Biodynamic field spray preparations 500, 500 & 508 is a term used collectively for those three (of nine) Biodynamic preparations which are sprayed directly on the vineyard (or farm), namely Horn manure 500, Horn silica 501, and Equisetum arvense 508 (Common horsetail). Of the other six, five (yarrow 502, chamomile 503, stinging nettle 504, oak bark 505, dandelion 506) are inserted into the Biodynamic compost pile, and one (valerian 507) is poured into and/or over the pile once completed.