FROM China's changing diet and its impact on greenhouse gases through to tactical control of cabbage aphids in canola, the University of Western Australia (UWA) Institute of Agriculture postgraduate students are covering a wide range of topics as part of their on-going studies.
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The students were under the spotlight at the 2016 postgraduate showcase last week, sharing their research projects with industry and other academics.
Research into sheep fertility and genetics features strongly, with two students showcasing their work in the area.
UWA postgraduate student Joseph Steer focused on identifying odours that attracted lucilia caprina, the blowfly species that causes flystrike in sheep.
Mr Steer's research, supported by the Department of Agriculture and Food (DAFWA) and Australian Wool Innovation (AWI), compared various odours present in sheep susceptible and resistant to flystrike.
By testing fly responses to these odours, Mr Steer is hoping to identify which are attractive or repellent to blowflies.
"Long-term, the research could form part of sheep breeding programs to build flocks with odours that are less attractive to blowflies," Mr Steer said.
Controlling flystrike costs the sheep industry $280 million a year.
Student Anna Aryani Amir gave a snapshot on her research, investigating how new pastures affected sheep reproduction, which could lead to identifying particular plant compounds that boost fertility.
Ms Amir said despite an increased awareness in testing forage for its negative impact on reproduction, there was little research on how pastures could positively influence fertility.
Using in vitro maturation (IVM), a procedure where immature eggs are collected from a ewe's ovary and matured in the laboratory, Ms Amir added various plant compounds from chicory, albo tedera, red clover, subterranean clover and lucerne pastures to test the whether they had an effect on reproduction.
The results from Ms Amir's study have shown that a compound from Biserrula legume pastures gave a significant 20 per cent increase in fertility efficiency rates.
A tactical approach to managing cabbage aphids in canola is the focus of Dustin Severtson's research.
There is no defined sampling plan for cabbage aphids in canola, with farmers generally using a preventative method to control the pest.
Cabbage aphid can cause wilting, flower abortion, reduced seed set and affect canola oil.
"A tactical approach in sampling cabbage aphids could mean that growers can spray when required rather than as a precaution," Mr Severtson said.
His work involved releasing cabbage aphids in trial plots and establishing the movement of the pest on individual plants and throughout the crop.
The research showed that in the first week of release, aphids colonise the underside of the canola leaves, before moving onto the racemes (branches) by the third week.
By week seven, there had been an exponential population growth with aphids visible throughout the plant.
Mr Severtson said using a sequential sampling methodology and splitting a paddock into different regions could help reduce the need to spray an entire paddock if only one area had been affected by aphids.
"Once 20pc of plants are infested with aphids, this is when growers should act and spray,"he said.
Mr Severtson is looking at developing a mobile application to help growers ascertain when to act.
Student Nathan Craig presented his findings on nitrogen mineralisation in a long-term, no-till situation, using data gathered from a trial site at Cunderdin in 2013 and 2014.
Mr Craig looked at two cropping rotations, one of wheat, chickpeas and canola versus a monoculture of wheat over the same period.
His research showed that crop rotation can add an additional 44 kilograms of nitrogen per hectare, compared to a monoculture rotation.
Over the two seasons the trial took place, Mr Craig's research showed that nitrogen limitations affected yield more than disease.
In 2013, the trial had a third higher root disease and three times higher leaf disease levels, however there was no difference in yield between the monoculture and rotational plot.
In 2014, the rotation with additional nitrogen produced more heads per square metre compared to the monoculture plot.
Abdulkareem Alsih's research in the hydrology of water repellant soils has allowed people to identify and monitor water repellant soils using non-invasive methods.
Mr Alsih's research has also shown for the first time the dynamic breakdown of water repellant interfaces in the soil.
It is hoped that his research will help improve the understanding of the physics of water movement in the soils, offering the industry an insight into new ways to manage water repellant soils on farm.
Taking a global approach, student Jacob Hawkins studied how China's dietary changes from 1989 to 2009 influenced greenhouse gas emissions.
Using data from the United Nations Food and Agricultural Organisation, Mr Hawkins split data into 15 food categories and examined the correlation between food type and the greenhouse gas emissions.
A 701pc increase in milk consumption led to a 659pc increase in emissions, while a 466pc increase in fresh fruit led to a 210pc increase in emissions over the 20-year period.
Mr Hawkins said while beef consumption had increased by 592pc, the lower increase of 202pc in greenhouse gases was due to greater efficiencies in the industry.
"Overall, China's per capita food consumption is still considerably lower than other developed countries such as the United States," he said.
"There is still a great divide between the dietary habits of rural and urban China, which helps balance the overall consumption number."
Greenhouse gas emissions by China's trade partners were also examined in the study.
"New Zealand's food exports to China increased four fold over the 20-year period and its exports to China count for 10pc of New Zealand's overall greenhouse gas emissions," Mr Hawkins said.
Rebecca Owusu's study focused on the adoption of new innovations in agriculture.
"Feeding the world requires successful technologies based on informed research, so it is important that these technologies have the attributes that would appeal to farmers,'' she said.
Ms Owusu focused on technology adoption rates in Africa, surveying 306 farmers and using the data to sort farmers into four classes that established their main drivers and how this impacts on their decisions to take up new technologies.
