Successful forage production and establishment begins with purchasing high quality seed. Quality of forage seed sold in the market varies, so it is important to understand how to evaluate and purchase good quality seed to ensure successful production from the start.
Using cheap seed is not a bargain. Rather, it will cost more due to the potential for poor stands, having to re-seed as a result of a low germination rate, and high foreign material in the seed. Sometimes cheap seed will contain undesirable weed seed. Therefore, it is important to buy high quality forage seed from the beginning to save time, money, and energy. Here are guidelines and things to consider for purchasing good quality forage seed.
Germination: Having good seed germination is very important for good stand establishment. If you buy seed with a very low germination rate, you must buy and plant more seeds; otherwise stand establishment might be a failure. The germination rate for the seed you are purchasing will be listed on the seed tag. If the seed is more than a couple of years old or has been stored under adverse conditions it would be wise to have the seed germination re-tested. Most certified forage seeds (labeled with a blue tag) have greater than 95% germination rate.
Pure Seed: Having a high percentage of pure seed of the forage species and variety your purchase is as important as having a high germination rate. Percent pure seed will be listed on seed label. If percent pure seed is low, then your seed will contain foreign material such as other undesirable crop seeds, weed seeds, inert matter, and hard seeds. Pure live seed (PLS) is calculated by the product of germination rate and pure seed rate (or purity). Recommended seeding rates are often based on PLS.
Weed Seed: The percent of seed which are weed species can be seen on the label. Certified seed should not contain any noxious weeds and a low percentage of non-noxious weeds. You obviously don’t want to purchase seed contaminated with weed seed. Often, the weed seed you would introduce would be difficult to control in the crop you are planting (otherwise the weeds wouldn’t have contaminated the crop that was harvested for seed). Also, if the seed you are planting is coming from a different part of the country or state, you could introduce weeds that might not be on your farm currently. Once you establish these weeds, it will be very difficult to manage them
Inert Matter: Sometimes low quality forage seed contains a high percentage of inert material: sticks, stems, broken seeds, sand, and other material. The percent of this material will be listed on the seed tag. A high percentage of inert matter is not desirable for good stand establishment.
Hard Seed: On the label, you will see the amount of hard seed in the seed lot. This tells you the percentage of seed which is viable but which will not germinate immediately due to a hard or waxy seed coat. Time or scarification (breakdown of hard seed coats) is required to allow moisture penetration. Seed germination of some species is regulated by a second set of internal germination conditions (stratification). This mechanism is for enabling the seed to germinate under more favorable conditions. An example of breaking this type of dormancy would be the seed requiring several short freeze-and-thaw cycles to prevent germinating too early in the spring and being susceptible to freeze damage.
Inoculation on Legume Seeds: Rhizobium bacteria are essential for symbiotic nitrogen fixation with legumes. Sometimes legume seed will be pre-inoculated with rhizobium bacteria. If legume seeds such as alfalfa, red clover, white clover, birdsfoot trefoil, or kura clover are not pre-inoculated, you need to buy the inoculants separately and apply them with the seed for successful stand and rhizobium establishment. Rhizobium bacteria are specific to certain legume plants, and this is very important since the wrong type of bacteria (inoculant) can be useless. For example, inoculants used for alfalfa cannot be used for birdsfoot trefoil although inoculants for alfalfa can be used for inoculating white, ladino, or red clover. The inoculants should be stored in a refrigerated or cool, shaded area until you use them.
Follow the University’s Forage Variety Testing Results if Available: Many universities, including K-State, conduct forage variety testing. K-State conducts forage variety testing for alfalfa and tall fescue. When selecting a variety there are many different traits to consider, besides yield, such as forage quality, maturity ratings, and seasonal production patterns. Choosing the best performing variety from the university’s forage variety testing can be a very helpful tool for making variety selections and a successful crop.
Doo-Hong Min, Southwest Area Crops and Soils Specialist
John Holman, Cropping Systems Agronomist, Southwest Research-Extension Center