Glomalin is a form of stabilised carbon found in soil. It is a glyco protein and acts like a glue, binding carbon, nitrogen and other biological components of soil to the mineral components, clay and sand.
It is produced by the hyphae of arbuscular mycorrhizal fungi (AMF).
It is believed that these fungi produce glomalin in order to support the hyphae in the soil.
AMF have a symbiotic relationship with plants, the fungal hyphae penetrate the cell walls
of the plant roots and bring nutrients and minerals to the plant from beyond the plants root zone. In return, the plants give up carbon based products to the fungi.
Very little is known about glomalin. It was only discovered recently (in 1996 by Sara Wright).
It is known that glomalin forms a major part of the soils stored carbon (20-30%), that it is stabilised (for 40 to 100 years) and that it binds other carbon based particles to the soil.
If farming could encourage AMF to proliferate then such farming practices would be carbon negative by encouraging high levels of glomalin in soil and thus regenerating soil carbon.
The symbiotic relationship between AMF and crops results in a greater amount of nutrients and minerals being made available to plants as the AMF extend beyond the root zone of the plants.
Food grown in symbiosis with AMF has a higher nutritional value than that produced under conditions that do not support AMF. This is because the symbiosis results in a wider range of nutrients (not just NPK fertilisers) becoming available to crops in the proportions required by the crops.
By binding the clay, sand and organic particles of soil together to form aggregates, glomalin helps to prevent soil erosion thereby reducing pollution and maintaining soil fertility levels.
The following factors should be met encourage AMF proliferation:
1, No or minimal digging of the soil. Digging breaks up the fungal mycelia and upsets the symbiosis between plant and fungus.
2, Permanent plant roots should be present in order to allow the symbiosis to occur.
3, Adding fertilisers (especially phospherous fertilisers) should be avoided as these can have a detremental effect on AMF proliferation.
4, Increasing atmospheric carbon encourages AMF proliferation.
5, Providing various habitats and conditions in the soil can encourage proliferation.
6, AMF Innoculation of the soil can be useful in speeding up colonisation of the soil. There are, however, many different varieties of AMF which proliferate in different soil conditions and in the presence of different plants. Home made innoculants made from local soils may, for this reason, be more effective than imported innoculants.
7, Adding appropriately made biochar encourages AMF priliferation.
The carbon capture farming page describes and compares various growing techniques which try to use these criteria to provide the bect conditions for AMF.