Mapping Agro-Climatic and Land Suitability for Switchgrass Production in North Dakota.

Switchgrass (Panicum virgatum L.) is considered a leading candidate for bioenergy feedstock. Switchgrass is native in western North Dakota but can be grown in the east. To reach biofuel production switchgrass must be adopted into the traditional cropping system. The adoption relies on switchgrass productivity and economic returns for producers. Economic benefits depend in part on the sustained break-even yield of switchgrass.  The yield threshold is site specific and is a function of climate and environmental variables such as temperature, precipitation, growing degree day, snow cover and soil types and characteristics, and crop management practices. The objective of the present study was to conduct a GIS and Remote Sensing-based land suitability evaluation for switchgrass production in North Dakota. Land suitability was determined as a function of agro-climatic factors governing switchgrass establishment, potential biomass yield, and long term land use practice in North Dakota.  Thresholds were defined for agroclimatic factors limiting switchgrass establishment and productivity. The Analytical Hierarchical Process technique was used to determine the relative weight of each of those factors and define risk areas for switchgrass establishment. The ALMANAC crop model was used to simulate the potential yield of switchgrass at different locations, and then simulated yields were interpolated at the state level. A multi-criteria analyses approach (MCAS-S) was utilized to produce a final switchgrass suitability map for North Dakota. Results show the presence of an east-west gradient in the areas best suited to sustain switchgrass biomass yield. The gradient is due to variations in the amount of precipitation throughout the growing season. Western North Dakota is subjected to intense period of drought that will compromise the production of sustained yields through the years.  GDD and sever winter conditions are other parameters that can negatively influence sustained switchgrass biomass yield.