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Irrigation increases inorganic carbon in agricultural soils

El Carbono Inorgánico se Incrementa en Suelos Agrícolas con irrigación

Entry, James A. and Sojka, R.E. and Shewmaker, Glenn E. (2004) Irrigation increases inorganic carbon in agricultural soils. Environmental Management. 33(Supplement 1):S309-S317.

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Abstract

Inorganic C reactions are among the most important
chemical reactions that occur in irrigated soils and
may contribute to the total amount of C sequestered in those
soils. Because CO2 can escape from soils to the atmosphere
or return to precipitate carbonate minerals, soils are open systems
with regard to inorganic C. We measured inorganic and
organic C stored in southern Idaho soils having long-term
land-use histories that supported native sagebrush vegetation
(NSB), irrigated moldboard plowed crops (IMP), irrigated conservation
(chisel) tilled crops (ICT), and irrigated pasture systems
(IP). Inorganic C and total C (inorganic + organic C) in
soil decreased in the order IMP>ICT>IP>NSB. We use our
findings to estimate that amount of possible inorganic and
total C sequestration if irrigated agriculture were expanded by
10%. If irrigated agricultural land were expanded by 10%
worldwide and NSB were converted to IMP, a possible 1.60
x 108 Mg inorganic C (2.78% of the total C emitted in the
next 30 years) could be sequestered in soil. If irrigated agricultural
land were expanded by 10% worldwide and NSB were
converted to ICT, a possible 1.10 x 109 Mg inorganic C
(1.87% of the total C emitted in the next 30 years) could be
sequestered in soil. If irrigated agricultural land were expanded
worldwide and NSB were converted to IP, a possible gain of
2.6 x 108 Mg inorganic C (0.04% of the total C emitted in the
next 30 years) could be sequestered in soils. Inorganic C sequestered
from land-use changes have little potential to make
a significant impact on the concentration of atmospheric CO2.
However, when coupled with organic C and altering land use
to produce crops on high-output irrigated agriculture while
selected less productive rain-fed agricultural land was returned
to temperate forest or native grassland, there could be
reductions in atmospheric CO2.

Item Type: Article
NWISRL Publication Number: 1131
Subjects: Soil > Chemistry
Mass Import - autoclassified (may be erroneous)
Depositing User: Dan Stieneke
Date Deposited: 20 Nov 2010 21:58
Last Modified: 25 Oct 2016 17:55
Item ID: 1212
URI: https://eprints.nwisrl.ars.usda.gov/id/eprint/1212