Development of the grassgro model in support of a drought management strategy for livestock enterprises

By R.D.H. Cohen, University of Saskatchewan

Abstract

This project arose from a perceived need for weather based crop insurance adjustments. GrassGro is a computer simulation model that predicts the growth and production of a wide range of pasture forage species from weather data. It can also predict the forage intake and production of various classes of grazing livestock. The objective of this project was to provide the Saskatchewan Crop Insurance Corporation with a computerized method of assessing the production of forage crops from weather data collected at various locations throughout the province of Saskatchewan.

This report provides information on the production of three pasture associations predicted from weather records collected at 81 locations in Saskatchewan or border towns in neighbouring provinces. The three pasture associations were alfalfa/grass, crested wheatgrass and mixed grass native range. Maximum forage production was simulated at each location using daily weather records from January 1, 1960 to December 31, 2000. Data for each year and the 41-year average were tabulated. Examples were provided to suggest how these data could be used for insurance adjustment purposes.

The complete data set and a working copy of the GrassGro software will be provided to the Saskatchewan Crop Insurance Corporation on compact disk. For the purpose of brevity, this report only presents examples from 5 locations Butte St Pierre, Hudson Bay, Val Marie, Estevan and Last Mountain Lake. The report also provides some discussion of the data and indicates that weather based predictions should consider more than just rainfall during the pasture growing season of a single year.