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Nitrous Oxide Fluxes in Fertilized Pinus taeda L. Plantations across a Gradient of Soil Drainage Classes
Author(s) -
Shrestha Raj K.,
Strahm Brian D.,
Sucre Eric B.
Publication year - 2014
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2014.03.0109
Subject(s) - fertilizer , nitrous oxide , soil water , human fertilization , drainage , environmental science , zoology , urea , agronomy , hydrology (agriculture) , chemistry , ecology , biology , soil science , geology , organic chemistry , geotechnical engineering
The effect of fertilizer management on nitrous oxide (N 2 O) fluxes in agricultural ecosystems is well documented; however, our knowledge of these effects in managed forests is minimal. We established a comprehensive research study to address this knowledge gap across a range of soil drainage classes (poorly, moderately, and well drained) common in southern pine plantation management. Fertilizer treatments in each drainage class comprised of control (no fertilizer), urea + phosphorus (P), and P‐coated urea fertilizer (CUF). Fertilization (168 kg N ha −1 ) occurred independently during the spring, summer, and fall to assess the effects of application timing. Nitrous oxide sampling, using vented static chambers, started immediately after seasonal fertilizer application and was performed every 6 wk for more than 1 yr. Time‐integrated net annual N 2 O emissions increased with urea (1.15 kg N 2 O–N ha −1 ) and CUF (0.88 kg N 2 O–N ha −1 ) application compared with unfertilized control (0.22 kg N 2 O–N ha −1 ). Mean annual N 2 O flux was significantly increased with fall fertilization (1.17 kg N 2 O–N ha −1 ) relative to spring (0.73 kg N 2 O–N ha −1 ) or summer (0.33 kg N 2 O–N ha −1 ). Similarly, average annual N 2 O flux was higher in poorly drained soils (1.40 kg N 2 O–N ha −1 ) than in moderately drained (0.46 kg N 2 O–N ha −1 ) and well‐drained soils (0.39 kg N 2 O–N ha −1 ). This study suggests that N 2 O emissions after fertilization can be minimized by avoiding fall fertilization and poorly drained soils and by selecting enhanced‐efficiency N fertilizers over urea.