Merredin research paves the way

Countryman

Research and development undertaken by the Department of Agriculture and Food in Merredin over the past 40 years has been vital for the achieving improved yields and profits, even in very dry seasons, farmers were told yesterday.

On the occasion of Merredin Research Station's 100th field day, Grains Industry executive director Mark Sweetingham said the department's research station remained at the forefront of research into agriculture, playing an important part in much of the advice and technology made available to growers in the eastern Wheatbelt.

"In 1969, Western Australia suffered a serious drought which decimated crops, resulting in very little wheat being harvested. In 2010, an almost identical dry season was experienced across the Wheatbelt, yet growers averaged nearly one tonne per hectare of wheat," Dr Sweetingham said. "The reason for the difference in wheat yields, under very similar seasonal conditions, is that during the intervening 40 years, research and development by the department in partnership with an innovative farming community resulted in the adoption of better varieties and better crop production systems."

Dr Sweetingham said many of the advancements in cropping hinged on the advent of minimum tillage, which revolutionised the way crops were sown.

"Today's seeding systems have unlocked earlier sowing opportunities on less opening rainfall events which results in greater water-use efficiency and generates higher yields," he said.

Prior to the start of minimum tillage research in the mid 1970s, crops were sown using three full cultivations - two to turn the soil and kill weeds and a third cultivation to sow the seed.

Over time, these cultivations destroyed the soil structure, making them significantly more vulnerable to wind and water erosion and reducing rainfall infiltration rates on certain soil types.

"In contrast, minimum tillage involves just one pass to sow the crop into standing stubble, causing minimum soil disturbance, and weeds are controlled using herbicides," Dr Sweetingham said.

"Long-term research at Merredin demonstrated that the use of minimum tillage in continuous cropping systems improves soil structure and water holding capacity.

"Investigations by soil scientists, agriculture engineers and agronomists at Merredin found that some heavy soils responded well to gypsum application.

"This led to the department developing a simple test that growers could use to determine which soils would respond well to gypsum.

"In combination with minimum tillage, the use of gypsum improved the structure and yield potential of many cropping soils in the eastern Wheatbelt region."

During the past 25 years, research at Merredin has kept abreast of new advancements in minimum tillage technology, testing the effectiveness of different seeding systems and how best to manage the retained stubble and herbicides associated with the system.

"In 1978, 40,000 hectares were seeded using minimum tillage and this increased to one million hectares in 1982-83," Dr Sweetingham said.

"Today, more than 90 per cent of growers in the Wheatbelt seed their crops using minimum tillage techniques."

Department Grains Innovation Networks director David Bowran said minimum tillage was made possible through the widespread release in the mid 1970s and 1980s of broad-spectrum herbicides that enabled farmers to easily control weeds.

"Research at Merredin at the time reinforced the importance of consistent spray cover to control weeds," Dr Bowran said.

"Critical factors for herbicide efficacy were identified, including using the correct spray under the right weather conditions and maintaining and calibrating boom sprays.

"This stimulated broadscale practice change, with growers adopting best practice spray operations and maintaining boomspray systems to ensure effective operations."

The sensitivity of new crop and pasture varieties to herbicides was also researched at Merredin and recommendations about rotations and herbicide use were developed for farmers.

Recent research on the importance of summer weed control for storing soil moisture for crop use has been integral to farmers developing the confidence to control summer weeds.

Dr Bowran said the introduction of minimum tillage meant that crop stubble was no longer buried in the soil, as had been the case under full cultivation.

"The presence of stubble made it difficult to sow the following crop and to overcome this, farmers burned the stubble each autumn before seeding," Dr Bowran said. "But removing stubble increased the risk of erosion and made cropping soils difficult to work when wet.

"In the early 1980s, research started at Merredin to determine the best way to manage retained stubble so that soils were protected and farmers could sow crops with ease.

"The work found that retained stubble helped moisture to penetrate into soils and reduced evaporation on fine-textured soils, resulting in substantially increased yield when compared with areas where stubble had been burnt."

Dr Sweetingham said precision agriculture, or the ability to accurately auto-steer seeders, sprayers and harvesters using GPS technology, had generated significant savings for farmers in fuel, fertilisers and chemical inputs.

