Title: Long‐term nitrous oxide fluxes in annual and perennial agricultural and unmanaged ecosystems in the upper Midwest USA

Abstract

Abstract Differences in soil nitrous oxide (N ₂ O) fluxes among ecosystems are often difficult to evaluate and predict due to high spatial and temporal variabilities and few direct experimental comparisons. For 20 years, we measured N ₂ O fluxes in 11 ecosystems in southwest Michigan USA : four annual grain crops (corn–soybean–wheat rotations) managed with conventional, no‐till, reduced input, or biologically based/organic inputs; three perennial crops (alfalfa, poplar, and conifers); and four unmanaged ecosystems of different successional age including mature forest. Average N ₂ O emissions were higher from annual grain and N‐fixing cropping systems than from nonleguminous perennial cropping systems and were low across unmanaged ecosystems. Among annual cropping systems full‐rotation fluxes were indistinguishable from one another but rotation phase mattered. For example, those systems with cover crops and reduced fertilizer N emitted more N ₂ O during the corn and soybean phases, but during the wheat phase fluxes were ~40% lower. Likewise, no‐till did not differ from conventional tillage over the entire rotation but reduced emissions ~20% in the wheat phase and increased emissions 30–80% in the corn and soybean phases. Greenhouse gas intensity for the annual crops (flux per unit yield) was lowest for soybeans produced undermore » conventional management, while for the 11 other crop × management combinations intensities were similar to one another. Among the fertilized systems, emissions ranged from 0.30 to 1.33 kg N ₂ O‐N ha ⁻¹  yr ⁻¹ and were best predicted by IPCC Tier 1 and Δ EF emission factor approaches. Annual cumulative fluxes from perennial systems were best explained by soil pools ( r ²  = 0.72) but not so for annual crops, where management differences overrode simple correlations. Daily soil N ₂ O emissions were poorly predicted by any measured variables. Overall, long‐term measurements reveal lower fluxes in nonlegume perennial vegetation and, for conservatively fertilized annual crops, the overriding influence of rotation phase on annual fluxes.« less

Authors:

Gelfand, Ilya  ^[1];

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Shcherbak, Iurii ^[2]; Millar, Neville ^[1]; Kravchenko, Alexandra N. ^[3]; Robertson, G. Philip ^[4]

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+ Show Author Affiliations

1. W.K. Kellogg Biological Station Michigan State University Hickory Corners MI 49060 USA, Great Lakes Bioenergy Research Center Michigan State University East Lansing MI 48824 USA
2. W.K. Kellogg Biological Station Michigan State University Hickory Corners MI 49060 USA, Department of Plant, Soil, and Microbial Sciences Michigan State University East Lansing MI 48824 USA
3. Department of Plant, Soil, and Microbial Sciences Michigan State University East Lansing MI 48824 USA
4. W.K. Kellogg Biological Station Michigan State University Hickory Corners MI 49060 USA, Great Lakes Bioenergy Research Center Michigan State University East Lansing MI 48824 USA, Department of Plant, Soil, and Microbial Sciences Michigan State University East Lansing MI 48824 USA

Publication Date:

Thu Aug 11 00:00:00 EDT 2016

Research Org.:

Univ. of Wisconsin, Madison, WI (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER)

OSTI Identifier:

1290321

Alternate Identifier(s):

OSTI ID: 1290323; OSTI ID: 1427682

Grant/Contract Number:  

DE‐FC02‐07ER64494; FC02-07ER64494

Resource Type:

Published Article

Journal Name:

Global Change Biology

Additional Journal Information:

Journal Name: Global Change Biology Journal Volume: 22 Journal Issue: 11; Journal ID: ISSN 1354-1013

Publisher:

Wiley-Blackwell

Country of Publication:

United Kingdom

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; 59 BASIC BIOLOGICAL SCIENCES; corn; cover crops; crop type; forest; nitrogen fertilizer; no-till; rotation phase; soybean; succession; wheat