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Composting

 

Leaf litter & organic waste

The first settlers of Auroville found barren wasteland devoid of topsoil, organic matter and plant life. Many settlements were started by drilling a well, putting up protective fencing, and then planting and watering. Climatic conditions are such that development of biomass is abundant wherever land is fenced against stray cattle and protected against theft and inconsiderate exploitation. Composting of leaf litter and organic waste is therefore fairly common in Auroville.

Anaerobic composting

Many community settlements and households have a composting site, either arranged in a pit for anaerobic composting, or in a heap or windrow for aerobic composting.

Anaerobic composting is, apart from digging a pit, practically labour-free. After many months - up to one year - the pit can be emptied and will yield a fairly well-matured compost. Depending on the season and the actual rainfall during the composting time, the end product may still have smelly anaerobic lumps and not be pleasant to handle. It might not be the right treatment for young & tender and sensitive plants or seedlings.

Aerobic composting in a heap yields, in general, a better matured compost, and this within a shorter period i.e. two to four months. But it requires more attention and labour. If properly built up i.e. with enough twiggy roughage as a base, aeration of the heap, and thus aerobic composting processes, is assured. It is recommended to turn the heap at least once, not for aeration, but for a thorough breakdown of thicker wood pieces. During a long dry spell, the compost heap should be watered. This kind of composting usually yields a fine, crumbly and pleasant end product. Its nutrient content depends to a large extent on the raw materials which have gone into the heap. The loss in nutrients is always quite big in this type of composting, but it is said to cultivate the soil organisms appropriate for the topsoil.  

Earthworms

Composting with earthworms – vermicomposting – was introduced to Auroville in the late eighties. It might be mentioned that every good aerobic compost heap harbours earthworms, but vermicomposting is set up in such a way that the worms can multiply optimally and do thorough processing of all compostable matter. The end product is a compost of ideal constitution and structure. A vermicompost unit has to be set up in such a way that the worms are protected against chickens, other birds and rodents. It also has to be protected against heavy rains and/or be extremely well-drained. Daily attention is a must, as a drop in ideal water content interferes with the optimal activity of the worms. Various earthworm species are being propagated as ideal candidates for vermicompost, but it is always possible to use the species which are locally available in Auroville, namely Lampito mauritii and Perionyx excavatus.

Another useful and valuable product of vermicompost is vermiwash, which is said to have growth-promoting and pest-repelling properties. In order to harvest vermiwash, the vermiculture is handled slightly differently.      

At present, AuroAnnam farm, Discipline farm, Revelation farm and a few individuals are known to practice vermicomposting. 

Biodynamic compost (BD)

Since 1997 biodynamic (BD) preparations made in south India have become available to Auroville farmers and gardeners.  Annapurna farm, AuroAnnam farm and Discipline farm have been the most active in their use. The BD compost preparations are made from various plants in contact with animal parts, and undergo an elaborate processing before they can be used. The preparations are put into the heap or windrow when it is completely built up and “sealed” with a skin of plant material e.g. coir fibres or cow dung slurry. They ensure an extremely thorough decomposition of the compostable matter and an end product of highest quality. Proper build-up, aeration, moistening, and at least one turning are required, as for any other aerobic compost.

The use of basalt meal – if available – or rock phosphate, of slaked lime, and of wood ashes is part of the BD compost, but may form part of any other (aerobic) compost, too. Bonemeal is, in principle, a very good substitute for animal manure, but its source and constitution may be dubious. 

Effective micro-organisms (EM)

EM technology – the use of a liquid culture of “Effective Microorganisms” – can also be used for composting. EM is sprinkled during build-up of the compost heap layer by layer. This type of compost can and should be used very fast – within two weeks - to achieve the maximum benefit from the organisms inoculated into the heap. The fact that lots of organic matter may not yet be decomposed is desirable in this case, as the propagation and metabolic activity of the organisms depends on the availability of carbon from organic matter.  

EM for composting is being used at AuroAnnam farm and Discipline farm.

In various regions of India other techniques of composting have been developed. Their characteristics are usually based on regional climatic factors and on availability of building materials and type of compostable matter. 

Comparison between BD and EM compost

All these forms of composting have their advantages and disadvantages. The products of higher quality are generally associated with more labour. The basic difference between BD compost and EM compost may be characterised as follows: BD preparations and BD compost are capable of building up long-term soil fertility and highest crop qualities while, in later years, requiring minimal input. EM technology and EM composting leads to very quick and obvious results as regards quantity and quality of yield, but requires input at higher frequency.   

Biomass

Because of the labour intensity of composting – mainly the gathering and transporting of materials – some farms try to replace it to a large extent by direct use of biomass on the fields i.e. by mulching and green manuring.

The Auroville Eco-Service operates a mobile desludging unit that can be called to desludge septic tanks and other sludge holding devices. The sludge is processed in pits by co-composting with carbon-rich material such as coir pith or wood waste and treated with EM. The compost produced is used in forestry. Presently the sludge pits are in the compound of the Botanical Garden, and their team collaborates in running the operations.

 

Contacts:

Regarding EM, BD, vermicompost – AuroAnnam

Regarding AV farms – Farm Group Office / Lloyd

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