Agrisolutions Farm Experience

Year of study:

2006-11

Lead organisation & collaborators:

Gerhard Grasser

Contact:

Gerhard Grasser

T: (03) 5627 8663

Best available science assessment:

Objectives Conceptual model Study design Soil analysis Production & financial Method reporting Data analysis Results reporting Publication
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Project details

Objectives:

Farm experience with the development of a biological system soil management system for a dairy farming and free range pork operation. The aim was to improve the performance and persistence of pastures and improve soil, plant and livestock health.

Hypotheses:

Hypothesis is that the biological farming system will regulate its own pH. This method still accounts for nutrients and physical structure of the soil to ensure air and water holding capacity and accounts for organic matter levels in the soil and consequently the biological activity. Various forms of carbon and biology (bacteria- main earthworm food source). Earthworms – and other soil biology – can neutralises soil (pH) due to biological response. Air and water holding content affects pH.

Soils do not need lime unless calcium content is low. (Same for copper/phosphorus and most other elements whose plant availability changes with pH)

Basis of trial:

Holistic farming concept-biological systems. Management follows Allan Savory’s work (Holistic Resource Management).

Location details

Management practices tested:

Lime application (25kg/ha of superfine lime- liquid)

Biological systems

Trial site details:

Trial was commenced during a drought, which has subsequently broken. Initially the sub soil was dry. This meant after first lots of autumn rainfall- the new roots were shallow and the pasture ‘pulled’ when grazed. Aeration was conducted to channel water deeper to prevent this.

~1000mm/y (over 900 is good) rainfall. Four- five soil types, including greys to reds and sandy soils (a few in between).

Trial conducted over whole farm (in hill country). Some parts of property are steep. About 30-40 of 127 acres are not accessible by tractor.

Pre-trial management:

Previously pastures managed intensive for dairy production. Property is devoid of trees. They used rotational grazing and strip grazing in short rotation.

The theory is to use extended spell from grazing to allow plant recovery. Never denude the ground. We undertook mechanical resurrection of soil degraded in a sacrifice paddock, and used oats to build carbon and return the soil structure and function.

Silage crop. Winter crop of oats and millet for Summer. Pigs are used to root up the soil and then it is mechanically finished for seeding.

Lime used occasionally.

Trial management:

Now draw on Allan Savory’s work- extended rotational grazing- because it supports biological systems. 80-90 day rotation.

Pigs- 300 pigs rotational grass based (some grain)

Dairy- 80-90 day rotation & strip grazed (50 cows) (only grass based)

Hay and silage- initially cut as much as could be done, but now it is used standing in paddock. (It costs time and money to harvest and store. Sometimes silage was no sooner completed, then it was immediately fed out!)

Trial design:

Whole of farm.

Summary of key findings of trial:

Soil pH, a very basic measure of soil condition and plant nutrient availability, is so commonly associated with ‘a lack of lime’. Scientific research has found that pH is also driven by the aerobic condition of the soil, and the biology actively living and working in the soil. In fact, a recent discovery has been made that the bacteria or fungi attached to or in close proximity to plot roots affect the pH around the root to where it is near neutral – even if the surrounding soil is alkaline or acid. The microbes will regulate their own pH and also provide the mechanism for efficient uptake of nutrients at the appropriate pH for that plant. This is the direction in which soil managers must head as reserves of mined soil amendments (rock phosphate, lime, dolomite, etc) diminish and fossil fuels to mine, cart and spread them become more costly and in short supply

Treatment results:

Variation in soil C with time and management influence:

Expected to sequester carbon as the microbiological activity improved. Difficult to measure against seasons.

Variation in soil pH with time and management influence:

Earth worm numbers have improved- pH will self regulate according to seasonal influence and subsequent biological activity.

Other soil treatments:

Results of soil testing in 2006 and 2011:

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Soil structure improved. Compaction levels and plant species have changed- less weeds. Aggregation has changed and increased moisture content.

Variation in productivity/profitability with time & management influence:

Difficult to assess given starting point of trial during drought

Other measures of treatment response (e.g. water quality):

Earth worm numbers have increased. No herbicides used; there have been changes in pasture sward, and prominent plant species. Animal behaviour/health- indicative of the level of mineral content of food sources.

Method:

Soil sampling method:

Baseline sampling: > 1 sample per acre to standard 10cm deep for each soil type. Tested for available nutrients and exchange nutrients (SWEP laboratories in 2006)

Sampled as before. Last 6 months- tested for total nutrients as well as available and exchange nutrients. (EAL lab in 2011). This test of total nutrient analyses uses concentrated nitric acid extraction, which comes close to determining all nutrient reserves in the soil from which the plant can draw over a season or seasons.

Samples taken with 10 cm soil corer. Composite sample analysed. A sample per acre. Randomise across paddock. Sent in an overnight express bag to the lab where their standard analyses took place.

Production measurements

Stocked to the level of grass growth which required visual assessment of pasture to monitor.

Milk quantity measured.

Pig meat- building up breeding numbers over 3-4 years.

Hay and silage- baling and raking. Hay quality and quantity (comparative basis with neighbours as assessed by contractors).

Cost and value of production:

Fish and kelp and superfine lime recurrent @ $30/ha plus application cost. Mineral fertiliser as a capital application @$170/ha.

Details of cost and value of production can be obtained from farm records as necessary.

 

Reportage:

How results have been reported:

N/A

Note that an annual video recording of observations has been recorded on the property since it was purchased. This was taken by a professional 3rd party – Helen and Hugo Disler of Farming Secrets. They undertake to share the learning by landholders and experts with members of their webgroup so that other soil managers may apply an adaptation of this to their own farm businesses.

Next steps

Manage holistically and have measures in place to assess soil health as a precursor to plant and animal health and farm profitability.

Assess total soil nutrients from the outset, conduct microbiological baseline soil tests and take more accurate field records using a Soil Health Card.

Better record keeping.