Method of Applying Biochar in Avocado Farming

Biochar was applied at 5%, 10% and 20% (volume basis calculated on a depth of 500 mm). The biochar was applied in two applications. The first half was applied at a depth of 500 mm and a 250 mm layer of subsoil placed on the biochar which was incorporated with a rotary hoe. This process was repeated with the second half of the biochar applied and the topsoil replaced on top, followed by rotary hoeing.

Two rows of 36 trees were planted, with each tree planted 4.5 m apart and each row 9 m apart. The first row was the control, and the second row contained the biochar.

Trees were planted in early December 2014, all with the same under tree fertiliser mix. . Trees were also mulched with a mixture of chicken litter, hardwood sawdust and wood chips. Both the biochar and control rows were on the same line for irrigation and had exactly the same water allowance.

Results

From the visual and measured observations, trees planted with biochar had 18–26% greater growth rates than the control with no difference between the various application rates of biochar. Fruit yield however, gave a different result. The 5% and 20% of treatments give significantly more fruit on average than the control and the 10% treatment. This indicates that there could be different interactions between the biochar, soil mineral and organic matter, added fertiliser in the 10% treatment than in the other two treatments which could partly account for the lower yield.

Economic Benefits

The study indicated that there was a net benefit of US$105 for every tonne of biochar applied and the average net profit per tree was US$35.

This farmer designed trial has demonstrated that biochar can significantly improve the growth of avocado seedlings and increase fruit yield. This is an important study and crucial to development of the biochar industry in Australia. It provides evidence that biochar has environmental and economic benefits to the farming and horticultural sectors. Read more about biochar boosts yields in Avocado farming.

We are very pleased to announce that we have received funding from Innovation Centre WA to conduct biochar emission testing on our pyrolysis process. The biochar emissions testing is very important in the commercialisation of our technology and will provide invaluable feedback going forward.

We are focusing the biochar emission testing on two industries where our technology could be utilised, poultry farms and waste water treatment. This funding will enable us to perform biochar emissions testing on sewage sludge and poultry litter and use this information as a preliminary investigation on the likely pollutants emitted from the plant and as an indication on plant performance.

Poultry Farm Biochar

Poultry farms produce significant amounts of poultry litter (a mixture of manure and bedding material). Currently, birds are grown in sheds on 7 week cycles. At the end of each cycle, the litter is removed and stockpiled until there is sufficient quantity to transport away where it is spread on agricultural land as a fertiliser. This stockpiling attracts flies, emits odors and releases greenhouse gases. There are also increasing food safety and environmental concerns about its application on agricultural land in un-modified forms. There are currently no alternatives to this treatment.

Bio-solids Biochar

The waste water treatment industry produces an enormous quantity of sewerage sludge (bio-solids). Sewerage sludge contains heavy metals, is classified as a hazardous waste and must be disposed of carefully, generally at significant cost. Our technology is ideally suited to process sewerage sludge n site to produce a non-hazardous biochar.

The information gained from the biochar emission testing will enable us to manage further development of the kiln in terms stack emissions before conducting a comprehensive full scope of testing according to the Waste Incineration Directive (WID) under the Environmental Protection Act. Comprehensive testing will be critical when we begin to build our first project.

The biochar emission testing will include:

The preliminary testing (if positive), will enable us to show various stakeholder (such as investors) that our prototype meets Australian Emission Standards. And, if negative, give us the information we will need to make changes to the kiln in order to alleviate the problem.

Energy Farmers Receive Biochar Trials Funding

We are pleased to announce our application to the Northern Agricultural Catchments Council (NACC) to run biochar trials has been successful.

The aim of the biochar trials will be to demonstrate potassium response to the application of wheat straw biochar to soils in a cereal crop.

Many Australian farmers burn crop residue to control chemical resistant weeds. There is however an opportunity to capture this residue to produce bioenergy and biofuels. To achieve this outcome, it is important to understand how the by-products of the bioenergy process, such as biochar will affect our cropping systems.

Farmers on soil types low in Potassium import potassium in the form of Muriate of Potash (MOP) to use in wheat crops. Since wheat straw is quite high in Potassium, we will ask the question, is there is potential to mine Potassium from soil types typically high in Potassium, process the straw through pyrolysis to produce bioenergy and biochar and use the biochar to replace potassium in a cropping regime? This trial will test this hypothesis.

The biochar trials will also include treatments of biochars made from waste resources (such as chicken manure) blended with traditional fertilisers to ascertain yield response. The demonstration site is Northampton shire, Western Australia. The soil is a typically, lower performing loamy sand. It is moderately acidic with low levels of Nitrogen, Phosphate, Potassium and Organic Carbon.

We have engaged Grant Thompson from Crop Circle Consulting to carry out the biochar trials.

The trial will consist of small plots, each of approx. 0.004ha for each treatment. Each plot will be seeded with a small cone seeder. There will be a minimum of 4 reps for each treatment and include:

• Control (No treatment)
• Standard farmer treatment with traditional fertiliser
• Up to 8 biochar or biochar blend treatments – We have not finalised the treatments at this stage. Biochar would applied either under (deep banded) or with the seed.

