Environmental needs vital in agriculture

24 Mar, 2004 10:00 PM

THE importance of environmental management to the future of sustainable agriculture underpinned each of the presentations given by Nuffield scholars last week.

They were summarising what they'd learnt from their Nuffield scholarships, awarded to them in 2002.

Brendan Smart from Keith in NSW, a former Nuffield scholar, summed up the role farmers have to play in environmental management at the conclusion of the presentations when he said that while farmers didn't profess to be environmental activists, they did profess to be active environmentalists.

Benjamin West from West Wyalong in New South Wales gave his presentation on continuous cropping (minimum to no-till opertaions) in marginal rainfall areas to establish the techniques necessary to maintain a sustainable farming system.

Queensland scholar Brendan Kersh talked on sustainable production/grazing management on arid rangeland pastures, and living with regulation as well as shouldering the cost of delivering social benefits.

Lastly, Richard Heath from Curlewis in New South Wales, delivered his presentation on the smarter application of fertiliser for crops and nitrogen management and the different methods of fertiliser use in general, to develop an overall picture of best practice in nutrient delivery.

p Richard Heath

EACH year about 50 million tonnes of fertiliser nitrogen is applied to cereal crops around the world, and only 33pc of this nitrogen is recovered in the harvested grain.

A startling figure that was the impetus behind Richard's study topic centred upon the investigation of of the approach to nitrogen management, with a particular focus on canopy management through split applications of nitrogen in the USA, the UK and Australia.

"In 2001 an agronomy program that our farm was involved in (Opti-Crop operated by Purehouse Rural Agribusiness services) conducted some split nitrogen trials on wheat that revealed similar if not greater yields could be obtained from smaller amounts of post-applied nitrogen compared to the standard levels of pre-applied fertiliser," he said.

"The agronomy theories used in those trials were a challenge to conventional wisdom on the Liverpool Plains and inspired me to find out just how much more efficient we could become with nitrogen fertiliser."

In particular, the focus of the study tour was assessing the different approaches to nitrogen management in a range of cropping environments while remaining focused on cereals.

In addition, a range of crop sensing products were looked at that were developed to try and provide in season determination of nitrogen requirement, and whether or not the technology was having an influence on the ability to improve nitrogen use efficiency.

These included the Hydro N Sensor and Sygenta Farmstar, which both provided recommendations for varying an average rate of topdressed fertiliser within a field.

In addition the N-Tech Greenseeker, a product capable of providing an absolute determination on rate based on the condition of the crop and expected response to fertiliser, was also studied.

"Precision farming guidelines for nutrient application have been developed in the UK, which use remote sensing to monitor crop growth and make nitrogen recommendations enabling an understanding of how manipulation of crop structure through nitrogen applications can produce the most efficient yield producing canopy," Richard said.

According to Richard, many farmers situated in the predominantly winter dominant rainfall areas of Australia are now approaching nitrogen application from a canopy management perspective.

"I believe there is potential for improvement in nitrogen use efficiency in areas where split applications of nitrogen have not been common practice such as the northern cropping zones,"he said.

"There is a need for a better understanding of how the most efficient crop growth in terms of water use can be achieved through nitrogen manaegment before precision application techniques for nitrogen will be fully adopted."

p Benjamin West

NO-TILL farming now encompasses an area of 70 million hectares worldwide with the largest expansion in no-till practices being seen in Argentina, Brazil and Australia, according to Nuffield scholar Ben West.

Ben and his family have been no-till farming for seven years near West Wyalong in central New South Wales, and Ben's aim was to scale up the no-till program on the property, an objective that was further consolidated by the Nuffield study tour.

"The biggest challenge Australian producers face is increasing productivity while maintaining the health of the soils," he said.

"We face an ever-increasing demand for cereals worldwide, while at the same time as producers we must be conscious of increasing land use efficiency, improving crop turnaround times and lowering our production costs," he said.

"There is a far greater emphasis in South American countries on increasing organic matter, with levels of around 4-6pc quite common as opposed to our levels of less than 1pc in Australia.

"Cover crops are also widely used, and disc style seeding along with direct seeding of crops into cover crops largely in the higher rainfall areas of Latin America.

"On my return home to our farm I now view trash as residue and now search for creative ways to get through residues, I can also see the benefits retaining stubble which is the closest we can get to cover cropping in dryland areas of Australia.

"In Australia the one thing we are lacking is rainfall and by no-till farming we can increase productivity in farming areas and can best utilise less suitable land."

p Brendan Kersh

THE focus of Brendan's presentation centred upon sustainable production and grazing management practices of arid rangelands mainly within South Africa, and the way in which these practices applied within the context of his own Queensland beef enterprise in the northern rangelands.

Humorous anecdotes relating to his travels were numerous, yet the implications of his study tour cemented a serious change in thinking when it came to grazing management practices on his own property.

"I observed field trials in Adelaide, South Africa that involved pasture management and compared pasture, animal and economic performance ‹ these trials included continuous grazing (set stocking), rotational resting and rotational grazing, all at different stocking rates," he said.

"It really defied gravity in my opinion to see the continuous grazing at set stocking rates outperforming the others in economic terms hands down over the short and long term.

"It made me realise how important it is not to lose sight of animal performance while we strive for improved pasture production and performance, and while I accept those particular trials I strongly believe in the merits of rotational grazing and didn't believe it had had been given the best possible chance."

An example of the holistic mentality observed in South Africa was the time spent with a family in Vryberg who produced cattle in a cell-grazing system.

"Their strategy when it came to tick control involved the free-range chickens they kept on the property which had developed a soft spot for cattle tick ‹ a chicken herd of around 20-30 kept a mob of 500 odd cattle clean," he said.

"The cost of running chickens was negligible compared to the cost of regular dipping campaigns."

The threat of environmentalists and pressure groups in America was having an impact on American farmers, yet at the same time the news wasn't all bad.

"In California I observed the good work being done by farmers to build bridges with conservationist groups, the mindset has changed relating to range and waterland management and there was a strong focus on conservation practices to ensure a sustainable future," Brendan said.

"In the words of John Taylor, a Californian rancher, we can't just do as we please and this land is not ours to keep."


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