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
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.
Climate & Agricultural Support P/L 