Fertilization of a mixed forage crop with fresh and composted chicken manure and NPK fertilizer: Effects on dry matter yield and soil and tissue N, P and K

An experiment was conducted for 3 yr to compare the effects of fertilization of mixed forage with fresh and composted chicken manure and inorganic NPK. Fertility amendments were applied each year at three N levels and an unfertilized treatment was included. The experiment was conducted in two hay fields near Truro, Nova Scotia. Dry matter yield and forage N, P and K contents are reported for the 1992 and 1993 seasons. The nutrient content of the amendments as well as the efficiency of P and K use are discussed. Soil Mehlich 3-extractable P and K and KCI-extractable N were measured at two depths in September 1993. By the final year of the experiment, compost amendments produced yields as high as the recommended rate of NPK fertilization at both sites on both harvest dates. Medium rates of compost application also resulted in tissue N levels as high as or higher than the equivalent NPK treatments. The medium rate of manure application was equivalent in yield and tissue N to the compost treatments at the Acadia site, but had slightly lower yields and tissue N content at the Pugwash site. Compost P and K were relatively inefficiently used by the forage; this resulted in increased levels of Mehlich 3-extractable P and K in the 0- to 15-cm layer of the compost-amended plots. It was concluded that fertilization with compost or inorganic NPK, supplying equal amounts of N, can result in comparable yields and quality of forage.