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Management of irrigated agriculture to increase carbon storage

Sojka, R.E. and Entry, J.A. and Shewmaker, G.E. and Fuhrmann, J.J. (2007) Management of irrigated agriculture to increase carbon storage. pp. 189-202. In: Currie, L.D. and Yates, L.J. (eds.) Proceedings of the Fertilizer & Lime Research Centre Workshop. Designing Sustainable Farms: Critical Aspects of Soil and Water Management. New Zealand-Palmerston North, 2007/02/08-09.

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Abstract

Fossil fuel burning at the present rate, will double atmospheric carbon dioxide (CO 2 ) in this
century, raising air temperature 1.5 to 5 °C. Sequestering carbon (C) in soil can reduce
atmospheric CO2 concentration. We measured inorganic and organic C in southern Idaho
soils having long term land use histories of native sagebrush vegetation (NSB), irrigated
moldboard plowed crops (IMP), irrigated conservation- (chisel) tilled crops (ICT) and
irrigated pasture systems (IP). Soil Organic C (SOC) decreased in the order
IP>ICT>NSB>IMP. We used our findings to estimate potential amounts of organic C
sequestered if irrigated agriculture expanded. If irrigated agricultural land was expanded
by10°/0 worldwide and NSB was converted to ICT, 2.5 x 10 9 Mg organic C (4.38 °A of the
total C emitted in the next 30 yr) could potentially be sequestered in soil. If irrigated
agricultural land were expanded by 10% worldwide and NSB were converted to IP, a possible
9.3 x 109 Mg organic C (16.32 % of the total C emitted in the next 30 yr) could be sequestered
in soil. Irrigated agriculture produces twice the yield compared to non-irrigated land.
Irrigation increases soil C relative to native semi arid or arid sites. Since irrigated agriculture
produces higher yields, less land area needs to be put into production compared to rainfed
agriculture. Altering land use to produce crops on high output irrigated agriculture, while
returning less-productive rainfed agricultural land to temperate forest or native grassland,
could further reduce atmospheric CO2 . Inorganic carbon increases with irrigation were less
consistent and much smaller than SOC. Irrigating these soils also increased microbial
biomass and changed microbial diversity.

Item Type: Conference or Workshop Item (Paper)
NWISRL Publication Number: 1225
Subjects: Mass Import - unclassified
Depositing User: Dan Stieneke
Date Deposited: 20 Nov 2010 21:55
Last Modified: 31 Oct 2016 17:12
Item ID: 857
URI: https://eprints.nwisrl.ars.usda.gov/id/eprint/857