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United States Department of Agriculture (USDA) 2009

GRASSLAND PRODUCTIVITY AND CARBON DYNAMICS : CONSEQUENCES OF CHANGE IN ATMOSPHERIC CO2, PRECIPITATION, AND PLANT SPECIES COMPOSITION, ...

Grassland Carbon

United States Department of Agriculture (USDA) Research, Education & Economics Information System (REEIS)

Titre : GRASSLAND PRODUCTIVITY AND CARBON DYNAMICS : CONSEQUENCES OF CHANGE IN ATMOSPHERIC CO2, PRECIPITATION, AND PLANT SPECIES COMPOSITION, ...

Identification : 3098-11220-005-00

Pays : Etats Unis

Durée : Oct 01, 2009 à Sep 30, 2014

Objectif
1. Determine CO2 effects on grassland plant production, plant species composition, and soil C dynamics. 1A. Determine responses of leaf gas exchange (C assimilation, stomatal conductance), plant water status, and plant production of tallgrass prairie assemblages to a subambient to elevated gradient in atmospheric CO2 concentration. 1B. Determine responses of soil respiration and soil organic matter pools (soil C dynamics) of tallgrass prairie assemblages to a subambient to elevated gradient in atmospheric CO2 concentration. 1C. Determine the response of species composition of tallgrass prairie vegetation to a subambient to elevated gradient in atmospheric CO2 concentration. 1D. Determine responses of photosynthetic C assimilation, biomass production, and bioenergy-relevant tissue constituents of the native grass species Panicum virgatum (switchgrass) to a subambient to elevated gradient in atmospheric CO2 concentration. 1E. Determine whether CO2 enrichment from subambient to elevated concentrations increases the potential for invasion of tallgrass prairie assemblages by a non-native grass species. 2. Determine effects of inter-annual variability in precipitation on productivity of switchgrass monocultures and mixed-species plantings of tallgrass prairie species. 2A. Compare responses of aboveground net primary productivity (ANPP) of switchgrass monocultures and mixtures of tallgrass prairie species to inter-annual variability in precipitation. 2B. Determine whether the frequency and magnitude of water limitation to ANPP of switchgrass and mixed-species plantings of prairie vegetation differ between a mollisol and vertisol soil. 3. Validate plant growth and biogeochemistry models to enable simulations of the impact of CO2 enrichment and precipitation variability on grassland production. 3A. Parameterize and validate the ALMANAC model with data from the CO2 gradient experiment and field-scale plots of switchgrass and prairie species. 3B. Parameterize and validate a coupled soil-plant-atmosphere-biogeochemistry model with plant and soil data from the CO2 gradient experiment. 4. Develop strategies to assess and manage the consequences for soil productivity, including carbon, of changing crop production strategies. 4A : Conduct evaluations of short-term carbon mineralization and water extractable organic C and N as a predictor of potential nitrogen mineralization in soil under conventional (inorganic) and organic fertilization. 5 : Develop new strategies to improve crop fertilizer use efficiency for agronomic, economic and environmental benefits. 5A : Make final determinations of runoff water quality impacts of fertilizer recommendations based on enhanced soil testing methods. 5B : Conduct final evaluations of liquid fertilizer injection guided by GPS auto-steer technology in terms of yield and economics.

Présentation : USDA

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