Soil organic carbon variability and sampling optimization in Montana dryland wheat fields.

Book Title: NA
Year Published: 2005
Month Published: NA
Author: Bricklemyer, R. S. ; Miller, P. R. ; Paustian, K. ; Keck, T. ; Nielsen, G. A. ; Antle, J. M.
Book Group Author: NA

Soil organic carbon varies spatially as a function of short-range and landscape scale variability and is influenced by natural soil variability, soil management, and the variability associated with soil sampling techniques. Accurate measurement methods and efficient sampling designs are needed to determine the net carbon change over time as a function of soil management changes. Soil organic carbon sampling variability in paired no-till and tilled dryland wheat fields in Montana was examined. Paired fields at two locations were chosen with soils, cropping system, landscape position, and climatic conditions similar within each pair. Sampling variability in soil organic carbon for the 0 to 10 cm depth was quantified among cores, microsites, and fields. Soil samples were analyzed for total and inorganic C, and particle-size distribution. Stratifying by soil-landscape association likely reduced soil organic carbon sample variability. Including percent clay as a covariant reduced soil organic carbon variance 40-fold (site level), however variance within sites (tillage effect) remained unchanged. Soil organic carbon was greater in no-till fields than tilled fields (P<0.01) at both Ft. Benton [18.2 Mg C ha-1 (8.1 t C ac-1) and 14.4 Mg C ha-1 (6.4 t C ac-1), respectively] and Simpson [8.8 Mg C ha-1 (3.9 t C ac-1) and 6.9 Mg C ha-1 (3.1 t C ac-1), respectively]. Variability within and between microsites was used to optimize the number of microsites per field and the number of cores per microsite for reliable soil organic carbon measurements. An optimal sampling design of four microsites by two cores or three microsites by three cores provided reliable detection of a tillage effect on soil organic carbon in fields sampled.

Pages: 42 - 51
Volume: 60
Number: 1
Journal: Journal of Soil and Water Conservation (Ankeny)
Journal ISO: NA
Organization: NA
Publisher: NA
ISSN: 0022-4561

agricultural soils, arid lands, carbon sequestration, clayfraction, cropping systems, dry farming, landscape, no-tillage, organiccarbon, particle size distribution, sampling, soil management, soilorganic matter, soil types, soil variability, wheat, Montana, USA,Triticum, Triticum aestivum, Poaceae, Cyperales, monocotyledons,angiosperms, Spermatophyta, plants, eukaryotes, Triticum, MountainStates of USA, Western States of USA, USA, North America, America,Developed Countries, OECD Countries, Great Plains States of USA, drylandfarming, no-tillage systems, organic matter in soil, samplingtechniques, United States of America, zero tillage, Field Crops (FF005)(New March 2000), Plant Production (FF100), Plant Cropping Systems(FF150), Soil Chemistry and Mineralogy (JJ200), Soil Morphology,Formation and Classification (JJ400), Soil Fertility (JJ600), SoilManagement (JJ900), Mathematics and Statistics (ZZ100)

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