In:
Soil Science Society of America Journal, Wiley, Vol. 74, No. 5 ( 2010-09), p. 1623-1634
Abstract:
Legume rotations and animal manures can reduce synthetic fertilizer use in row crops, but only long‐term experiments can elucidate effects of multiple legume rotations and decades of manure additions on soil gas emissions. In 2006 and 2007, we measured soil‐atmosphere fluxes of N 2 O, NH 3 , and CO 2 in maize ( Zea mays L.) crops within a replicated experiment comparing continuous maize to maize–alfalfa ( Medicago sativa L.) rotations initiated in 1969. In both systems, comparisons of synthetic fertilizer N and manure N were initiated in 1990. With synthetic fertilizer as the main N source, mean CO 2 –C fluxes (from March 31st to October18th) were lower from continuous maize (CC, 512 ± 132 g m −2 growing season −1 ) than from maize following alfalfa (CA, 691 ± 91 g m −2 growing season −1 ). In contrast, with manure as the main N source, mean soil CO 2 –C fluxes from CC (943 ± 111 g m −2 growing season −1 ) were greater than from CA (682 ± 21g m −2 growing season −1 ). Soil CO 2 –C emissions correlated with long‐term inputs of manure. Synthetically fertilized continuous maize had lower N 2 O‐N fluxes (0.36 ± 0.26 g m −2 growing season −1 ) than other treatments (0.55–0.58 g m −2 growing season −1 ). Nitrous oxide‐N fluxes were not correlated with current N inputs or soil nitrate concentrations, suggesting that long‐term treatment effects (e.g., on soil structure, labile C, or microbial communities) contribute to contemporary N 2 O variation. Elevated NH 3 fluxes ( 〉 5 mg NH 3 –N m −2 h −1 ) followed manure applications, but within weeks there were no significant treatment differences in NH 3 fluxes. These results suggest that short‐term or single‐factor studies may not capture important interactions among crop rotations and N sources affecting greenhouse gas emissions from agricultural soils.
Type of Medium:
Online Resource
ISSN:
0361-5995
,
1435-0661
DOI:
10.2136/sssaj2009.0446
Language:
English
Publisher:
Wiley
Publication Date:
2010
detail.hit.zdb_id:
241415-6
detail.hit.zdb_id:
2239747-4
detail.hit.zdb_id:
196788-5
detail.hit.zdb_id:
1481691-X
SSG:
13
SSG:
21
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