In addition to nitrogen, organic manures are valuable sources of other major plant nutrients (phosphate, potash, magnesium and sulphur) and organic matter. Further guidance on how to integrate manure and inorganic fertiliser use to best advantage, is provided in the following leaflets: Managing Livestock Manures Booklet 1 (revised 2001) - Making better use of livestock manures on arable land   Managing Livestock Manures Booklet 2 (revised 2001) - Making better use of livestock manures on grassland Managing Livestock Manures Booklet 3 (2001) - Spreading systems for slurries and solid manures These are available free of charge from ADAS Gleadthorpe Research Centre. Tel: +44 (0) 1623 844 331 More detailed advice on fertiliser use is published in: Fertiliser Recommendations for Agricultural and Horticultural Crops. DEFRA Reference Book 209, 7th Edition, 2000 (ISBN 0 11 243058 9). Available from Stationery Office bookshops or direct from The Stationery Office Tel: +44 (0) 870 600 5522 Organic manures should always be spread carefully with due regard for the environment. In particular, it is important to avoid water and air pollution. Manures should be applied at rates that supply no more than 250 kg total nitrogen per hectare per annum - this is a statutory requirement in Nitrate Vulnerable Zones (NVZs). Further details are available in: The Water Code (Code of Good Agricultural Practice for the Protection of Water) (PB 0587, revised 1998) The Air Code (Code of Good Agricultural Practice for the Protection of Air) (PB 0618, revised 1998) The Soil Code (Code of Good Agricultural Practice for the Protection of Soil) (PB 0617, revised 1998) Guidelines for Farmers in Nitrate Vulnerable Zones (PB 5505) Manure Planning in Nitrate Vulnerable Zones (PB 5504) These are available from DEFRA Publications, Tel: +44 (0) 8459 556000