Granulated broiler manure based organic fertilizers as sources of plant available nitrogen

Abstract Refining broiler manure to nitrogen (N) fertilizer products of consistent quality and balanced nutrient content could promote agronomic exploitation of this nutrient rich resource. For ensuring the effectiveness and sustainable use of such products, their plant available N supply needs to be known. In this study, the N fertilizer value of peat bedded broiler manure as pure granules (BM) and feather meal amended granules (BM+FM) was assessed in a pot experiment with ryegrass and field experiment with onion. The pot experiment examined also the performance of pure feather meal (FM) and slow pyrolyzed broiler manure (PyrBM). As measured by mineral N fertilizer equivalence, 68%, 45%–50%, 35%–43%, and 3% of the total N in FM, BM+FM, BM and PyrBM, respectively, was available to plants during the first growing season in favorable conditions. A minor (