DEVELOPING A SLOW-RELEASE NITROGEN-FERTILIZER FROM ORGANIC SOURCES .2. USING POULTRY FEATHERS

The structure of feather keratin protein was modified in attempts to d evelop a slow-release N fertilizer of 12 weeks duration or longer by s team hydrolysis to break disulfide bonds, enzymatic hydrolysis with Ba cillus licheniformis (Weigmann) to break polypeptide bonds, and steam hydrolysis (autoclaving) to hasten mineralization followed by crosslin king of the protein by a formaldehyde reaction to control the increase d rate of mineralization. Release of N in potting substrate within elu tion columns from ground, but otherwise untreated, raw feathers occurr ed mainly during the first 5 weeks with a much smaller release occurri ng from weeks 8 to 12. Steam hydrolysis resulted in an increase of N d uring the first 5 weeks and a decrease during weeks 8 to 11. Cumulativ e N release over 11 weeks increased from 12% in raw feathers to 52% fo r feathers steam hydrolyzed for 90 minutes. This favored an immediatel y available fertilizer but not a slow-release fertilizer. Microbial hy drolysis with B. licheniformis resulted in a modest reduction of N rel ease during the first 5 weeks and a small increase during weeks 8 to 1 1. Both shifts, while not desirable for an immediately available ferti lizer, enhanced the slow-release fertilizer potential of feathers but not sufficiently to result in a useful product, Steam hydrolyzed feath ers cross-linked with quantities of formaldehyde equal to 5% and 10% o f the feather weight released less N during the first 5 weeks, more du ring weeks 6 and 7, and less during weeks 9 to 12 compared to raw feat hers. The first two shifts were favorable for a slow-release fertilize r while the third was not.