15 Apr Develop Your Plan For Alfalfa Stand Establishment Before Planting….
Good soil preparation is a key factor in alfalfa stand establishment. Regardless of your tillage methods, early germination and seedling growth of small-seeded legume species is dependent on three main planting factors:
- Seed placement at ¼ to ½ inch depth in most ag soils
- Good seed to soil contact in a firm seedbed with few or no clods larger than 1/4 inch
- Adequate soil moisture for germination and young seedling growth
Early weed control should also receive strong consideration in your alfalfa establishment decisions. Young alfalfa seedlings can be slower growing than many grasses and broadleaf weed species. There are several registered herbicides that offer a first line of defense in alfalfa establishment weed control.
Glyphosate-resistant varieties are an enticing option, but can be pricey considering the technology royalty. Glyphosate weed control won’t be stand-alone if you have to worry about glyphosate-resistant weed biotypes. Given all the lessons of herbicide rotation and weed resistance management principles that have become so important in recent years, the other herbicides registered for weed control in seedling alfalfa deserve consideration (see herbicide table reference). Herbicide rotation to include other herbicide classes and modes of action is especially important if you are already using glyphosate herbicides in other crops.
Regardless of the weed control method you choose for early alfalfa stand establishment, alfalfa plants develop a tap root around 40-60 days post-emergence. With tap root development, the recovery and regrowth rate of established alfalfa plants following clipping is faster than re-growth of most annual weed species. Once establishment is complete, a good stand of alfalfa smothers emerging weed seedlings, while any established weeds that persist in a young established alfalfa stand will have difficulty surviving the abuse of multiple cuttings per year, especially on the cutting schedule for dairy quality hay.
For a listing of herbicides registered for alfalfa, see the table appended to this article:
http://www.midwestforage.org/non-researchpdf/377.pdf
PHOTO CAPTION: These healthy alfalfa plants were established with a nurse crop, and were pulled out of the soil to illustrate early tap root development. Plants shown here at approximately 7 weeks post-emergence already have good tap root development following first clipping. With tap root development, the regrowth rate of alfalfa following clipping is faster than most annual weed species. (SW425TM Brand alfalfa)