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Further Reading

Appendix 7C

Compostable waste

Some wastes provide excellent opportunities for reducing costs of fertiliser or soil amendment, or of waste transport, by spreading on the land, or by composting on-site or at a centralised facility. In some cases, combining wastes from different farms or farm processes provides a good basis for compost.

Care is needed to ensure that farm wastes containing biocides, or sterilising agents (e.g. bleach), or plants treated with certain herbicides, or animal waste after the use of certain drugs, do not enter the compost, If household waste (=“kitchen waste”) is used as an ingredient in compost, particular care needs to be taken that it is sorted carefully before composting to ensure that sources of heavy metals (e.g. batteries) and dangerous shards of broken glass are excluded.

When composting, it is important to try to optimise the Nitrogen:Carbon ratio. This usually means that a high Nitrogen-containing waste (e.g. chicken manure or other manures) should be combined with high Carbon wastes such as most crop residues, cardboard and paper. Potassium content can be enhanced by using the appropriate amount of wood ash, if this is available locally.

Examples of useful agricultural-waste-based compost ingredients include:

  • manure;
  • other biodegradable wastes from animal husbandry e.g. wood chippings, spoiled straw, wood or paper-based animal bedding;.
  • processing-waste e.g. rejected fruit or vegetable materials;
  • unsold crop;
  • wastes from polytunnel cultivation or other forms of intensive horticulture: There is specific guidance on mushroom farm substrate (e.g. http://www.fao.org/docrep/004/AB497E/ab497e07.htm#bm7.17 );
    • substrate from bags can be re-used to make new bags. Mycelium must be removed and substrate needs to be well pasteurized or converted into compost;
    • substrate bags can be converted into compost as follows:
      • break bags open and send plastic bags to be collected by municipality;
      • mix substrate with effective microorganism (EM) and sugar, and maintain humidity at 65-75 %;
      • place in used rice bags for a period of approximately 30 days or on the ground under the shade;
      • compost is then ready to be used in gardens, rice paddies or sold as organic fertilizer.

Organic matter can also be applied directly to the land, for example by spreading dredgings and plant material from ditches, or spoilt crops from stores onto the land. This may also include diluted waste milk.

FAO has published useful manuals for both small- and large-scale on-farm composting: http://www.fao.org/ORGANICAG/doc/On_farm_comp_methods.pdf ftp://ftp.fao.org/agl/agll/docs/lwdp2_e.pdf . Guidelines for composting agricultural wastes are also often available locally.

Manure and slurry management

The management of manures and slurrys is relevant to animal welfare, soils, nutrients, water and social (annoyance to neighbours) & human capital (health and safety).

The DEFRA Code of “Good Agricultural Practice” for farmers, growers and land managers “Protecting our Water, Soil and Air” has excellent sections on manure management. Other useful factsheets on manure and slurry management are available on: http://www.fecservices.co.uk/publications-slurry-waste , including The A to Z of farm waste - TN 31, Waste production - TN 32, The Venturi aerator - TN 33, Slurry treatment systems - TN 34, Slurry stirring - TN 35 Separation of slurries - TN 36, Composting of separated animal wastes - TN 48.