ABC video discussing biochar and the circular economy
The project established that one animal does 8 to 12 dungs in a day covering 1 square meter and equivalent to a wet weight of around 20kg. Each plot roughly represented the manure of for one day only however was placed across the plots over 9 months with 9 dungs weighing 1.8kg each = 16.2kg/square meter of dung. In a recent trial with dairy and cattle (Rebbeck et al, 2019) there were 220 cows across 200 hectares which equated to roughly a spread rate of 10 tonnes/ha of manure across a year. We were aiming to measure what might happen to soil carbon over the space of a year if biochar was fed to cows on an average Adelaide Hills/Fleurieu Farm.
The trial treatments were nothing, dung only (buried by dung beetles), 100kg/ha of biochar and 200kg/ha of biochar under the dung and 200kg/ha of biochar in the dung.
Analyses of variances were performed on all of the data collected from the soil, and pasture and statistical differences were found in one or 2 factors of each of the elements of soil health, soil minerals, soil carbon, plant biomass, plant minerals and feed test values.
In particular, statistical differences in treatments were found with improved performance in the biochar treatments for pasture biomass, mycorrhizal fungi, organic carbon, sodium, phosphorus and sulphur in the soil. For the plant data, statistically different improvements were found in the plant biomass, sodium and molybdenum and for the feed tests digestibility of organic dry matter % and Megajoules of Energy mg/kg of DM. The treatment with 200kg of biochar in the dung performed the best followed by the 200kg of biochar under the dung.
While there were also factors of each of the measurement elements that also did not show statistical differences, the trends of better values and improvements in soil health, minerals and plant health, biomass and feed value were similar to those showing statistical changes with the treatment of biochar in the dung at 200kg/ha being the most favourable to soil health and plant health and production and the plots with nothing at all being the least beneficial.
It was not expected to find so many significant differences in the biochar treatments compared with the dung only treatments. Dung beetles do play a very important part in this project, however the project demonstrated the additional benefit that biochar can have on soil. In particular if biochar is fed through an animal or applied to manure, it can have a large effect on soil health, soil minerals and soil carbon within 1 year. The soil carbon results showed that translated to tonnes of soil carbon means an improvement of 4 tonnes/ha of carbon. Under the Emission Reduction Fund and current carbon prices as at the end of Oct 2021of $31/tonne ACCU would mean a pay back to farmers $455/hectare (NB 4 tonnes is multiplied by 3.67 to get to ACCUS). This is not a bad result for 9 months.
The exciting part of this project is 2-fold
- You can feed biochar to animals and gain a production improvement (the biochar is maintained in the dung).
- You can use dung beetles to then bury the biochar laden dung through the soil profile to gain exacerbated benefits on soil health, soil mineral availability, soil carbon, plant minerals, plant feed test and plant biomass.
The research report can be found here
Click on the link for the technical report {Tech Report Link}
Published or read the summary report below
Biochar Dairy Feeding Trial
This involved:
Measuring 6 weekly milk yield, protein, fat, ICCC compared with long term data across 4 dairies.
Manure pH, and other properties
Soil health (burying biochar)
4 x dairy’s of 250 cattle at Fleurieu Milk Co
1 fed Biochar type 1 90ml/head/day but issues with other additives
1 fed Soft Agriculture – Pty Ltd – Mara Seeds Pty Ltd 200gms/head/day
2 dairy’s without biochar
A link to the technical report can be found HERE
Biochar Dairy Feeding Trial 2
A second biochar dairy demonstration trial was conducted over a 2 year period in the Goulburn Broken Catchment of Victoria. It had very similar findings to the first dairy trail with additional farmer observations.
Full Report Can be downloaded here
In addition to the improvement in milk yield and quality the farmer found
- No more bloat (despite high protein)
- No occurrences of mastitis and usually is cases found.
- Fed less hay in winter, around 2 bales less
- No acidic smell of cow dung so rumen more settled converting feed a lot better
- New young heifers look the best for a long time.
Dung beetles were reared on 10 farms in the Goulburn Broken Catchment of Victoria. There were varying levels of success with rearing and releasing these dung beetles with dung beetles likely to persist and populate on 5 of the 10 farms. These beetles will then infiltrate the district where properties have neighbouring cattle. Where less success occurred breeding and releasing dung beetles, flooding or over irrigation occurred or not enough rainfall late summer.
