Yield and nutritive quality of sericea lespedeza ( Lespedeza cuneata) and little bluestem ( Schizachyrium scoparium) exposed to ground-level ozone

• Published in: Environmental pollution (1987) 2003-01, Vol.122 (3), p.313-322
• Main Authors: Powell, M.C, Muntifering, R.B, Lin, J.C, Chappelka, A.H
• Format: Article
• Language: English
• Subjects: Air Pollutants - adverse effects; Air pollution; Animal Feed; Biomass; Crops, Agricultural - drug effects; Fabaceae - drug effects; Forage quality; Lespedeza cuneata; Nutritive Value; Ozone; Ozone - adverse effects; Ozone - pharmacology; Poaceae - drug effects; Schizachyrium scoparium
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/S0269-7491(02)00331-7

Ground-level ozone decreased the nutritive quality of select warm-season forages for ruminant herbivores. Sericea lespedeza ( Lespedeza cuneata cv. Interstate 76) and little bluestem ( Schizachyrium scoparium cv. Aldous) were raised from seed in a glasshouse, transplanted into 5.7-l pots and placed into open-top chambers (OTC) on 6 June 1999. Following a 7-day adjustment period, each of six OTCs (duplicate OTCs per treatment) was ventilated with either air that had been carbon-filtered (CF) to remove ambient ozone (O 3); non-filtered (NF), representative of ambient air; or enriched to twice-ambient O 3 concentration (2X). Primary-growth forage was harvested on days 7, 32, 46, 59 and 72 following the start of fumigation, and regrowth forage from the first primary-growth harvest was harvested on days 36, 54 and 72 following the start of fumigation. Dry matter (DM) yield of either forage species did not differ among treatments except in the final regrowth period when yield of sericea lespedeza was greater for the NF than 2X O 3 treatment. In vitro DM digestibility (IVDMD) and concentrations of crude protein (CP), soluble phenolics (SP) and condensed tannins (CT) in primary-growth sericea lespedeza did not differ between treatments, but NF primary-growth forage had higher concentration of protein-precipitating tannins (PPT) than did 2X primary-growth forage. Concentrations of neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) were higher in NF and 2X than in CF primary-growth sericea lespedeza. Similarly, concentrations of NDF and ADL were higher, and IVDMD was lower for NF and 2X than for CF regrowth sericea lespedeza. Concentrations of ADF and ADL were lower, whereas IVDMD, in vitro NDF digestibility (IVNDFD) and concentrations of CP and SP were greater, in CF than in NF and 2X primary-growth little bluestem. Percentages IVDMD and IVNDFD and concentrations of CP and SP in NF primary-growth little bluestem were greater than those in forage exposed to 2X O 3 treatment. No significant differences were observed among treatments in percentages IVDMD and IVNDFD, or concentrations of cell wall constituents or SP in little bluestem regrowth. Nutritive quality of little bluestem was decreased by