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

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 (< 10 kg min-N ha(-1) soil) residual effect was recorded in 4-week post-harvest soil incubation. The performance of the products seemed predictable, although scarcely available N in the Sphagnum peat bedding limits the short-term availability of the granule total N content. By adjusting the amount and sort of amendment, fertilizer products designed for specific purposes can be produced from peat-bedded broiler manure. However, for pyrolyzed broiler manure, no N fertilizer effect can be expected. (C) 2020 Elsevier B.V. All rights reserved.