My research is focused on developing a web-based forage species selection tool and estimating potential yield of key forage species grown in Oregon and Sichuan Province.
Our goal is to match appropriate species with each eco-region. Related to this class, the problem is how we can use the GIS spatial analyst tools to define and display a workable number of forage production eco-regions based on topography, climate, soil characteristics, land-use and land-cover, and agricultural systems.
Although there have been several important studies directed at defining ecoregions (Bailey, 1996; Thorson, 2003; Omernick, 2004), these have been based primarily on the Köppen Climate Classification System (1936) and broad groupings of species suitable for each zone. They are not helpful in quantifying potential annual forage yield or seasonal production profiles required for rational management of forage-livestock systems.
To provide useful guidance to Oregon and Sichuan Province farmers and ranchers, our agroecozone classification systems will use a hierarchical approach beginning with climate, with modifications due to physiography and land-use/land-cover, and soil characteristics.
Level I: Climate (Thermal Units and Precipitation)
Climate was chosen as the foundational level of the classification system due to the essential nature of temperature and precipitation in plant growth and development. Base spatial layers for climate factors will include extreme monthly cold and hot temperature, mean monthly maximum and minimum temperature, mean annual temperature, and mean annual, seasonal, and monthly precipitation. Climate-based indices will be developed to predict forage crop growth and development. These will include solar radiation and photosynthetically active radiation, accumulated thermal units (with various base temperatures), growing season length, and vernalization chilling days. For agricultural systems that include irrigation a soil water balance model will be applied.
Level II: Physiography, Land-use/Land-cover [Topography (DEM), MODIS Images]
The second level of the classification systems will involve physiography and land-use and land-cover. A DEM will be used to underlay the climate layers and identify terrain slope, with the following rankings: >60°, not useful; 60°— 50°, 30% can be useful for livestock; 50°— 40°50% can be useful; 40°— 30°, can be used as pasture; and >30°, useful as grassland (Zhang, Grassland management, 2010). Current land-use and land-cover will be characterized from current and historical MODIS satellite images, with particular focus on cropland, pastureland, and rangeland areas.
Level III: Soil Characteristics (pH, Drainage, Salinity)
Soil characteristics will be the final level of the hierarchy, since, to a large degree, these can be modified in agricultural systems. Spatial data layers will be obtained for soil type, pH, drainage classification, and salinity. Site specific data will be obtained for more detailed fertility information.