked like a very good correlation on our farm,” he said.

“And then we had a shot at variable rate maps for seeding. Those maps have become a great resource in terms of cost control and matching return to input.”

The Murdochs sell a high percentage of their grain straight off the farm.

“We have strong links to the dairy industry which brings us some consistency,” he said.

“We also sell direct to export markets. We store grain on-farm and sell direct to multi-national companies, delivered to port rather than to local silos.

“It helps with logistics at harvest time and with the freight differential. It’s also about maintaining control and having more flexibility when executing the sale.”

There is upright ventilated storage on-farm but Alistair says grain bags give them flexibility with the amount that can be stored.

“We could store our whole harvest if we wanted to,” he said.

“Grain bags offer a good system for us because we don’t have to invest too much in fixed infrastructure. In good seasons we have the flexibility to store more on farm at a fairly minimal cost per tonne.”

Alistair plans to start harvest within the week.

“The season has been travelling pretty well but we did have two tight periods,” he said.

Alistair predicts an average to slightly above-average year for production.

“You learn lessons from every season and this year, it was the importance of summer weed control,” he said.

“This was one of our driest years during the growing season, with only decile 1 to 2.

“We’ve only had 120mm for the growing season. But the big difference this year was soil moisture and we wouldn’t have been able to take advantage of that without good summer weed control.”

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