DIGESTATE AS A SUBSTITUTE OF FERTILIZERS IN THE CULTIVATION OF VIRGINIA FANPETALS.

Two types of digestate were used for the fertilization of Virginia fanpetals: from Virginia fanpetals (DVF) and from maize fermented with bovine slurry (DMS). A dose of DVF was determined according to the fertilization demand for K, and because of a low content of N in this waste, some treatments were designed with a supplementing dose of mineral nitrogen. In turn, the DMS was supplied to soil in an amount sufficient to meet N fertilization demand, but due to a small concentration of K in the waste, some treatments were designed with supplementing potassium nutrition. In both cases, the digestates were an exclusive source of phosphorus. Because of the low amount of N supplied to soil with DVF, the use of this element was 97 and 68%. The use of P from digestate by plants varied from 13 to 42%. Due to the lower amount of P brought in with DMS, Virginia fanpetals used more efficiently P from this type of waste. The use of K ranged from about 30 to 205%, which means that when the quantities of this element brought in with DMS were small, the plants absorbed very intensively the K contained in soil. The macronutrients from digestate were used by the plants at least as efficiently as the ones originating from mineral fertilizers. Therefore DVF or DMS is suitable for the fertilization of Virginia fanpetals. [ABSTRACT FROM AUTHOR]