Controls of plant and soil carbon in a semihumid temperate grassland

Journal Article · Sun May 01 04:00:00 EDT 1994 · Ecological Applications; (United States)

DOI:https://doi.org/10.2307/1941938· OSTI ID:7272044

Seastedt, T R; Coxwell, C C ^[1]; Ojima, D S; Parton, W J ^[2]

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1. Univ. of Colorado, Boulder, CO (United States)
2. Colorado State Univ., Fort Collins, CO (United States)

A modeling study evaluated photosynthetic pathways (C[sub 3], C[sub 4], or both) and management strategies in the foliage productivity and soil carbon characteristics of a semihumid temperate grassland with various combinations of climate change. Model values for plant and soil characteristics were obtained near Manhattan, Kansas, and the Manhattan climate record was used for actual monthly temperature and precipitation data for a 100-yr interval and average weather conditions. Monthly temperatures were increased 2[degrees]C, left unchanged, or decreased 2[degrees]C; annual precipitation was increased 6 cm, left unchanged, or decreased 6 cm. All possible combinations of temperature and precipitation were then used in 100-yr simulations. Regardless of climate, plant production was lowest for C[sub 3] grasses and highest for the mixed C[sub 3]-C[sub 4] community. The nominal seasonal pattern of precipitation favored an active C[sub 3] plant community in early to late spring, prior to the emergence of the C[sub 4] vegetation. However, the higher growth and water use efficiencies of C[sub 4] vegetation during summer contributed to the maximization response of the grasslands containing both C[sub 3] and C[sub 4] grasses. The relative importance of climate, photosynthetic pathways, and management activities (annually burned, burned every 4 yr, unburned, or lightly grazed) to plant production and soil carbon values were evaluated. Photosynthetic pathway and precipitation were the most significant single variables; the interaction between photosynthetic pathway and temperature was the most significant interaction term. Management treatments were by far the most important variable affecting soil carbon values, but 3[degrees]C warming did produce substantial soil carbon losses from C[sub 3] grasslands. Enhanced carbon fixation by the C[sub 4] and C[sub 3]-C[sub 4] plant communities negated the losses of soil carbon caused by enhanced soil respiration at warmer temperatures.

• OSTI ID: 7272044
• Journal Information: Ecological Applications; (United States), Journal Name: Ecological Applications; (United States) Vol. 4:2; ISSN 1051-0761; ISSN ECAPE7
• Country of Publication: United States
• Language: English

Related Subjects

560400* -- Other Environmental Pollutant Effects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AMBIENT TEMPERATURE
ATMOSPHERIC PRECIPITATIONS
BIOLOGICAL EFFECTS
C4 SPECIES
CARBON CYCLE
CHEMICAL REACTIONS
CLIMATIC CHANGE
ECOSYSTEMS
MATHEMATICAL MODELS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PLANTS
PRODUCTIVITY
RANGELANDS
SOILS
SYNTHESIS
TERRESTRIAL ECOSYSTEMS