There was evidence of improved soil carbon and soil minerals in the soil as a result of feeding biochar through the animal. These results align with a fully replicated research trial completed by the same project manager (Rebbeck et al 2022) and a further dairy feeding study completed on the Fleurieu Peninsula (Taherymoosavi et al 2022).
The feeding biochar method to cattle and using dung beetles to bury the laden manure has been proven to reduce nitrous ox ide emissions which are 300x more potent than CO2. This will also limit the excess nitrogen from running into nearby waterways which causes reduced water quality and can increase nutrient load and algal blooms especially in this study as many properties are very close to the Murray river.
Further work is required to demonstrate how fast manure burial by dung beetles can reduce nitrous oxide emissions. In addition, further work is required to show how biochar can reduce methane emissions by feeding it to cattle. However some evidence of methane reduction might be attributed to better feed conversion due to the reduction in the amount of fodder fed at the farm that persisted with biochar feeding. There are papers published that show the correlation between better feed conversion and methane reduction (Leng 2013).
This project will add a potential economic benefit to the region as biochar when fed to dairy cows has been demonstrated to improve production on farm by around 10pc per year. In the case of RL the benefit of both milk yield improvement and soil carbon payback was roughly $60,000 per year. In addition, once the dung beetles fully expand across the properties, they were reared on they will continue to improve soil health by returning nutrients and carbon to the soil; increasing water infiltration and holding capacity; and improving soil structure (reducing compaction) and improving pasture health and yield.
Further follow up work could occur to re measure the pasture tissue, feed test and soil health values on Richard Lazarotto and Craig Emmet’s farm. Increased soil health through improved nutrient, carbon and water cycling has result in improved pasture production in similar studies. In addition, evidence provided by Doube and Marshall (2014) has shown that by using dung bee les to bury dung, less worm larvae are present on the soil surface resulting in less worms being ingested by cattle and a reduced need to worm cattle.
Three of the farms in this study had their soil carbon baselined and registered under the Emission Reduction Fund. They are likely to also have follow up auditing done with opportunities for farmers in the region to learn from their management practices. These results need to be treated with caution as they are not statistically replicated. This was a demonstration trial only.
It is estimated that at least 1000 other dairy farmers and farmers in the region and across the Australia became aware of the benefits of biochar and dung beetles with over 2000 farmers likely to change practice or advise to change practice.
This project could contribute greatly to the Australian Government pathway of 100 billion dollars in farmgate output by 2030.
Full Report Here
Soils Research
In addition we have conducted a number of soil based research and demonstration trials with biochar. A summary of results presentation can be found HERE and a link to the research results can be found here – SOIL HEALTH PROJECTS
Project Summary – Full Report Here
This project aimed to improve soil carbon, pH and minerals by applying Jeffries biochar compost mixes to soil.
The results showed that the biochar amount with or without the composts had an impact on the organic carbon content, likely due to its high carbon content of biochar (up to 80%). The more biochar present the higher the organic carbon in tonnes/ha. The more biochar present also the higher the gravimetric moisture. This is likely due to the water holding capacity of the biochar.
The ECEC was impacted upon positively by the addition of compost and the higher the biochar in the compost and the higher the application rate the better the ECEC. This then resulted in higher amounts of cations in the soil in the compost and biochar treatments including magnesium and calcium with the addition of compost being beneficial. The JBC treatments did better than the biochar treatments alone.
It would appear that the JBC treatments or biochar did not impact on Ammonium but the organic JBC impacted on Nitrate (that can be converted from organic N).
The copper levels were generally lower in the nothing plots and higher in the treatments.
The zinc levels were higher in the treatment of the Randell Rd paddock and highest in the JBC supercharged treatment but there were only minor differences.
The availability of minerals were impacted by the JBC treatments but the pasture type also had an impact.
The phosphorus level in the soil was always higher where the biochar was with some additional impact with the organic JBC blend.
The biochar had an impact on the level of heavy metals with or without the compost.
The addition of compost to the biochar had a greater impact on the soil mineral content than biochar alone (in most cases). However, it would have been beneficial to test just compost to test the differences. The organic compost appeared to have a greater effect on N and P availability regardless of the pasture present and would perhaps be the better of the 2 blends however a higher amount of biochar in the organic blend may have additional benefits.
In conclusion the aim of the trial to improve soil carbon, pH and minerals by applying Jeffries biochar compost mixes to soil was achieved to varying degrees.
Carbon Drawdown Projects 