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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #103303
Title: EVALUATION OF PLANT ORGANIC MATTER VIA CARBON ANALYSIS

Author
item Grings, Elaine
item Haferkamp, Marshall
item Heitschmidt, Rodney

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/1999
Publication Date: N/A
Citation: GRINGS, E.E., HAFERKAMP, M.R., HEITSCHMIDT, R.K. EVALUATION OF PLANT ORGANIC MATTER VIA CARBON ANALYSIS. AGRONOMY ABSTRACTS. 1999. p. 152.

Interpretive Summary: Validation of the use of C analysis to estimate organic matter (OM) content of herbage samples was conducted. Samples collected over two years were analyzed for C using a C-N analyzer and for OM by determining the weight lost after ashing in a muffle furnace at 525 deg C for 10 h. Samples (n=196) were collected from six pastures seeded to one of three species (Agropyron spp. 'Hycrest', Pascopyrum smithii 'Rosana', and Elytrigia intermedia 'Luna'). Forage samples were collected on two dates in Year 1 and on three dates in Year 2 by clipping to the ground. Forages were dried at 60 deg C for 48 h, ground to pass a 1-mm mesh screen in a Wiley mill, and analyzed for OM. A subsample of ground forage was reground in a roller mill for 24 h and used for C determination. OM:C averaged 2.03 +/- .005. The ratio was not affected by year, date, or pasture species (P > 0.10). It appears that C analysis can be used to estimate OM. Samples containing a large amount of lipid had different ratios indicating the correction factor should be validated for plant type. Atemesia tridentata had a ratio of 1.84 and Carthamus tinctorius seeds had a ratio of 1.64.

Technical Abstract: Validation of the use of C analysis to estimate organic matter (OM) content of herbage samples was conducted. Samples collected over two years were analyzed for C using a C-N analyzer and for OM by determining the weight lost after ashing in a muffle furnace at 525 deg C for 10 h. Samples (n=196) were collected from six pastures seeded to one of three species (Agropyron spp. 'Hycrest', Pascopyrum smithii 'Rosana', and Elytrigia intermedia 'Luna'). Forage samples were collected on two dates in Year 1 and on three dates in Year 2 by clipping to the ground. Forages were dried at 60 deg C for 48 h, ground to pass a 1-mm mesh screen in a Wiley mill, and analyzed for OM. A subsample of ground forage was reground in a roller mill for 24 h and used for C determination. OM:C averaged 2.03 +/- .005. The ratio was not affected by year, date, or pasture species (P > 0.10). It appears that C analysis can be used to estimate OM. Samples containing a large amount of lipid had different ratios indicating the correction factor should be validated for plant type. Atemesia tridentata had a ratio of 1.84 and Carthamus tinctorius seeds had a ratio of 1.64.