"Researchers at Merredin were among the first in Australia to investigate yield mapping using GPS technology," Dr Sweetingham said.

"A yield monitoring system imported from the United States identified that certain soil types could not sustain high yields and growers could save money by limiting fertiliser inputs into areas with low yield potential.

"The research also identified that several years of yield maps were required before the true yield variation across a paddock could be quantified."

Dr Sweetingham said the department's crop variety research was fundamental to advancements in cropping in the Wheatbelt.

With the development and widespread adoption of minimum tillage, growers could seed their crops several weeks earlier because they only had to perform one pass rather than several cultivations to sow seed.

This meant the growing season was extended by several weeks and consequently, crop-breeding programs adjusted by developing longer-season varieties.

"Merredin was involved in evaluating new varieties such as Westonia, Wilgoyne and Wyalkatchem for yield and disease resistance under eastern Wheatbelt conditions and, with the higher use of herbicides in cropping systems, for herbicide tolerance," Dr Sweetingham said.

"Introducing new, higher-yielding varieties remains one of the most cost-effective ways to raise farm profitability.

"Without the concerted wheat breeding efforts of the past 30 years, WA wheat yields would be 30 per cent lower and farmers would be hundreds of millions of dollars worse off than they are today."

Much of the current work at the Merredin-based Managed Environment Facility is aimed at providing plant breeders with the genes to continue to develop higher-yielding crop varieties suited to the drying climate of the eastern Wheatbelt.

Dr Sweetingham said the need for a breakcrop for wheat diseases led to lupins becoming a major component of minimum tillage continuous cropping systems on light soils through the late 1970s and 1980s.

"The inclusion of lupins in the rotation lifted wheat yields by contributing soil nitrogen however, early lupin crops were susceptible to root rot and work began on understanding the seeding systems needed to minimise root rot," Dr Sweetingham said.

"Using a high-speed camera to film lupins being harvested, department researchers demonstrated that a considerable proportion of lupin pods remained un-captured following harvest.

"Engineering research led to the department developing a new harvesting system for lupins by working with machinery manufacturers to alter harvesters for lupins."

Dr Bowran said with the opening up of high aluminium, lighter agricultural land (Wodjil soils) in the eastern Wheatbelt in the 1960s, soil acidity became apparent as an issue.

"Research at Merredin quantified the extent of the problem and demonstrated the value of adding lime to reduce acidity and lift crop yields," Dr Bowran said.

"Later work identified that cropping and fertiliser practices were causing gradual acidification of once neutral soils," he said.

"This led to a major research, development and extension program being established to quantify the extent of the issue, develop management packages and extend the results to local growers."

While legume pastures based on subterranean clover had been an important component of mixed farming systems in the eastern Wheatbelt since the 1960s, there were few pasture legume options for the range of acidic soils in the area.

Focussed pasture and rhizobial inoculants research at Merredin in the 1980s and 1990s saw the development of new burr medic cultivars Serena and Santiago, which were widely adopted across mildly acidic loam soils.

These hard-seeded cultivars were well suited to intensive cropping rotations and enabled higher stocking rates while reducing the need for fertiliser nitrogen in subsequent wheat crops.

Dr Bowran said the development of MIDAS (Model of an Integrated Dryland Agricultural System) enabled researchers to examine 'what-if' scenarios on the productivity and economics of dryland farming systems.

"MIDAS was developed at a time when the area dedicated to cropping in Western Australia was being expanded," Dr Bowran said.

"The system helped users to assess the impact of farm decisions on the economics and productivity of dryland farming systems.

"It captured the valuable contribution of legume nitrogen to subsequent crops and countered the view that the most profitable farming system was continuous cropping - leading to the development of effective legume-crop rotations."

Dr Sweetingham said the department remained committed to investing in research and development and assisting growers to access the best technologies available from Australia and the world.

"The Managed Environment and New Genes for New Environments facilities are concrete demonstrations of the bright future in cutting edge research and development being done in agriculture," Dr Sweetingham said.

"They stand as a testament to our confidence and belief in ongoing growth opportunities and the strong future of the sector."

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