Encouraging study results
Soil types across the Wimmera, Mallee and Grampians vary considerably from heavy clay to loam and sand.
All can present farmers with a variety of management needs and treatments.
Research is demonstrating that substantial opportunities exist to increase productivity of crops on poor-performing sandy soils.
Trials in a Grains Research and Development Corporation project have shown some sandy-soil treatments could deliver investment returns up to 520 percent.
However, researchers involved in the ongoing studies are advising growers to assess the potential to increase yields and any associated risks before implementing new treatments and practices.
The GRDC investment, ‘Increasing production on sandy soils in low and medium rain areas of the southern region’, is exploring cost-effective techniques to diagnose and overcome primary constraints to poor crop water use on about ¿YH PLOOLRQ KHFWDUHV RI XQGHU SHUIRUPLQJ VDQG\ soils.
The study is a collaborative effort involving CSIRO, Primary Industries and Regions South Australia, the University of South Australia, Mallee Sustainable Farming, Ag Grow Agronomy and Trengove Consulting.
CSIRO scientist Therese Mcbeath said research involved assessment of a spectrum of crop constraints and interventions across different types of sand and environments at several sites in Victoria, South Australia and southern New South Wales.
Interventions include application of soil wetters, improved fertiliser management, lime applications, deep ripping and more aggressive tillage, incorporation of clay or organic matter, and delving.
³7KHUH KDV EHHQ VLJQL¿FDQW ZRUN LQWR VDQG\ soils in recent years, and research has been separated into mitigation strategies, which are lowcost annual interventions that typically have a small impact on yield, and high-cost, high-impact and long-term amelioration treatments,” she said.
“This project aims to bring all these intervention strategies together, so when a grower is approaching a sandy soil on their farm they can think about all the options available, to decide what managePHQW SUDFWLFH LV EHVW IURP D ¿QDQFLDO DQG SURGXF tivity perspective.”
Dr Mcbeath discusses the research investment in a new GRDC podcast, at http://bit.ly/2ywmo7h.
In the podcast, she refers to results being generated from trial sites at Bute in South Australia, where treatments combining deep ripping with surface applied nutrition – fertiliser or chicken litter – delivered the highest marginal returns on a sandy soil.
These ranged from $934 to $1249 a hectare across three years.
Depending on treatment cost, these treatments delivered return on investment ranging from 142 to 521 percent.
While the results are encouraging, Dr Mcbeath said understanding the rain-limited yield potential DQG VHDVRQ VSHFL¿F HIIHFWV ZDV LPSRUWDQW IRU assessing the lscope of yield gains and the associated investment risk.
“The aim is to develop appropriate and costeffective management strategies with high returns and that are low risk, so growers can increase their actual crop yields closer to their yield potential based on rainfall,” she said.
Dr Mcbeath said season-to-season effects of different interventions were also important factors to consider when contemplating sandy-oil treatment options.
Through the GRDC research, characterisation of sandy-soil sites across Australia’s southern cropSLQJ UHJLRQ KDV FRQ¿UPHG WKDW FRPSDFWLRQ ZDWHU UHSHOOHQFH DQG D UDQJH RI QXWULWLRQDO GH¿FLHQFLHV are common issues.