Very good stands were obtained on all the South Dakota fields in 2001 except for the field at Ethan where no herbicides were applied (Figure 2). In the year after establishment, a herbicide application of atrazine and quinclorac enabled an adequate stand to develop at this site. Pre-emergence application of quinclorac was used on the fields at Huron and Bristol. Additional herbicides were used at Bristol to address specific weed problems. At Highmore, glyphosate was applied pre-emergence and atrazine and quinclorac were applied the spring after establishment. Stands on all fields have increased over time and have stabilized at stand frequencies of 60% to 80%. Harvestable yields were obtained the establishment year on both the Huron and Bristol fields.
The biomass at Ethan in Year 1 (2001) consisted mostly of weeds and was not harvested. Due to drought, the field at Highmore did not produce harvestable yields in either 2001 or 2002 (Year 1 and 2). In 2003 and 2004 which have been more “normal” in precipitation, switchgrass biomass yields on the South Dakota fields have ranged from about 3 to 5 tons/acre.
|Figure 2. Switchgrass biomass yields and stands for four farms in South Dakota. Year 1 is 2001 and Year 4 is 2004 for all fields.|
Return to previous section -- Results Nebraska
Return to contents
Next section -- Results North Dakota