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Repeated Fertilization Effects on Nitrogen Fluxes Measured by Sequential Coring
Author(s) -
Whynot Tim W.,
Weetman Gordon F.
Publication year - 1991
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1991.03615995005500040035x
Subject(s) - mineralization (soil science) , coring , human fertilization , pinus contorta , fertilizer , nitrogen cycle , environmental science , nitrogen , zoology , chemistry , agronomy , soil science , ecology , environmental chemistry , soil water , biology , mechanical engineering , drilling , organic chemistry , engineering
Improving site quality is an important goal of optimum‐nutrition trials where fertilizer is applied repeatedly to a site. Site quality is often measured by the rate of N mineralization, but commonly used agronomic methods for assessing N availability are often not suitable for forestry use; therefore, the merits of other methods need to be examined. To determine if four repeated N fertilizations at four rates in a young lodgepole pine ( Pinus contorta [Dougl.] var. latifolia ) stand had changed soil N‐mineralization rates, and to compare field and laboratory techniques for measuring N mineralization, the results of in situ sequential coring and anaerobic incubation were compared. Estimates of gross potential mineralizable N (laboratory‐incubated mineral N concentration) were consistent with field estimates, while net potential mineralization N (gross mineralizable N minus initial N concentration) estimates were not. While the data suggested increases in N fluxes, repeated N and P+K fertilization did not produce statistically significant increases ( P > 0.05) in either N mineralization or uptake. Because sequential coring results in minimal soil disturbance and is sensitive to environmental processes, it is useful for evaluating other techniques for measuring N mineralization in forests, but requires intensive spatial and temporal sampling, which will limit its use. Because of variable flux rates following fertilization, mineralization should be measured two or more years following fertilization to determine if a significant change in site quality has occurred.