Influence of irrigated agriculture on soil carbon and microbial community structure

La Influencia de Agricultura de Irrigación en el Carbono del Suelo y la Estructura de la Comunidad Microbiana

Entry, James A. and Fuhrmann, Jeffry J. and Sojka, R.E. and Shewmaker, Glen A. (2004) Influence of irrigated agriculture on soil carbon and microbial community structure. Environmental Management. 33(Supplement 1):S363-S373.

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Abstract

Increasing the amount of carbon (C) in soils is
one method to reduce the concentration of carbon dioxide
(CO2) in the atmosphere. We measured organic C stored in
southern Idaho soils having long-term cropping histories that
supported native sagebrush vegetation (NSB), irrigated moldboard
plowed crops (IMP), irrigated conservation-chisel-tilled
crops (ICT), and irrigated pasture systems (IP). The CO 2 emitted
as a result of fertilizer production, farm operations, and
CO2 lost via dissolved carbonate in irrigation water, over a
30-year period, was estimated and used to calculate net C
fixation. Organic C in ecosystems decreased in the order
IP>ICT>IMP> NSB. In February 2001, active fungal, bacterial,
and microbial biomass was greater in IP soils than all
other soils. Active fungal, bacterial, and microbial biomass
was least in ICT soils at the 15-30-cm depth than all other
soils. In August 2001, active bacterial biomass was greater in
IMP soils than IP, ICT, and NSB soils. Active fungal biomass
was greater in IP soils than all other soils. Whole-soil fatty acid
profiles differed among management regimes and sampling
dates and, to a lesser extent, with soil depth. FAME profiles
from the NSB soils were distinct from the agricultural treatments
and contained greater amounts of total fatty acids than
the other treatments. The IMP and ICT soils yielded fatty acid
profiles that were similar to each other, although those at the
15-30-cm depth were distinct from all other treatment-depth
combinations. The IP FAME profiles suggest that arbuscular
mycorrhizal fungi are more common in these soils than soils
from the other treatments. Differences in carbon substrate
utilization patterns (BIOLOG) among treatments were more
variable and less pronounced that FAME results. In general,
irrigated arid soils can both increase C storage while increasing
microbial biomass and changing microbial diversity.

Item Type:	Article
NWISRL Publication Number:	1132
Subjects:	Soil > Chemistry Mass Import - autoclassified (may be erroneous)
Depositing User:	Dan Stieneke
Date Deposited:	07 Mar 2008 18:24
Last Modified:	25 Oct 2016 17:54
Item ID:	1213
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/1213