Category: CSIRO

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Sandy Soils – Sands Impact Validation Trial, Ouyen 2020

Background

Sub-optimal productivity is commonly reported for the deep sands that make up 20 to 30% of the cropping soils in the low rainfall Victorian Mallee region. Diagnosis of local constraints have pointed to low fertility and the physical restriction of rooting depth as the most likely constraints to production on sands in the Victorian Mallee. To explore this further, a trial was established at Ouyen in 2017 to investigate the potential the interactions between crop water use, physical disturbance by rotary spading, and the incorporation of organic amendments.

Methods

Treatments
Six different types of organic matter were incorporated to a depth of 30 cm depth in 2017 using a one pass spade and sow operation (Table 1). Each organic amendment was applied at a rate which supplied 2.5 t/ha of carbon, but varied in carbon:nitrogen (C:N) ratio. Spaded organic matter treatments were also compared to spading only, spaded urea (supplying equivalent quantity of N as vetch hay) and a non-spaded control.

Management
The trial was sown to barley in 2017 with subsequent years rotating between wheat and barley. Each season the trial received DAP S Z (16:17:0:8; 0.5%Zn) @ 62.5 kg/ha at seeding and 47 kg/ha of Ammonium Sulphate and a foliar application of copper, zinc and manganese was applied during tillering.

TreatmentApplication Rate (t/ha)C:N RatioTreatment N Input (kg/ha)
Spaded Vetch Hay616:1156
Spaded Oaten Hay5.972:135
Spaded Vetch + Oat Hay3.3 + 2.725:1102
Spaded Chicken Litter6.816:1218
Spaded Compost15.810:1252
Urea0.34N/A156
Spaded controlNilN/A–
Non-spaded controlNilN/A–
Table 1

Results

2020 Grain Yield

Here was a 0.75 t/ha increase in grain yield in 2020 between the non-spaded control and all other treatments which were spaded in 2017.  There was no significant difference between spaded treatments, therefore there was no effect of organic matter in 2020.

Cumulative Yield Benefit (2017-2020)

Spading chicken litter compost in 2017 has provided increased grain yield by 3.4 t/ha relative to the on-spaded control.  The effect of spading was 1.3 t/ha, therefore the long term yield benefit of the application of 6.8 t/ha chicken litter was 2.1 t/ha.  The next most effective organic matter source was compost while on-farm organic matter sources such as vetch hay has provided not provided long term benefit over and above spading.

Acknowledgement
This virtual field day has been developed as part of the Mallee Sustainable Farming (MSF) project:
“Facilitating enhanced knowledge sharing of Mallee sustainable farming practices”
This project is supported by the Mallee Catchment Management Authority (CMA), through funding from the Australian Government’s National Landcare Program.

The research featured in this virtual field day was completed as part of the Grains Research and Development Corporation (GRDC) funded project:
• Increasing production on sandy soils in the low-medium rainfall areas of the southern region.
The trials are a collaboration between Frontier Farming Systems and Mallee Sustainable Farming, CSIRO and UniSA.

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Sandy Soils – Sands Impact Validation Trial, Tempy 2020

Background

There is considerable interest in strategic deep tillage (e.g. deep ripping, spading) with or without agronomic amendments (fertilisers, organic matter) to overcome physical constraints and increase water and nutrient supply within the profile of Mallee sandy soils. To investigate the potential benefits of deep ripping and the inclusion of organic matter (OM), a replicated trial was established near Tempy in 2019.

Methods

Treatments
The trial comprised of five treatments to compare deep ripping only with inclusion plates and OM addition. All deep ripping treatments were implemented to a depth of 50cm with a tine spacing of 56cm. The OM used was a chicken litter compost blend, applied at 5t/ha (https://www.peatssoil.com.au), in the treatments listed in Table 1.

Management
The trial was sown to barley in both 2019 and 2020. Each season the trial received DAP S Z (16:17:0:8; 0.5%Zn) @ 62.5 kg/ha at seeding and 47 kg/ha of Ammonium Sulphate and a foliar application of copper, zinc and manganese was applied during tillering.

Depth cmTreatment
Control (undisturbed)––
Deep ripping50with rigid shank (Tilco)
Deep ripping50with inclusion plate (Tilco) operating 150mm below soil surface
Deep ripping50with inclusion plate (Tilco) plus OM surface applied
Deep ripping50with OM deep placed behind the ripping shank
Table 1

Results

2020 Grain Yield

Deep ripping with inclusion plates and/or OM applied produced a significantly higher grain yield than the undisturbed control in 2020. The grain yield of the deep ripping only treatment was not significantly higher than the control in 2020.

Figure 1: Grain yield from the Tempy site in 2020

Cumulative Yield Benefit (2017-2020)

All treatments increased the quantity of grain grown in 2019 and 2020 by at least 1.5 t/ha, relative to the undisturbed control. However, there is no significant difference in cumulative grain yield between the ripping treatments.

Acknowledgement
This virtual field day has been developed as part of the Mallee Sustainable Farming (MSF) project:
“Facilitating enhanced knowledge sharing of Mallee sustainable farming practices”
This project is supported by the Mallee Catchment Management Authority (CMA), through funding from the Australian Government’s National Landcare Program.

The research featured in this virtual field day was completed as part of the Grains Research and Development Corporation (GRDC) funded project:
• Increasing production on sandy soils in the low-medium rainfall areas of the southern region.
The trials are a collaboration between Frontier Farming Systems and Mallee Sustainable Farming, CSIRO and UniSA.

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