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CSIRO trial confirms BioAg approach

Wheat grown using biological farming practices has outperformed conventional wheat in almost every measure in a CSIRO trial conducted at Griffith in south-western NSW in 2004.

The biologically-grown wheat not only matched a conventionally-grown crop in yield but was more robust, had more developed root systems, flowered earlier and had fewer weed and disease problems.

CSIRO Plant Industry Research Agronomist, Dr Maarten Stapper, investigated the biological management as part of an irrigated wheat evaluation project funded by the Grains Research and Development Corporation.

Biological farming seeks to restore the soil’s active humus layer by adding “biologically-active” nutrients and beneficial micro-organisms, thereby producing a living, healthy and balanced soil for optimum plant and livestock productivity.

Ten varieties of wheat were sown on two adjacent blocks. One block was farmed conventionally while the other was managed according to biological practices.

The conventional wheat plots were treated with a seed treatment and sown with 150 kg/ha of DAP. During the growing season, they were top-dressed twice with urea and sprayed with a herbicide to control weeds dominated by stinging nettle and wire weed.

By comparison, the key nutritional ingredient in the biological blocks was BioAgPhos, a reactive rock phosphate that has been treated with a proprietary microbial culture.

According to its manufacturer, about half of the 15% phosphorus content is available immediately for plant use, while the remainder is slowly digested by the micro-organisms and added to the nutrient reservoir in the soil.

The improved soil microbial activity is also claimed to help unlock phosphorus, calcium and sulphur already in the soil, leading to long-term benefits in soil structure and fertility.

BioAg also markets a range of fermented liquid cultures which, like BioAgPhos, deliver a range of essential nutrients and metabolites directly to the plants and introduce beneficial microbes into the soil

BioAgPhos was applied to biological blocks before sowing, along with small amounts of monoammonium phosphate (MAP), sulphate of ammonia (SOA) and lime to balance nutrient availability.

The seed was treated with nutrient/microbial liquid, BioAg Soil & Seed, at sowing. The resultant crop was sprayed three times with the fermented liquid cultures, BioAg Balance & Grow and BioAg Fruit & Balance

Dr Stapper’s report, which can be found on the GRDC website, stated that fewer weeds emerged in the biological block, grew more slowly and were ultimately crowded by the closing crop canopy without the need for herbicides.

While both blocks had the same number of shoots at early stem elongation, the biological wheat flowered an average of two days earlier. Stripe rust was more prevalent in the conventional wheat, which also had a lodging score twice that of the biological wheat.

Measurements using a Plant Anchorage and Stem Strength (PASS) gauge showed that substantially more force was required to pull plants over in the biological block than in the conventional one.

Likewise, root samples taken after flowering showed the root systems in the biological wheat were thicker and more developed. “Balancing the physical, chemical and biological soil conditions seems to have a significant impact on root growth and anchorage strength of plants,” the report stated.

The biological and conventional blocks both recorded an average yield of 5.7 tonnes/ha, even though the former received only one-third as much nitrogen. The highest yielding varieties were Chara (6.7 t/ha in the biological block) and Rubric (6.4 t/ha in the conventional block).

The report stated there was mounting evidence that biological farming systems enhanced biological activity in the soil. “This is visible as a humus layer and improved tilth, and can result in substantial fertiliser and pesticide savings in three to five years.

“If soil contains the correct set of organisms, plant growth can be enhanced to the point that typically little or no pesticides and extremely low fertiliser rates might be required to obtain equal or higher yields than conventional practices

“If the balance of micro-organisms is wrong, fertilisers and pesticides can’t help recover plant vigour. Healthy soils grow healthy plants. Improved soil organic matter with soil organisms create a sponge which facilitates nutrient storage and availability, water holding capacity and retention, and better infiltration.

“Plants have better root growth and less tractor power will be required for essential management activities. Wind and water erosion will be reduced because of the enhanced aggregate stability.”