Biochar will be produced from locally source wheat straw, shredded and pyrolised by Energy Farmers and analyzed for nutrient and carbon content by The University of Western Australia.

Drivers

Firstly, we were engaged by Chandala Poultry to design a system that would recover the energy from chicken litter the farm produces and use it to meet the farms energy requirements. We did look at other bioenergy technologies including anaerobic digestion but decided, after consultation with the owner, on pyrolysis.

Secondly, technologies to produce biochar in Australia are either too big, needing thousands of tonnes of feedstock to be viable and a very high capital expenditure or the smaller, cheaper technologies, a little underdeveloped.

The final and key driver to start building a biochar kiln was that we wanted to demonstrate bioenergy technology to farmers. We believe that bioenergy and the valuable byproducts produced by the process complements agriculture and closes the nutrient loop. Most farmers have not had the opportunity to visit a bioenergy plant so we decided to bring bioenergy to farmers.

Beginning the process

After making the decision to begin building a biochar kiln, we sourced a design that would meet our requirements:

• Simple and user friendly
• Affordable
• Continuous flow
• Able to be made mobile for demonstration purposes.

We then contacted various Geraldton based (trying to keep it local) firms capable of building a biochar kiln and asked them to quote on materials and some construction work. It was our aim to get the components built and do most of the construction of the biochar kiln ourselves, this way we get to know the machine inside and out.

In the beginning of 2013 we started building the biochar kiln and after some testing quickly found a few issues that needed to be addressed. These included:

Maintaining heat

It is critical to be able to maintain heat inside the biochar kiln for the pyrolysis process to take place. In the beginning, we used minimal insulation and because of this we were losing a lot of process heat. After we addressed this problem we were able to get to operating temperature quickly and maintain the temperature where it was needed, inside the pyrolysis chamber.

Gas vs diesel

Initially we were using LPG gas to heat the biochar kiln however, after looking at the issues and regulations associated with using gas, we decided to use a burner fired on diesel to provide the heat needed to get the process going. We find it easier to manage logistically, just as efficient and a lot safer to operate.

Course material

As we are using augers to move the feedstock into and through the biochar kiln, unless it is ground quite fine we can have some issues, the longer pieces wrap around the auger shafts and can block the auger. This necessitated purchasing a tub grinder which we will use to grind organic materials like wheat straw and wood chips.

Moisture content

Feedstock moisture content is also very important. If the moisture is too high then the process does not work and we have to use a lot of energy just to dry the material to a point when it will char. This is inefficient and not what we are trying to achieve. The ideal environment for the biochar kiln is to use an external heat source to heat the chamber then be able to turn it off and rely on the incoming material to provide the energy necessary to maintain the process, this is renewable energy.

This particular problem meant we had to come up with a way to dry the material before we processed it. After long debate we designed and engineered an internal drying system. The dryer is an auger we have installed inside the kiln above the pyrolysis zone. We load the material via a loading auger which feeds into the dryer where it moves along very slowly. The moisture is driven off by the heat produced by the biochar kiln as it moves through the dryer.When it reaches the end of the drying auger the material drops out into the pyrolysis auger.

This auger completes the biochar process, gases bound up n the material are released as the material turns to biochar. These gases are then combusted in the gasification zone to create heat.

Where are we now?

Since the upgrade last month we have run the kiln a few times but like anything new, we have had a few teething problems. Namely, with heat expansion and some manufacturing issues with the drying auger. We believe we have sorted out these issues and are looking forward to testing the process again soon.

Stay tuned for updates or contact us to learn more.

Energy Farmers Australia is pleased to announce the development of our first mobile biochar kiln. The kiln has been in the pipeline for well over a year and we have just finished construction. We are in the process of commissioning the unit and expect to have it operating in the next couple of months.

This unit is mobile and will process approx. 200-300 kg/hour. Initially we will use it to produce biochar for field trials and to demonstrate bioenergy technology to farmers and farmer groups throughout WA.

How the Biochar Kiln Works

The process uses a diesel burner to heat the chamber, we then introduce biomass via a single screw auger. As the biomass moves along the chamber it heats and the gases bound up in the biomass are released. Initially, we will flare the gases however, we plan to utilise the gas to produce electricity during the next phase. We have a number of thermocouples throughout the kiln to monitor the temperature. We also have the ability to introduce water to the kiln which we can use to regulate the operating temperature and to quench the char.

Building the Knowledge of Biochar

We will be testing the process with a range of different feedstocks to determine biochar quality, yield and energy output. We are in the process of identifying markets for the biochar however, in the shorter term we will be offering the char to farmers, farmer groups and other interested parties to conduct trial work. This trial work will be invaluable going forward and important to the uptake of biochar production and the development of the biochar/bioenergy industry. We are also developing a life cycle assessment of the biochar kiln process, investigating the carbon farming opportunities under the Carbon Farming Initiative and seeking environmental approvals.

Energy Farmers intends to keep the agriculture and bioenergy community informed about the development of the kiln through updates on our website, the International Biochar Initiative and Bioenergy Australia. You can also contact us to find out more information.

