AF Digest

Concentrated fungal stubble digestor ideal for cellulose and lignin degradation

AF Digest is a 100% fully soluble powder that contains a specific blend of natural fungal species, known for cellulase and lignin decomposition, perfect for naturally degrading the cellulose and lignin that make up residual plant material. Stubble has a particularly high percentage of lignin, which is very slow to degrade in normal conditions however, once degraded, produces high quality humic – rich materials, which increase soil organic matter and support plant and soil microbial growth.

Available pack sizes


Total analysis %

Bacillus amyloliquefaciens
Bacillus licheniformis
Bacillus megaterium
Bacillus pumilus
Bacillus subtilis
Phanerochaete chrysosporium
Trichoderma reesei
Maltodextrin carrier
8.64 x 10⁸ cfu/g

The benefits

  • Contains a carbohydrate bio stimulant to promote the initial growth of the microbial population. This is a slightly more complex carbohydrate which also encourages initial fungi growth.
  • The microbes are able to process organic materials in the soil as well as applied organic and inorganic fertilisers, making these nutrients readily available to the plant.
  • Contributes to the natural soil carbon and Nitrogen cycles.
  • Improves floc formation in the soil, increasing natural aeration and drainage.
  • Frees locked up nutrients in the soil, making them available for plant growth.
  • Has the potential to enhance the quality of produce by enhancing shoot and root length.
  • Approved for use in organic systems (OF&G Organic)

Understanding the synergistic microbes in AF Digest and their individual traits

AF Digest is a blend of synergistic bacteria and fungi, developed to break down the woody material left behind after harvest and improve the growing conditions in the soil for the following crop. Post-harvest stubble tends to remain on the ground for a long period as the cellulose and lignin degrading fungi that carry out this degradation do not easily establish in ploughed and heavily managed agricultural soils. AF Digest adds high numbers of the fungi that are amongst the most efficient at breaking down lignin and cellulose increasing the organic content of the soil and the level of inorganic and micronutrients. It also contains microbes able to release phosphorus and micronutrients to the plant as well as fixing atmospheric nitrogen. In combination, certain of the bacterial and fungal species can degrade residual chemical pesticides as well as some of the allelopathic chemicals released by plants into the soil to prevent the growth of competitive plants. When they accumulate in the soil, these chemicals adversely affect the growth of subsequent crops.

Bacillus amyloliquefaciens = is a non-pathogenic, gram positive rod soil bacterium, closely related to the species Bacillus subtilus. Similar to other Bacillus species, Bacillus amyloquefaciens is capable of producing endospores allowing it to survive for extended periods of time. It has been shown to be effective against several root pathogens that hurt agricultural yields in soil.

Bacillus licheniformis = is a gram positive, mesophilic, soil bacterium which can resist harsh environments. It is a spore forming soil organism that contributes to nutrient cycling and has antifungal activity. High capacity of secretion of the alkaline serine protease has made Bacillus licheniformis one of the most important bacteria in industrial enzyme production.

Bacillus megaterium = is a gram positive, endospore forming, rod shaped bacteria and is amongst the biggest known bacteria. It is considered aerobic, is found in soil and considered a saprophyte. It is able to produce a variety of proteins and sources of bioremediation, has been recognised as an endophyte and is a potential agent for the biocontrol of plant diseases. Nitrogen fixation has been demonstrated in some strains.

Bacillus pumilus = is a gram positive, aerobic, spore-forming bacillus commonly found in soil, water and other habitats. Some colonise in the root area of some plants where Bacillus pumilus has antibacterial and antifungal activity. Bacillus pumilus participates in a wide range of symbiotic relationships and can function as a plant growth promoting rhizobacteria within the rhizosphere. It is significant to ecosystem biochemistry because it functions as a nitrogen fixing bacteria capable of metabolically transforming molecular nitrogen (N2) into ammonia (NH3).

Bacillus subtilis = supports plant growth. As a member of Bacillus, this bacterium often plays a role in replenishing soil nutrients by supplying the terrestrial carbon cycle and the nitrogen cycle. Bacillus subtilis bacteria form rough biofilms, which are dense organism communities, at the air and water interface. Bacillus subtilis biofilms are beneficial and they allow for the control of plant pathogen infections. Bacillus subtilis biofilm communities form a mutualistic interaction with plant rhizome systems. The plant benefits because Bacillus subtilis provides pre-emptive colonisation.

Phanerochaete chrysosporium = inoculation has been proven to be an efficient method to promote lignocellulose biodegradation. Indigenous fungal communities, the most important organisms responsible for mineralisation and decomposition of lignocellulosic materials, can be affected by biotic factors. Extensive growth of Phanerochaete chrysosporium or other lignin-degrading fungi on unsterile straw would be excellent for inexpensive solid substrate systems intended for degradation of pesticides.

Trichoderma reesei = is a mesophilic and filamentous soft-rot fungus that can secrete large amounts of cellulolytic enzymes (cellulases and hemicellulases). Cellalases and hemicellulases from Trichoderma reesei has been shown to be powerful enzymes for biomass conversion to sugars (glucose).

Creating AF Digest

AF Digest contains a synergy of select biology, with a known performance within the soil, with the security of genetic integrity of the selected microbes by obtaining specific strains from the registered ‘genetic banks’. To provide biology that best fits certain scenarios, research and field trials are carried out to determine the effects of individual microbial species and their synergistic effects within the soil.

Our fermenters are both ISO 9001 and 14001 accredited and carry out a range of quality control checks for microbial counts and contaminants. The viability of microbial products are also tested to well in excess of the pressures used in spraying equipment 60 – 700 bar to ensure ease of use.

The strains we use in this product were originally sourced from accredited repositories. As we carry out a continual programme of product improvement by selective cultivation, our strains our sent back to the German DSMZ culture collection to carry out multi locus sequencing to confirm that the microbes we are using are still the same species (selective cultivation slightly changes the genetic make-up of the microbe so this is a part of our standard quality control). Once the species has been confirmed, because of the slight genetic changes from the original, it is a assigned a new, unique strain number. This is why we can state that we use unique selected strains in our formulations.

Application method


MIXING: Never prepare more spray solution than is required. Suspend the required dose of AF DIGEST in water, as 1 volume of AF DIGEST in 5 volumes of water. Mix thoroughly. Add suspension to required amount of water to obtain final drench volume. Apply the day of preparation.
DOSE RATE: 20g/ha

Apply in wet conditions. Once applied, the stubble/debris should be incorporated into the top 7-10 cm of the soil surface.