|Hutchinson, Mark - UNIVERSITY OF MAINE|
Submitted to: Proceedings of the 2003 New England Vegetable and Berry Conference
Publication Type: Proceedings
Publication Acceptance Date: October 1, 2003
Publication Date: December 15, 2003
Citation: Griffin, T.S., Hutchinson, M. 2003. Mineralization of nitrogen from composts. Proceedings of the 2003 New England Vegetable and Berry Conference. Technical Abstract: Compost and other amendments play several roles in vegetable production systems. Most often, they are applied as "soil conditioners," because they contain stabilized carbon (C), but the prediction of nitrogen (N) release over time is also important. We conducted greenhouse and field experiments to evaluate N release for lettuce production, after application of raw or composted bean waste, fish waste, and fish waste mixed with sawdust. In the greenhouse, the application if immature compost supplied N in excess of lettuce demand, stimulating growth of two successive ryegrass crops after lettuce harvest. The use of fish waste, with or without sawdust, released N too quickly, before plant growth allowed for utilization. In the field, where lower application rates were used, compost N was released but the yield response was limited due to release of sufficient soil N. These experiments help refine N release estimates for composts, and demonstrate the importance of timing of N release.