West Australian agricultural cropping systems have wheat straw in abundance and at the moment we are not utilising this resource to our and our communities’ advantage. Wheat straw for bioenergy is a feasible option and Energy Farmers is working to develop projects that use wheat straw for bioenergy.

Current situation

Most farmers in Western Australia are cropping year in year out. Wheat, canola and lupins grown in rotation gives farmers the option of using alternative chemicals to take out weeds however, chemical resistance is still an issue. Burning crop residue is one option that farmers have to break that weed seed cycle but this is where we are missing the opportunity, the straw is literally going up in smoke.

When talking about burning we are only speaking about burning the harvest rows, not the whole paddock. During harvest farmers direct the straw coming off the sieves and rotors into a narrow row and then come back in March or April and burn these rows. Harvest trials carried out by Energy Farmers in 2011/12 in Mullewa show that straw yields of 1 tonne of straw for every 1 tonne of grain are achievable by bailing this harvest row with a conventional baler.

Capturing the resource

While conventional bailing is OK, we believe the best option to capture the resource is with the Glenvar Bale Direct. The Glenvar system is a baler connected to the back of the harvester. The system uses a belt to move the material from the harvester to the baler where it is baled normally. We understand the concerns farmers have with this system. Balers are complex, need skilled operators and using the system will probably slow down harvest. However, the advantage of using the system is that residue and weeds are collected in a one pass operation.

Wheat straw is typically around 15-25% moisture and has a net calorific value of around 13-15 MJ/kg.  It contains nutrients such as potash however, has high amounts of silica which gives a relatively high ash content which and can lead to slagging and fouling problems during the combustion process.

Being a low density product, transport is an issue and one of the biggest limitations for any bioenergy project. Bale weights need to be kept to a maximum to alleviate this problem as well as sourcing straw for bioenergy projects close to where the facility is to be built.

Conversion technologies

Some of the emerging technology options to produce bioenergy and biofuels from wheat straw include:

Cellulose to ethanol – which is microbial or enzymatic conversion of biomass materials through fermentation. Fermentation involves microorganisms that use the fermentable sugars in biomass for food and in the process produces ethanol and other byproducts.

Pyrolysis – there are two types of pyrolysis fast and slow. Fast pyrolysis occurs between 300-550C and occurs in less than two seconds. The process produces a vapor which, once condensed turns into a fluid called pyrolysis oil. This oil can be used as a fuel source for boilers but needs to be further refined into transport fuels.

Slow pyrolysis occurs at around 400C and has longer residence times. The process releases the gases bound up in the biomass. These gases can be burnt to create heat or scrubbed (cleaned) to use in a gas fired motor driving a turbine.

Nutrient value

The nutrient value of the straw is also very important. If farmers are going to be removing straw from their paddocks then they will be also removing nutrients and these nutrient will need to be replaced. It does not make sense to us to replace these nutrients through fossil based fertilisers. Instead by-products of these conversion processes such as biochar can be used to replace the nutrients as well as pick up carbon credits through carbon storage or offsetting fossil based fertilisers.

Energy Farmers has been doing a lot of work on the feasibility of using wheat straw and other crop residues for bioenergy production. If you would like more information please contact us.

As part of Energy Farmers Australia’s vision to see biochar integrated in Australian farming systems, we are looking at the options to get biochar back into the soil in Australian agricultural systems.

Biochar is hard to handle, it can be powdery in which case it does not spread well. It also takes a lot of processing to get it into a form (granulation and pelletising) that can utilise farmers existing equipment.

While char does not spread well, it will be an option in broad acre cropping systems where farmers are using mouldboard ploughs to reduce the impact of non wetting sands and resistant weeds. Spreading the char and then ploughing will bury the char up to 400mm underground and looks to be a very simple yet effective way to incorporate the biochar through an existing operation. Spreading and ploughing will work well on sandy soils however will not be applicable on soils that mouldboard ploughs cannot be used. So we need to look at other options.

We have teamed up with Wayne Phillips and his new machine the New Horizon Subsoiler Extruder. Subsoiling involves adding a medium (e.g. water) to biomass, in this case char and deep banding it into the soil. The subsoiler can handle a range of biomass from manures to straw and will open up myriad of opportunities to blend char with different feedstocks, potentially offering an alternative to traditional fertilisers.

While the subsoiler is still in development stage we are very excited about its potential. We will be trialling the subsoiler this season with biochar and other forms of biomass.

Here’s a sneak peak of what it can do, stay tuned for updates.

http://youtu.be/A2l57g44sxU

The International Biochar Initiative (IBI)  have released their final DRAFT biochar guidelines for biochar production. These guidelines provide a standardized definition of biochar and biochar characteristics related to the use of biochar as a soil amendment.

They will serve as the basis for IBI certification  programs, and are intended for use and adaptation to local conditions and regulations by any nation or region.

These guidelines support not only baseline safety considerations but also the evolving understanding of the positive functions of biochar in soil.

Good news for the development of biochar in Western Australia (WA). Read about IBI’s Biochar Guidelines and more about what the IBI are about.