Alfalfa is considered one of the most important forage-legume species in South Dakota. It is a deep-rooted legume that grows best in moderate to well-drained soils. In South Dakota, under optimum growing and soil conditions, along with proper management, yields can exceed 3 to 4 tons DM/acre of hay when irrigated, and 1 to 2 tons DM/acre on dryland. Alfalfa is a crown-former legume, with high yield, high quality, persistent, with a very deep taproot, drought hardy, and winter hardy. Understanding how alfalfa grows, its harvest conditions, and its storage of carbohydrates in the root system are important aspects to determine its overall production throughout the state.
Planting & Harvest Considerations
Selecting an alfalfa harvest schedule with the quality of forage desired in mind should be considered. Most harvest schedule decisions will include date of cut, stage of maturity, interval between cuts, and cutting height. The interval between stage of maturity, yield, forage quality, and persistence is frequently used to decide when to harvest. For spring seedings without a companion crop, two cuttings can generally be made during the first year. This all depends on adequate rainfall patterns and optimum levels of soil nutrients.
The first harvest seeding year is when alfalfa is seeded in the spring and considerations of taking one or two cuttings in the same year are made. This harvest should be done after the flowers begin to appear, allowing greater energy reserves in the roots. Generally, alfalfa will reach this stage of development 60 to 70 days after emergence. Harvesting delays during this stage will cause large reductions in quality and decline in total yield over the season because fewer harvests are possible.
A Look Ahead to the Growing Season in Eastern South Dakota
One of the main concerns as we enter this growing season is winter injury and winter kill. We had some cold temperatures in South Dakota this past winter, but overall it was fairly mild. The lack of snow cover was one of the main concerns for producers as alfalfa plants can die if exposed to extremely cold temperatures, which are not uncommon. For the most part, alfalfa fields in Eastern South Dakota do not show much damage. However, newly seeded alfalfa stands which had a later cutting in 2015 have been showing some mild winter-kill. The late cutting might not have allowed enough regrowth and storage of carbohydrates in the root system.
At the start of this growing season we have had normal levels of moisture and precipitation which helped forages start their growth. New stands have been planted since mid-April and will continue, weather permitting. Areas of concern this growing season are moisture and rainfall patterns, insect infestations such as alfalfa weevils and potato leafhoppers, maintaining stem density, overall biomass production, and improving overall general forage quality for all feedstock forages.
Source: Karla Hernandez, South Dakota State University