Aeration Pasture cropping and extended grazing trial

Lead Organisers and Collaborators:

Maffra & Districts Landcare Network

 

Contact:

Malmo Street Maffra

PO Box 727

Maffra – Vic – 3860

ABN: 88 065 838 078

Phone: 1300 094 262

E: maffralandcareoffice@gmail.com

Web: www.landcarevic.net.au

 

Context:

In 2010, the West Gippsland Catchment Management Authority commenced a project titled; Healthy Soils Sustainable Farms – building carbon and managing pH in West Gippsland.

The project has been supported by the three years of funding from the Australian Government‘s Caring for our Country program with the five Landcare Network’s that operate within the West Gippsland region engaged to deliver soil health information to their respective communities.

As part of the project delivery approach, the Maffra and District Landcare Network instigated a series of farmer workshops focussed around the basics of soil health management and production related issues.

Based on a group learning model, the establishment of paddock demonstration sites was identified as being a critical learning component to assist farmers in following up on their theory based workshop learning.

More importantly, it was recognised that conducting on farm demonstrations would provide the most effective way of positioning those farmers involved in the project with the best information to make realistic on farm management decisions and to adopt new soil management techniques relevant to their own farm enterprises.

This case study provides some background to the property ‘Ballyo’ one of the three properties in the Maffra and District Landcare area where a paddock focussed demonstration site has been established.

The case study outlines the soil and pasture constraints identified within the focus paddock on ‘Ballyo’ and provides a summary of the remedial techniques that are now being tested and trialled.

Consideration of the treatments undertaken during the first year of the demonstration and the related observations are also provided.

It is envisaged that this on farm demonstration site story will be updated as the various treatments and their results continue.

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Project details

Objectives:

Based on the paddocks identified constraints and the landholders interest to undertake soil aeration, the purpose of the demonstration site at ‘X” and the various treatments chosen have been undertaken to test, observe and make considerations to the on farm management actions that should;

  • Improve soil aeration
  • Increase soil water holding capacity
  • Encourage more vigorous and deeper plant root growth
  • Encourage preferred summer active perennial grass species establishment, growth and persistence
  • Increase overall seasonal ground cover %
  • Increase soil carbon levels

Management considerations:

  • The strategic use of Yeoman’s Plough should improve soil growing conditions to better support water holding capacity and plant root growth.
  • The introduction of an additional summer active C4 perennial grass (Premier Digit) should assist to provide an alternate and more persistent summer feed source.
  • Extended grazing management should encourage preferred perennial grass populations to recover and aid deeper & more vigorous plant root growth.
  • The combination of above actions would collectively help to improve soil conditions, pasture diversity and soil carbon levels.

Property Profile

‘Ballyo’ is a 140 acre property located at Kilmany and is predominately a dryland beef grazing enterprise although some irrigation infrastructure is available for seasonal pasture watering and crop production. The current owners purchased the 140 acre property in 2004 and operate the property as a beef breeding property with weaner calves being sold into local store markets.

Grazing management can be described as moderately intensive through the strategic use of the properties 35 rotational based paddocks that are serviced by a central laneway.

Rye grass based pastures are grazed on a 3 leaf cycle with the more perennial dominated pastures having a longer rotation. Rainfall at ‘Ballyo’ nominally averages 600mm per annum but consistent with East Gippsland’s rainfall, is inconsistent in its pattern.

The soil characteristics of ‘Ballyo’ and in particular the demonstration paddock can be described as being duplex silt loam with salt and sodic characteristics.

 

Soil and production constraints

As part of the healthy soils project, each participating farm identified what they considered to be their ‘worst’ paddock in terms of soil health and production constraints.

Paddock number 7, being a paddock of approximately 5ha was selected on “Ballyo” as a result of the following attributes:

  • A moderately compacted soil profile along with the landholders interest to undertake aeration.
  • A lower than desired % distribution of summer active species leading to summer feed gap issues

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Paddock history:

The demonstration paddock is know as back paddock no 7 and is approximately 5 ha in area.

The area the paddock encompasses was formerly 2 larger paddocks that have now been subdivided into 7 smaller paddocks.

The topography of the paddock is nominally flat with a slight southerly aspect.

Lime was applied to the paddock prior to the commencement of the demonstration.

Applied treatments and management actions:

Demonstration plots were established on the 26th April 2012.

To develop baseline evidence, transect quadrat assessments were recorded and soil samples taken for independently laboratory testing.

The treatment paddock was then aerated to a depth of six inches using a Yeoman’s Plough.

On the 30th April 2012, water monitoring tubes were installed near the centre of the northern transect line in the control area and another within the treatment area.

Water monitoring commenced on a semi regular basis using a Diviner 2000 probe and data logger.

On the 5th September 2012, the treatment area was again aerated to a depth of 6inches. The rip line this time being placed in between the previous aeration tyne lines.

During this operation, Premier Digit seed was distributed via a shank pot seeder mechanism mounted above each tyne of the Yeoman’s with seed dispensed at a rate of approximately 0.9kg/ha.

Year 1 – observations/results

The character of ground cover for both the control and treatment area changed significantly over the 10 month period. This is largely due to the well below average rainfall experienced over the period resulting in a feed shortage leading to the sites being severely grazed.

Looking at the control results first, winter grass species dropped significantly from 58.8% to 13.1%, while summer grass species increase slightly from 9.4% to 10.5%.

Legumes effectively disappeared, while broadleaf plants decreased from 15.6% to 4.3%.

These changes were offset by the increases in bare ground (from 0% to 28.8%) and the substantial increase in mulch from 6.3% to 43.4% explained in part by green foliage converting to mulch due to the drought like conditions and severe grazing.

The results of the treatment area also show declines in winter grasses (41.8% to 16.9%) and summer grasses (9.32% to 3.8%).

Legumes (mainly white clover) declined substantially from 43.1% to 0%. Unlike the control the level of broadleaf plants remained relatively consistent. These changes were offset by the increases in bare ground (from 0% to 40.3%) and the substantial increase in mulch from 0% to 33.1%.

The higher level of bare ground in the treatment is likely due to the aeration activity and the higher percentage of white clover in the paddock to begin with and the increase in mulch is again attributable to green foliage converting to mulch due to the drought like conditions and severe grazing.

The Premier Digit seed distributed in the treatment area during the second aeration process early September 2012 appears to have failed to establish.

This is somewhat understandable given the conditions (dry and sever grazing) although some plants were recorded to have germinated outside of the treatment area but were in poor condition and few in number.

The method of sowing may have also been a contributing factor to the poor establishment as the process did not result in the creation of an ideal seed bed for the fine Digit seed.

The soil moisture monitoring highlighted the declined of soil moisture over time across all profile depths considered as a result of either capillary action or direct root extraction.

As plant moisture requirements exceeded rainfall recharge, the soil profiles became exceedingly depleted with moisture levels across all profiles remaining constant over the summer period suggesting the soil reached a permanent wilting point and total available water had been extracted from the soil profile during this period. Overall the soil moisture monitoring data confirms the paddock was in ‘drought’.