ARS | Publication request: ADAPTING A RANGELAND MODEL TO PREDICT PASTURE COMPOSITION AND GROWTH IN TEMPERATE CLIMATES

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 22, 2003
Publication Date: October 1, 2003
Citation: Corson, M.S., Rotz, C.A., Skinner, R.H. 2003. Adapting a rangeland model to predict pasture composition and growth in temperate climates [abstract]. Agronomy Abstracts. Paper No. C06-corson372710-poster. 2003 CDROM.

Technical Abstract: Plant, soil, and water components of the SPUR (Simulation of Production and Utilization of Rangelands) model were incorporated into an Integrated Farm System Model (IFSM) to improve predictions of environmental and management effects on productivity and species composition of managed pastures. Developed for semi-arid rangelands, SPUR required moderate adjustment to represent temperate pastures adequately. In particular, the effects of soil moisture on root and shoot mortality and photosynthetic rates were adjusted to represent greater susceptibility of temperate plants to drought. In addition, a submodel to calculate symbiotic nitrogen fixation was added. Model predictions were evaluated against field data gathered from experimental pastures in Pennsylvania containing orchardgrass (Dactylis glomerata) and white clover (Trifolium repens). Discussion will focus on the model's ability to predict biomass production and relative species composition as well as on the degree to which the SPUR pasture model influences predictions of IFSM at the whole-farm scale.