Posted December 2008
Over the last 7 years we have been testing the hypothesis that if alfalfa was harvested in the fall “when ready”, alfalfa could be harvested anytime in the fall. We have defined as “when ready” as alfalfa at 40 to 50% bloom, regrowth of about 3 inches initiating from the bottom of the canopy, or a killing frost. Alfalfa in 2008 was harvested following a killing frost in early November, extremely late for Fargo. WKA-04 terminated this fall had a forage yield 4.7 tons/acre greater yield over the five years of this experiment when fall harvested compared with non-fall harvested. Stands were excellent this fall and would be considered fully productive. However, spring growth was delayed in fall-harvested plots indicating that winter injury could have occurred. Forage yields for the year however were significantly greater from fall-harvested plots. The purpose of this experiment is to future evaluate fall harvest effects in alfalfa.
WKA-08 was seeded March 27, 2007 to beat the injunction placed on Roundup Ready alfalfa. It is quite rare that we could seed on this date, the second week of April generally is as early as alfalfa seeding can be done at Fargo. DKA34-17RR was seeded at 13 lb/acre with a double-disc-opener drill into a well prepared seedbed. Stands were generally very good.
Forage was harvested with a Carter flail harvester on June 27 at 25% bloom, on July 22 at 30% bloom, and on September 29 when regrowth was initiating. Forage yield was 2.09, 1.45, and 1.85 tons/acre for the three harvests, respectively, totaling 5.39 tons/acre. This is the highest seeding-year yield ever obtained at Fargo. Forage yield for two cuts during the seeding year was 3.54 tons/acre, very similar to seeding-year yields over the last 10 years.
Forage yield was 1.8 tons/acre greater with a fall harvest than non-harvested in 2008 (Table 1). This yield advantage is very similar to previous experiments in the first year of production.