Submitted to: Journal of Range Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 20, 2002
Publication Date: May 1, 2003
Citation: HENDRICKSON, J.R., BERDAHL, J.D. SURVIVAL OF 16 ALFALFA CULTIVARS AND STRAINS SPACE PLANTED INTO A GRASSLAND. JOURNAL OF RANGE MANAGEMENT 56:260-265. 2003. Interpretive Summary: Alfalfa has potential to improve the productivity and quality of pastures in the Northern Great Plains. The successful identification of alfalfa cultivars that are grazing tolerant and adapted to the climatic extremes of the region is the first step in successfully incorporating alfalfa into perennial pastures. Sixteen different cultivars and strains of alfalfa were heavily grazed for four years to evaluate their ability to withstand grazing pressure. Entries that were developed in colder climates had higher survival than entries developed in regions with less extreme winter climate. This was true even for entries that had exhibited grazing tolerance in other regions. Survival declined dramatically during the winter of 2000 to 2001. All entries exhibited declines in survival but entries developed in regions with milder winter climates had the most severe declines in survival. Cultivar selection is a critical step in successfully incorporating alfalfa into rangelands. In selecting cultivars for use under grazing, producers should be aware of not only the grazing tolerance of cultivars but also their ability to survive climatic conditions.
Technical Abstract: Incorporation of alfalfa into pastures and rangelands can increase the quantity and quality of forage; however, many cultivars of alfalfa have limited ability to persist under grazing. Choice of a grazing tolerant cultivar is a prerequisite to successful incorporation of alfalfa into long-term pastures and rangelands. Sixteen entries of alfalfa were transplanted on a rangeland site in July 1996 at the Northern Great Plains Research Lab in Mandan, North Dakota, USA. Fifteen entries represented a range of potential grazing tolerance and `Vernal¿ was a check. Entries were grazed by cattle from 1997 to 2000 using the mob-grazing technique. Plant survival, basal area and stem numbers were recorded in the spring and fall of each year. The final survival evaluation occurred in May 2001. A large decline in survival between September 2000 and May 2001 may be attributed to low temperatures in November and December of 2000. Survival ranking of the entries changed between September 2000 and May 2001. Entries such as `Alfagraze¿, B-36 and Agripro ZG9415 which had the lowest fall dormancy also had the largest percentage drop in survival (43.0, 48.6 and 48.6 percentage points respectively). Entries developed in colder climates, such as SCMF 3713, `Anik¿ and Alaska Syn A had the least percentage point drops (2.8, 4.1 and 4.1 respectively). In May 2001, SCMF3713 had the highest survival (90%) and Vernal had the lowest (23%). Ten of the 16 entries had greater than 50% survival in May 2001. Several entries, most notably `Alfagraze¿, with proven persistence under grazing in other areas did not persist well in this northern climate. Total basal area in May and September 2000 and stem numbers in May 2000 were most strongly correlated with survival ( r = 0.46, 0.35 and 0.41 respectively). Despite the trend toward larger plants having better survival, several entries such as `Anik¿ had high survival without the large plant size. Producers should consider the origin of the grazing tolerant alfalfa cultivar they choose for use in pastures and rangelands of the Northern Great Plains.