Soil Productivity with Naturally Occurring Additives

Year of study:

2007

Lead organisation & collaborators:

Reg Gum PLains Soil Health Group

Meat and Livestock Australia CSIRO Land and Water

 

Contact:

Kate Simpson or Rick Robertson

T: 03 5157 8225 or 03 5157 7516

E: ksimpson@wideband.net.au

Best available science assessment:

Overall score: 24

Overall rating: High

Objectives

Conceptual model

Study design

Soil analysis

Production & financial

Method reporting

Data analysis

Results reporting

Publication

4

3

2

3

2

3

2

3

2

Project details

Objectives:

The project’s objective was to increase beef/lamb production by 10% (or 10 kg live weight per hectare) on the Red Gum Plains of Gippsland by improving the biological activity of soils..

Exploring soil health using naturally occurring additives

Project objective was to increase beef/lamb production by 10% (or 10 kg live weight per hectare) on the Red Gum Plains of Gippsland by improving the biological activity of soils in order to achieve healthier more productive soils, pastures and animals.

Hypotheses:

The trial’s hypothesis was that improved biological activities would improve the productivity of soils, pastures and animals.

The additives used in this trial (poultry manure, brown coal, molasses and compost tea) may improve soil productivity, pasture growth and weight gain of livestock.

Restoration of missing DNA (i.e., missing soil micro-organisms and their enzymes) could be accomplished with applications of poultry manure and compost tea, but perhaps not with brown coal and sugar, substances lacking living soil micro-organisms. It is possible that brown coal will stimulate existing micro-organisms. It is also possible that the “missing” micro-organisms are present on the demonstration farms but in such low numbers that they were not sampled earlier. If so, is it possible that the additives might change soil conditions to benefit these micro-organisms and permit their increase?

These trials sought to investigate how beneficial micro-organisms can foster and sustain higher productivity as well as engage the broader community on soil health.

Basis of trial:

Micro-organisms are an important component of soil health. This trial focused on restoring or improving biological conditions to benefit productivity.

Locations details:

Trial site details:

Dry climate during trial (East Gippsland sites).

Forge Creek

Bairnsdale (BoM) 641.4mm/a

Bengworden

Meerlieu (BoM) 620.7mm/a

Llowalong

Stratford (BoM) 616.4mm/a

Briagolong

Briagolong (BoM) 665mm/a

Pre-trial management:

Each property where the demonstration was conducted is a broad acre grazing property in East Gippsland

Rotational Cattle grazing on two sites.

Rotational Sheep grazing on two sites.

 

Trial management:

The four farms in the Forge Creek, Bengworden, Llowalong and Briagolong areas hosted the demonstrations. Molasses, compost tea, poultry manure and brown coal respectively were applied to seven hectare paddocks (recommended by Soil Foodweb Institute based on soil samples collected in April 2007) and comparisons were made with a similar sized control treated the same as the rest of the farm.

Summary of key findings of trials:

The demonstration was effective in communicating and resulted in farmers and field day attendees developing more knowledge surrounding soil biology.

The brown coal trial saw a 10% weight gain, however this was on the control rather than the treated paddock. The landholder felt it wasn’t worth the money to apply it in future. However brown coal may provide benefits over the long term beyond this trial period.

There wasn’t much different on pasture growth across the trials, but climatic conditions have likely contributed to that outcome.

 

Treatment results:

Variation in soil C with time and management influence:

N/A

Variation in soil pH with time and management influence:

Not evaluated

Other soil treatments:

Bacterial and fungal communities in the soils were significantly different between farms – the largest factor determining the species of micro organisms present was the farm the soil originated from. This is consistent with much of the literature.

For each farm, significant shifts in the types of bacterial and fungal species occurred over time. This temporal effect was also mirrored in the changes of key diversity indices (richness and evenness) for the microbial communities. The significant ‘time’ effect may have been due to adverse climatic conditions during the 2007-2008 seasons.

Within each farm, changes in soil microbial species composition and diversity of the communities were evident in some treatments. Caution should be exercised in interpreting these changes as it was not possible to undertake tests for significance at the treatment level.”

Variation in productivity/ profitability with time & management influence:

There was no measurable increase in weight gain or pasture growth.

Experimental design:

Treatments:

The four farms in the Forge Creek, Bengworden, Llowalong and Briagolong areas hosted the demonstrations. Molasses, compost tea, poultry manure and brown coal respectively were applied to seven hectare paddocks (recommended by Soil Foodweb Institute based on soil samples collected in April 2007) and comparisons were made with a similar sized control treated the same as the rest of the farm.

Trial design/layout:

2 seven hectare plots (selected by landholder)

Reportage:

How have results been reported:

Technical Report

How copies of relevant reports be obtained:

Kate Simpson, 03 5157 8225

Level of review of results:

N/A

Soil sampling:

Soil samples collected in April 2007. DNA sampling was used to characterise the response of microbial communities as a result of the organic treatments. Soil samples were also collected at the beginning and each year of the trial and tested at the Soil Foodweb Institute, SWEP and Pivot.

Samples were collected over a three year period.

Other soil tests were undertaken but were unable to be compared due to sampling timing, methods and different technical approaches between tests.

Tests were undertaken at:

  • CSIRO Land and Water (Australasian Soil and Plant Analysis Council (ASPAC) accreditation) (DNA tests)
  • SWEP laboratories (Australasian Soil and Plant Analysis Council (ASPAC) accreditation)
  • Soil Foodweb Institute

 

Plant and/or animal production measurements:

Grazing weight gains and pasture growth was measured as part of the demonstration.

Weight gain differences were difficult to attribute due to lower than average rainfall. There was no measurable weight gain across the demonstration sites.

There was no measurable pasture growth across the demonstration sites.

In addition, management activities included trial planning, actions, meetings, soil testing decisions and reporting. Communication activities included field days, farm walks, seminars, workshops and media releases prior to and following events.

 

Cost and value of production:

No information, however soil DNA testing found to be expensive.

Next steps

Communications around soil biology and soil health more broadly (apart from the specific focus of the trial) were the main impacts of the project. By understanding soil health and soil biology landholders will be better positioned to make good management decisions.

 

 

Much of the lessons learnt were provided through field days with speakers (Pauline Mele notably). Specific improvements suggested in the report include:

  • improved focus of demonstration
  • better selection of tools
  • set achievable objectives
  • clarify objectives
  • support for farmers
    • to interpret technical information
    • to provide guidance
  • match tools with monitoring objectives

These included that the DNA testing of soil was expensive (instigated by work done with CSIRO). Nobody understood it, wanted to do more work with it.

Some of the soil attributes couldn’t be compared due to issues with the soil sampling. However this would be a useful exercise.

Although the group has found the trials to be challenging, the benefits have outweighed the negatives. Therefore the group would recommend others being involved in similar projects.