Soil Good soil management is the key to plant and livestock nutrition in organic farming. The wider value of good quality soils and appropriate soil management to our environment is at last starting to receive greater recognition and attention. Understanding the potential and limitations of the soil on your farm, how farming operations affect its properties and how to maintain or build and utilise fertility should be the primary consideration for all organic farmers. The soil beneath our feet is something most of us take for granted. It is, however, a precious resource that largely governs agricultural sustainability and environmental quality - both locally and globally. Simpson (1983) sums up soil thus: "Soil is the basis of agriculture. It is the main raw material from which food is produced. Unlike the raw materials of most industries it can, with some supplementation, be used again year after year, century after century." Soil conditions govern crop production and crop quality, and in turn influence both animal and human health. This was recognised by the founders of the modern organic movement in the mid-20th century. These pioneers recognised that in order to deliver health, farming systems need to build and conserve natural soil fertility through the development of humus. In order to achieve this farming practice needs to observe and emulate natural processes of death, decay and regeneration. It is these observations that underpin the principles and practices of organic farming today. Despite recognition by organic farmers and growers that soil health is at the heart of successful organic production, best soil management practice on farm is still the exception rather than the rule. It is certain that as we learn more about this complex and fascinating subject, so to will we make developments in agricultural practice that best serve to protect and enhance the health of our soils. Compost Good compost is a source of stabilised nutrients generated as a result of microbial decomposition of organic matter to produce humus. The end product of an effective composting process is an ideal long-term source of fertility, to build the soils existing bank. The stability of the compost means that losses through run off or leaching are much lower than would be the case with equivalent applications of fresh manure or slurry. Apart from being environmentally beneficial this also means that more nutrients are retained in the soil for use by subsequent crops. Furthermore, when undertaken effectively, the composting process removes pests, pathogens, weeds and toxins that may be present in fresh or stacked manure. Composts have also been shown to contain beneficial micro-organisms that help to protect crops from disease causing organisms. Compost is a result of a biological process. Initially a range of organisms degrade large, complex pieces of organic matter to simple molecules. During this phase the organisms generate heat and the temperature in the compost heap rises significantly from ambient temperature to approximately 60C in about a week. If kept above 55C and below 70C for three days, the high temperature will kill pathogens. After this initial phase lasting about 14 days the temperature of the heap will start to drop as all the organic matter becomes broken down. In the second phase new groups of organisms colonise the heap, feeding on the heat-loving organisms. It is during this phase that long chain humic acid substances develop to bind to clay particles in the heap to form the clay-humus crumb. This build up phase takes a further four weeks or so. A number of key things are required to produce good compost: Selection of appropriate ingredients to give the right balance of carbon to nitrogen The more diverse the ingredients the more diverse the range of nutrients that are likely to be held in the final compost Management – simply piling manure in a field and leaving it for four months is not composting! Oxygen throughout the heap – if the heap becomes anearobic (without oxygen) beneficial organsims will die and toxin-producing anearobic organisms will begin to colonise the heap Water – not too much to drive out oxygen but enough to support microbial activity. Information resources Compost: the microbial way Composts, plant raising media, soil inoculants and mulches for use in organic production Green waste compost and soil Association standards Soil: the importance and protection of a living soil. Access these documents below. If not visible, make sure you have registered and logged in as a producer services member. Still not visible? Try our full library. Or contact us to get a copy. » Compost - the microbial way 02/14/2007 » Green waste compost and Soil Association standards 08/20/2007 » Technical Factsheet and Briefing Paper Order Form - June 2007 08/17/2007 » Technical guides from the food and farming department (Summer 2007) 08/17/2007 Technical guides Soil Management on Organic Farms. See our full list of technical guides to order this and other technical guides from our online shop. Soil testing services ADAS Laboratories Woodthorne, Wergs Road, Wolverhampton WV6 8TQ T: 01902 693229 F: 01902 746183 enquiries@adas.co.uk www.adas.co.uk Anglian Soil Analysis Ltd One Way Street, Sutterton, Boston, Lincolnshire PE20 2JQ T: 01205 460590 F: 01205 460814 E: asa@angliansoil.co.uk Brookside Laboratories Robin Boom, 2 Thorn Cottages, East Sutton Road, Headcorn, Kent TN27 9PR T: 01622 891741 E: robin@boomr.freeserve.co.uk Eastern Growers Laboratories Brecklands Estate, Downham Road, Swaffham, Norfolk PE37 7QE T/F: 01760 724499 E: egl@sasltd.co.uk www.wasltd.co.uk Ground Level Nutrition Kingstone Farmhouse, Kingstone, Nr Ilminster, Somerset TA19 0NS T: 01460 54157 F: 01460 52627 E: jo.scamell@btinternet.com Independent Soil Services Saddlebow House, Poplar Avenue, Saddlebow, Kings' Lynn, Norfolk PE34 3AA T: 01553 772525 F: 01553 768472 E: independentsoils@farmline.com www.independentsoils.co.uk National Institute of Agricultural Botany Huntingdon Road, Cambridge CB3 0LE T: 01223 342200 F: 01223 342327 E: labtest@niab.com www.niab.com Organic Crop Management Ltd Burleyheyes, Arley Road, Appleton Road, Appleton Thorn, Warrington, Cheshire WA4 4RS T: 01565 777555 F: 01565 777468 Scottish Agriculture College West Mains Road, Edinburgh, EH9 3JG T: 0131 622 1303 www.sac.ac.uk Soil-Tec Analytical Systems PO Box 61, Sleaford, Lincolnshire NG34 9NL T: 01529 460672 F: 01529 460989 Waterfall & O'Brien Ltd 138 Forest Road, Fishponds, Bristol BS16 3SN T: 0117 958 3448 F: 0117 958 6776 E: sales@waterfallobrien.co.uk www.waterfallobrien.co.uk