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Influence of irrigated agriculture on soil microbial diversity

Entry, J.A. and Mills, D.K. and Mathee, K. and Jayachandran, K. and Sojka, R.E. and Narasimhan, Giri (2008) Influence of irrigated agriculture on soil microbial diversity. Applied Soil Ecology. 40:146-154. 24 July 2008.

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Organic carbon (C), bacterial biomass and structural community diversity were measured in Southern Idaho soils with long term cropping histories. The soils tested were native sagebrush vegetation (NSB), irrigated moldboard plowed crops (IMP), irrigated conservation – chisel – tilled crops (ICT) and irrigated pasture systems (IP). Organic C concentration in soils decreased in the order NSB 0–5 cm > IP 0–30 cm = ICT 0–15 cm > IMP 0–30 cm > NSB 5–15 cm = NSB 15–30 cm. Active bacterial, fungal and microbial biomass correlated with soil C as measured by the Walkely Black method in positive curvilinear relationships (r2 = 0.93, 0.80 and 0.76, respectively). Amplicon length heterogeneity (LH-PCR) DNA profiling was used to access the eubacterial diversity in all soils and at all depths. The Shannon–Weaver diversity index was used to measure the differences using the combined data from three hypervariable domains of the eubacterial 16S rRNA genes. Diversity was greatest in NSB 15–30 cm soil and lowest in the IMP soil. With the exception of IMP with the lowest diversity index, the samples highest in C (NSB 0–5 cm, IP 0–30 cm, ICT 0–15 cm) reflected lower diversity indices. However, these indices were not significantly different from each other. ICT and IP increase soil C and to some extent increase diversity relative to IMP. Since soil bacteria respond quickly to environmental changes, monitoring microbial communities may be one way to assess the impact of agricultural practices such as irrigation and tillage regimes

Item Type: Article
NWISRL Publication Number: 1268
Subjects: Soil > Chemistry
Depositing User: Users 6 not found.
Date Deposited: 13 Aug 2008 20:46
Last Modified: 18 Oct 2016 15:48
Item ID: 1291