Carbon Drawdown Projects

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Biochar Trial

We conducted a Biochar Trial under non irrigated pasture. With 100kg and 200kg of biochar with 100kg and 200kg of Single Super. The full report can be found Here

Summary

Overall the biochar had a positive effect on both the plant biomass and minerals in the soil, with a statistical difference detected in the plant minerals caused by biochar.

Pasture Biomass

The biochar in general improved pasture biomass. In many cases the half fertiliser rates (100kg of urea) showed similar growth to the full fertiliser rates (200kg of Urea) indicating that the biochar may be holding nutrients in the soil allowing greater pasture growth.
Over 8 reliable pasture cuts there was more often an interaction between biochar rates than there were fertiliser rates and sometimes an interaction between both. When the seasonal factors were not limiting (ie November) it was more difficult to find a statistical difference.

Soil Tests

There was a general pattern of mineral retention in the soil with added biochar and the mineral retention was higher in the soil with half fertiliser treatments rather than full fertiliser treatments. These results were not statistically analysed.

Plant Tissue Tests

There was an increase in the amount of manganese in the plant tissue in the biochar treatments. This was the only statistical difference in minerals found in the plant tissue caused by biochar.

Feed Tests

No significant differences due to the biochar treatment were detected with the feed test result. Higher fertiliser rate had a small effect on increasing fibre but reducing fat content.

The below you tube clip discusses the trial and shows the trial being sown.

Replicated soil health trials 

Two replicated soil health sites at Willow Creek and at Yundi on the Fluerieu Peninsula of South Australia contained 4 soil health treatments, 1 farmer method and a control. They were monitored to find differences in soil health, plant health, feed quality, biomass and soil moisture.

This aim was to find and provide a better regional understanding of the impact of the alternative and chemical fertilisers on soil moisture holding capacity, growing season length, soil acidity and other soil health parameters such as microbial properties (mainly bacteria and fungi), organic C and pasture health and production.

We found that the cost of biological treatments compared well with chemical treatments and can be applied in larger rates biannually saving on application cost. In addition, the biological soil health treatments made substantial improvements in soil health and plant health and the biomass and feed testes compared well with chemical treatments The cost of biological treatments compared well with chemical treatments and can be applied in larger rates biannually saving on application cost. Specifically, the biological soil health treatments:

• Made a bigger difference when soil organic carbon was lower (such as at Yundi compared to Willow Creek)
• Built soil carbon when the soil organic C was lower
• Improved:
  • biomass
  • plant mineral uptake
  • nitrogen availability and mineralisation
  • phosphorus availability
  • pH, and
  • soil health indicators such as bacteria and fungi numbers.
• There were statistical differences in plant feed test results when comparing those treated with biological fertilisers vs chemical treatments.
• The cost of the minerals added to the treatments were in most cases beneficial as they were taken up by the plants.
• Some mineral elements where lacking in the soil need re application each year, while others do not. This is a case by case basis and there is more information in the report.
• The additional cost of biochar added to the FFF/S treatment have played a role in improving soil moisture and mineral availability, biomass, soil health and pH as this treatment was overall the better of the biological treatments.

A full copy of the report can be found  Here

5 Soil Health Case Studies

This project aims to provide a better regional understanding of the impact of the alternative and chemical fertilisers on soil moisture holding capacity, growing season length, soil acidity and other soil health parameters such as microbial properties (mainly bacteria and fungi), organic C and pasture production. The methods used: Five paired case study sites on farmer properties measuring soil health (paired means one site has a soil health or chemical treatment and the other a control). The treatments here have been established for a minimum of five years. It is important to note that the paired site is either a different paddock on the same farm or a different farm (next door). All paddocks are adjacent to their comparison. Care was taken to choose similar pasture species and soil types, but the grazing management was not the same and soil health treatments also different.

There was a range of grazing strategies and this influenced soil health and plant available water. The soil health was generally better where there were alternative fertilisers, however the soil health was well supported where there was a high grazing pressure and low grazing days. The soil biology was not as good where there was low ground cover and less plant species diversity.

The cation exchange capacity (CEC) was always higher on the biological sites supporting the transfer of nutrients from the soil to the plant. Denitrification was higher on high chemical N input sites. The pH of the soil was better in biological side irrespective of liming treatment

The report highlights the importance of grazing management, ground cover, and mix of pasture species in conjunction with biological fertilisers to support soil health. The final report needs a few small final edits pending feedback from the case study farmers and can be found Here