Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 18, 2003
Publication Date: November 2, 2003
Citation: Skinner, R.H., Corson, M.S., Rotz, C.A., Sanderson, M.A. 2003. Simulating seasonal species composition and growth dynamics in grass/legume pastures [abstract]. Agronomy Abstracts. Paper No. A03-skinner116181-poster. 2003 CDROM. Technical Abstract: Improved multi-species plant growth models are need to simulate environmental and seasonal effects on productivity and species composition of temperate northeastern USA pastures. Plant growth components of the SPUR (Simulation of Production and Utilization of Rangeland) model were refined and parameterized for the species and environmental conditions of humid, temperate pastures. Although the SPUR model was developed for western rangelands, we hypothesized that the underlying concepts describing plant growth, nutrient uptake and root:shoot partitioning should be applicable to other ecosystems with appropriate parameterization. Spring, summer and autumn forage growth data for model parameterization and validation were collected in 2001, 2002 and 2003 from grazed orchardgrass/white clover pastures at two Pennsylvania locations. Simulations of relative species composition and pasture productivity appeared to be particularly sensitive to small changes in temperature optima for photosynthetic carbon uptake. Results from current simulations describing seasonal distributions in above- and below-ground biomass production, nitrogen concentration, and species composition will be discussed in relation to future model development.