The 2007-2008 winter at Fargo was about average through January, but below-average temperatures occurred during February, March, and April. Snow cover was adequate whenever temperatures dropped significantly below normal. As a result, little if any winter kill and only minor winter injury occurred on established varietal trials at both Fargo and Carrington.
Rainfall was nearly 4 inches above normal for the alfalfa growing season (October 2006-September 2007) and for the April through August growing season. Rainfall during June was 2.6, August 2.0, and September 2.9 inches above normal. With average to below-average temperatures and adequate rainfall, forage yields were above average in 2008.
Forage yield data for alfalfa varieties and experimental lines tested at Fargo and Carrington, ND in 2008 are presented in Tables 1 to 5. Insect and disease problems were not considered significant. Fusarium wilt reduced the stand of some Vernal plots in FA-05 during 2007, which had lingering effects in 2008. As a result, the coefficient of variation was greater in FA-05 than it should have been. Fusarium wilt was not a factor in FA-06 and FA-07. Likewise, insects and diseases were not considered a problem at Carrington in 2008, but winter injury and kill in 2006 had lingering effects on results of CA-05.
Forage yields on established dryland stands at Fargo averaged from 7.29 to 8.17 tons/acre (Tables 1 to 3), which is above average during the last 10 years. Forage yields of FA-05 averaged 21.17 tons/acre for the three production years (Table 1). The highest yielding variety without traffic was 6415 at 22.41 tons/acre, 7.5% greater than Vernal, but entries were not significantly different. Likewise, entries were not significantly different in FA-06 (Table 2) and FA-07 (Table 3).
FA-05 and FA-06 had a traffic treatment applied on half of all plots. The traffic treatment was one pass with a medium-size tractor 5 days after harvest. Forage yields averaged 0.21 and 0.36 tons/acre less in FA-05 (Table 1) and FA-06 (Table 2), respectively, in 2008 when traffic was applied. This represents only a 2.6 and 4.7% yield reduction with traffic, which is significantly less than previous years (average 9 to 9.5% previously). The reason traffic effects were less in 2008 compared with non trafficked treatments is unclear, but it may have been involved with the cool, wet growing season. The variety by traffic treatment interaction was significant for the fourth harvest of FA-05 while it was not significant for other harvests and in FA-06 like previous years. 4A421 was the most traffic tolerant variety over the 3 years in FA-05 while Vernal has been the most traffic tolerant variety in FA-06.
The fourth harvest was taken in November following a killing frost. Unlike the previous 3 years, regrowth from the crown had not initiated in October. We have taken the fourth harvest when the alfalfa reaches 40 to 50% bloom or regrowth is initiating (about 3 inches) for seven years without increased winter injury, but this is the first year we waited for a killing frost because neither condition was met. This is a real change in fall management of alfalfa that appears to be working.
Irrigated forage yields at Carrington averaged 4.37 tons/acre with three harvests (Table 4), which is about average for the third year of production. Forage yields averaged 18.44 tons/acre for the four years. Entries were not significantly different in 2008 or for the 4-year period. Forage yields for CA-07 (Table 5) averaged 5.67 tons/acre with no differences among entries.
The 2008 North Dakota alfalfa hay crop was estimated November 15 at 1.86 million tons, 45% less than 2007, by the North Dakota Agricultural Statistical Service. Per acre yield at 1.55 tons is down 30% from 2007. Alfalfa acreage was estimated at 1.55 million acres, down 6% from 2007, but near the long-term average.
These data are also available in the near future at:
http://www.ag.ndsu.edu/variety/index.htm
Alfalfa varietal data from 2004, 2005, 2006, and 2007 are available at: