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ARS Home » Northeast Area » Orono, Maine » New England Plant, Soil and Water Research Laboratory » Research » Publications at this Location » Publication #198445
Title: IMPACTS OF SOIL AMENDMENT HISTORY ON NITROGEN AVAILABILITY FROM MANURE AND FERTILIZER

Author
item MALLORY, ELLEN - UNIV OF MAINE
item Griffin, Timothy

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/2007
Publication Date: 5/16/2007
Citation: Mallory, E., Griffin, T.S. 2007. Impacts of soil amendment history on nitrogen availability from manure and fertilizer. Soil Science Society of America Journal. Vol 71:964-973

Interpretive Summary: Long-term additions of organic material like animal manure not only increase stocks of potentially available nitrogen (N) in the soil, but also bring about changes in soil characteristics that can influence the N cycle. We conducted a laboratory experiment to explore how soil amendment history affects the transformation and availability of recently added N from manure or fertilizer. Soil was collected from a 13-year cropping systems experiment with both amended and unamended plots. Nitrogen source treatments were: Control (no added N), N Fertilizer, a net mineralizing manure (MManure), and a net immobilizing manure (IManure). Soil inorganic N concentrations were monitored over a 282 day period. When no N was added, net release of N in the historically amended soil was twice that in the historically nonamended soil, mostly due to differences in the size of the total N pool in the soil. When N sources were added, net N release and the estimated size of soil N pools were affected by both soil amendment history and N source. Historically amended soil reduced the availability of recently added N relative to the nonamended soil. Future work modeling N availability should consider soil amendment history not only for its effects on soil N supply capacity, but also for its effects on the availability of recently added N sources.

Technical Abstract: Repeated, long-term additions of organic material not only increase stocks of mineralizable soil nitrogen (N), but also bring about changes in soil characteristics that influence N dynamics. We conducted an aerobic incubation to explore how soil amendment history affects the transformation and availability of recently added N. Soil was collected from plots under contrasting amended and nonamended soil management systems in a 13-year cropping systems experiment. Nitrogen source treatments were: Control (no added N), NH4+ Fertilizer, a net mineralizing manure (MManure), and a net immobilizing manure (IManure). Soil NH4 and NO3 concentrations were monitored over 282 d. A two-pool, first-order model with fixed rate parameters was fitted to the NO3 accumulation data. When no N was added, net mineralization in the historically amended soil was twice that in the historically nonamended soil, mostly due to differences in soil total N stocks. When N sources were added, NH4 consumption, net N mineralization, and estimated N pools were affected by both soil amendment history and N source, with a significant interaction between the two factors. Historically amended soil reduced the availability of recently added N relative to the nonamended soil. This reduction occurred in the active pool (N1) for MManure and in the slow pool (N2) for Fertilizer. It appeared to be related to the timing of C availability. Future work modeling N availability should consider soil amendment history not only for its effects on soil N supply capacity, but also for its effects on the availability of recently added N sources.