Low cost aerobic stabilisation of poultry layer Manure

摘要

A prototype, low-rate ventilation system, for the in-situ treatment of deep pit layer manure has been developed using small fans and air ducted beneath the accumulating manure via perforated plastic pipe. The system has proved capable of generatinghigh dry matter poultry manure, at reasonable cost. Based on the study findings, the costs might be contained within c. 3.60 pound per tonne of manure, or 14 p per bird, by using low cost night-time electricity. These costs might be at least partially recovered by the observed, improved utilisation of manure nitrogen (N) in crop production. The drying process, once effectively established, appears to significantly reduce ammonia emissions during the production cycle. The process results in an apparentlystabilised manure product, with a consistently lower ammonium-N (NH_4-N) content and increased uric acid-N content, compared with untreated layer manure. Nitrogen in the "stabilised" manure appears to be utilised by crops consistently more efficiently than untreated layer manure N. Manure uric acid + NH_4-N (UAN) or NH_4-N content are the currently accepted standards for estimating the N supply potential of layer manure following land application. However, field experiments using the differentially treated manure, suggested that uric acid content, on its own, may provide a more reliable estimation.