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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #168201
Title: IRRIGATED AGRICULTURE AND TILLAGE PRACTICES IMPACT MICROBIAL COMMUNITY STRUCTURE

Author
item MILLS, DEETTA - FLORIDA INT'L UNIVERSITY
item Entry, James
item MATHEE, KALAI - FLORIDA INT'L UNIVERSITY
item NARASIMHAN, GIRI - FLORIDA INT'L UNIVERSITY
item JAYACHANDRAN, KRISH - FLORIDA INT'L UNIVERSITY
item Sojka, Robert
item Busscher, Warren

Submitted to: International Soil Tillage Research Organization Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 7/20/2003
Publication Date: 7/20/2003
Citation: Mills, D., Entry, J.A., Mathee, K., Narasimhan, G., Jayachandran, K., Sojka, R.E., Busscher, W.J. 2003. Irrigated agriculture and tillage practices impact microbial community structure. Proceedings of the 16th Triennial Conference of International Soil Tillage Research Organization: Soil Management for Sustainability. p. 749-754.

Interpretive Summary: Intensively managed crop or pastureland has potential for C gain through the use of improved grazing regimes, fertilization practices and irrigation management. Organic C and microbial structural diversity present in Southern Idaho soils having long term cropping histories was measured. The sites sampled were native sagebrush vegetation (NSB); irrigated moldboard plowed crops (IMP), irrigated conservation -chisel- tilled crops (ICT) and irrigated pasture systems (IP). Using the profiling data from four hypervariable regions of the 16S rRNA (V1, V1+V2, V3 and V9), it was shown that NSB communities differed in bacterial richness within the top 30 cm when compared to the irrigated agricultural soils. Between the agricultural management systems the bacterial richness of conservation-tilled soils was greater than IMP but less than IP. Since ICT and IP increase C sequestration and appear to support higher eubacterial diversity in soils compared to IMP, producers can use these management practices on their lands to sequester organic C, improve soil microbial diversity and enhance soil biological processes.

Technical Abstract: Intensively managed crop or pastureland has potential for C gain through the use of improved grazing regimes, fertilization practices and irrigation management. Soil microbial diversity is important because it is often regarded as an index of soil health. Organic C and microbial structural diversity present in Southern Idaho soils having long term cropping histories was measured. The sites sampled were native sagebrush vegetation (NSB); irrigated moldboard plowed crops (IMP), irrigated conservation -chisel- tilled crops (ICT) and irrigated pasture systems (IP). Using the profiling data from four hypervariable regions of the 16S rRNA (V1, V1+V2, V3 and V9), it was shown that NSB communities differed in bacterial richness within the top 30 cm when compared to the irrigated agricultural soils. Between the agricultural management systems (in the top 30 cm) the bacterial richness of conservation-tilled soils was greater than IMP but less than IP. Soil C concentrations also correlated with eubacterial diversity indices for the four variable regions (correlation coefficients = 0.91, 0.92, 0.68, 0.70, respectively), evenness indices (correlation coefficients = 0.72, 0.68, 0.93, 0.80, respectively) and the active bacterial biomass (correlation coefficients = 0.75, 0.75, 0.79, 0.79 respectively). Since ICT and IP increase C sequestration and appear to support higher eubacterial diversity in soils compared to IMP, producers can use these management practices on their lands to sequester organic C, improve soil microbial diversity and enhance soil biological processes.