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Maize and Prairie Root Contributions to Soil CO 2 Emissions in the Field
Author(s) -
Nichols Virginia,
Miguez Fernando,
Sauer Thomas,
Dietzel Ranae
Publication year - 2016
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2016.01.0048
Subject(s) - growing season , agronomy , perennial plant , biomass (ecology) , soil water , soil carbon , environmental science , biology , soil science
Increasing soil carbon content via agricultural practices not only enhances the production potential of the land, but also counteracts rising atmospheric CO 2 levels. When predicting production systems’ effects on soil carbon, quantifying CO 2 efflux derived from live roots is of particular importance as it is a through‐flux and does not signify depletion of soil carbon. This field study aimed to measure and compare soil CO 2 emissions derived from roots in annual and perennial agroecosystems. We used periodic 48‐hour shading over two growing seasons to estimate root growth‐derived CO 2 in continuously grown maize (CC) with grain and 50% stover harvested each year, unfertilized reconstructed tallgrass prairie (P), and the same prairie grown with spring nitrogen fertilization (PF), both which had biomass harvested post‐frost. In CC, P, and PF root‐derived CO 2 contributed to 28, 31, and 30% of each crop's respective growing season cumulative CO 2 emissions in 2012, and 19, 24, and 28% in 2013, respectively. Season‐cumulative root‐derived CO 2 was not proportional to end‐of‐season belowground biomass (BGB): P had nearly twice the BGB of PF, but their cumulative root‐derived fluxes were not significantly different in either year. A significant proportion of soil CO 2 emissions is derived from roots, making it a critical process to consider when comparing or modeling soil emissions of cropped or prairie soils. Using BGB alone may not be a useful proxy for estimating root contributions.