<human>:  Why do they use manure in organic and Biodynamic agriculture?
<bot>: Manure is used in organic and biodynamic agriculture because it is a natural fertilizer. In organic agriculture, manure is used as a natural fertilizer. In biodynamic agriculture, manure is used as a natural fertilizer, but it is also used to make preparations called 'preparations'. These preparations are made from the products of the composting process. These preparations are used to enhance the soil, to increase the health of the plants, and to strengthen the immune system of the plants.