Increasing production on sandy soils in low and medium rainfall areas of the southern region

 

Project code: CSP00203

Project manager: Dr Melissa Fraser

Project duration: July 2018 to June 2023

 

About the project

There’s close to 5.0 M ha of sandy soils in the low to medium rainfall areas of South Australia, Victoria and southern New South Wales with biological, chemical and physical constraints that limit crop yields. Despite improvements in crop management and agronomy, recent studies have shown that there is often a large gap between the potential yield (based on rainfall) on sandy soils and what is actually grown in most years. 

The key soil constraints to rooting depth and water extraction include physical (natural/traffic induced compaction and hard-setting) and chemical (pH, toxicities) impediments to root growth, low nutrient supply and biological cycling, water repellence and poor establishment. These constraints rarely occur in isolation and together result in poor root growth and crop water-use, which are the key drivers for crop yield and productivity, especially in the low rainfall zone. 

In 2016 the GRDC invested in a new Research Program to assist grain growers in the southern region to identify and overcome the primary constraints to poor crop water-use on sandy soils in the low-medium rainfall environment. 

In 2018 the Impacts Program was launched, with the objective of validating the outcomes of the Research Program across the south-eastern region, enabling targeted mitigation and amelioration techniques to be tested or demonstrated on a commercial scale to overcome diagnosed constraints on sandy soils.

MFMG have been working in collaboration with PIRSA to deliver two new trials in the upper South East east as part of the Impacts Program. The first site at Sherwood is located on a deep sandy rise that has previously had clay spread and incorporated in the top 10 cm; it was diagnosed to be compacted below 20 cm and deficient in potassium. The trial aims to treat the compaction by comparing soil mixing with a rotary spader with deep cultivation using a Yeomans Plow and assessing the crop yield responses, with and without potassium applied. The site was sown to wheat in 2019, and observations will continue in 2020 in beans. The second site at Malinong is located on a sandy crest that is severely water repellent in the surface, and acidic and compacted in the sub-surface. The trial compares the impact of soil mixing with a rotary spader and Plozza Plow, versus deep cultivation at 30 cm and 40 cm with an Ausplow ripper. Barley was sown in 2019 and observations will continue in 2020 in canola. The trials were monitored for plant establishment and harvest grain yield and quality; results for both trials are published in the MFMG annual results book. A third site will be established in 2020 at Talopea Downs in collaboration with the Wolseley Ag Bureau.

Project activities

MFMG have been working in collaboration with PIRSA to deliver three new trials in the Upper South East as part of the Impacts Program.

1.  A trial at Sherwood (near Keith) is located on a deep sandy rise that has previously had clay spread and incorporated in the top 10 cm; it was diagnosed to be compacted below 20 cm and deficient in potassium. The trial aims to treat the compaction by comparing soil mixing with a rotary spader with deep cultivation using a Yeomans Plow and assessing the crop yield responses, with and without potassium applied. The site was sown to wheat in 2019 and observations will continue in 2020 in beans. 
2.  A trial at Malinong (near Meningie) is located on a sandy crest that is severely water repellent in the surface, and acidic and compacted in the sub-surface. The trial compares the impact of soil mixing with a rotary spader and Plozza Plow, versus deep cultivation at 30 cm and 40 cm with an Ausplow ripper. Barley was sown in 2019 and observations will continue in 2020 in canola.
3.  A trial at Telopea Downs (Vic) traverses a shallow sand over clay, trending to very deep sand over the crest of a dune. The site had previously been clay spread at 200-250 t/ha in 2007, which was incorporated in the top 8-10 cm and has been in a long term lucerne pasture ever since. In 2020, a spader was used to re-incorporate the existing clay to 30 cm, to test if deeper incorporation is beneficial for crop growth. A second application of clay was also applied as a treatment (an additional 250 t/ha), which was also spaded in. The site has been sown to canola.  

The trials will be monitored for plant establishment and harvest grain yield and quality; results for all trials are published in the MFMG annual results book. MFMG annual spring field walks will visit the sites.

 

This project is funded by:

 

Project Resources:

Impact of deep tillage on penetration resistance, repellence and crop growth at Malinong Case Study