Irrigated cropping challenges to be tackled through new research

image of Irrigated wheat
The unique challenges faced by irrigated grain growers in Australia’s southern and northern cropping regions are to be addressed through a new suite of investments by the GRDC. Photo: Arthur Mostead

The unique challenges faced by irrigated grain growers in Australia’s southern and northern cropping regions are to be addressed through a new suite of investments by the Grains Research and Development Corporation (GRDC).

The GRDC is seeking applications for the delivery of a range of investments to support irrigated growers in their efforts to increase profitability from their cropping systems.

GRDC Manager Agronomy, Soils and Farming Systems – North, Kaara Klepper, says the four new investments are designed to provide irrigated grain growers with the knowledge, confidence and tools to adopt management strategies which optimise return on investment.

“The GRDC recognises that the challenges associated with growing crops within irrigated farming systems are often complex and that gaps exist in the provision of targeted research, development and extension (RD&E) to assist growers in overcoming those constraints,” Dr Klepper says.

“Substantial increases in water costs in recent times have magnified the issues confronting growers whose decision-making around crop selection, crop management and quantity of irrigation water applied to crops can have a significant bearing on gross margins.”

Dr Klepper says the GRDC has listened to the concerns of irrigated growers and designed this new research in a way that ensures growers have a hands-on role in ground truthing results.

“Growers and advisers will play a pivotal role in this suite of investments through facilitated action learning groups, which will allow them to influence research questions and ensure research meets regional needs,” she said.

“The groups will also provide critical links between growers and researchers, which will allow information to be shared and research results tested at a farm level, ultimately providing growers with tailored information and resources to better inform their management decisions.”

Irrigated cropping is an important component of grain production systems in the Murray Valley of northern Victoria, the Murrumbidgee and Murray Valleys of southern New South Wales, the South Australian-Victorian Mallee, the South-East of SA and Tasmania.

In recent times, growers in these regions have increased their focus on winter crop production systems that frequently complement summer cropping programs, seed production, horticulture or other high value crops, as well as new irrigation layouts and technologies to accommodate a diverse range of winter and summer cropping options.

GRDC Senior Manager Extension and Communication, Luke Gaynor, says significant gaps in knowledge exist regarding the true economically attainable yield potential of winter and summer grain crops in an environment where water supply can be manipulated to realise yields not possible in areas that are traditionally dryland production systems.

“In addition, the GRDC acknowledges that information and knowledge is sometimes lacking regarding the most appropriate agronomic practices to deploy in order to realise the genetic potential of commercially-available germplasm where water is no longer the limiting factor,” Mr Gaynor says.

The first of the investments, ‘Optimising farm scale returns from irrigated grains: maximising $ return per megalitre of water’, will build on the GRDC’s past irrigation investments to assist growers and advisers to make informed decisions to drive improved returns under irrigation.

Dr Klepper said growers will have the opportunity to benchmark, test and validate assumptions and key learnings arising from the new irrigation investments.

Real time data along with research findings will be used to generate an economic sensitivity analysis to quantify the economic impact of changes in water, commodity and input price, and irrigation method at the whole farm scale, allowing growers to evaluate cost: benefit scenarios.

The ‘Development and validation of agronomic practices to realise the genetic potential of grain crops grown under a high yield potential, irrigated environment in the northern and southern regions’ investment will involve on farm trials demonstrating agronomic practices which address priority constraints or opportunities for key crops in order to maximise system profitability.

This will include RD&E of practices aimed at optimising the return on nitrogen (N) spend through N form, timing and rate in the context of irrigation scheduling and inter-related agronomic decisions; studies into canopy management and prevention of lodging; foliar disease management; and other activities to better understand and inform grower decision making and consistently optimise yield (in the context of water price, input costs and commodity price) for the crops where gaps are most apparent. These crops include faba bean, chickpea, durum, canola and maize.

The ‘Increasing yield potential of irrigated crops in the northern and southern regions through novel amelioration techniques that improve soil structure’ investment will focus on addressing issues associated with soil constraints unique to irrigated cropping areas.

About 0.40 million hectares of poorly structured grey sodic clay soils and approximately 0.75 million ha of shallow transitional red brown earths exist under irrigation in the southern Murray Darling Basin.

These soils are prone to dispersion, poor water infiltration, waterlogging, impaired root growth and low natural fertility. In a recent study, only 30 percent of monitored wheat crops achieved more than 80 percent of their water limited yield potential, with waterlogging and poorly timed irrigation some of the key factors contributing to the yield gap.

This investment will investigate existing and novel soil management technologies to improve soil structure, infiltration and moisture retention on shallow and poorly structured red duplex soils, and sodic grey clays prone to dispersion and waterlogging in modern irrigation systems.

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