Although there are not a lot of new red clover varieties, several companies and Universities have active red clover breeding programs. In some ways, red clover is the easiest species to make variety recommendations for. Simply put, “only plant certified seed of improved varieties, never plant common seed.” Bags of certified seed always have a blue certified seed tag. That is still great advice, especially with public varieties like Kenland, but some improved varieties from seed companies are not officially certified. If the seed bag does not have a blue tag then make sure you are dealing with a reputable forage seed company that you trust and make sure the variety has shown good performance in UK trials.
University of Kentucky research has shown that the difference between improved varieties and common seed can be over 6000 lb/acre higher yield over the life of the stand and 1 to 1 ½ years longer stand life. Sometimes you may “luck up” and find that the bag of cheap common seed you purchased was actually an overstock of an improved variety, but UK variety trials show that 9 times out of 10 certified seed of improved varieties showed higher yield and longer stand life. Most red clover breeders continue to make small steady improvements in stand persistence through improved resistance to root and crown diseases, but no variety yet has the ability to dependably survive more than 3 growing seasons.
Additional benefits of red clover in pastures was recently summarized by Dr. Michael Flythe from the USDA-ARS-FAPRU research lab in Lexington, KY. Our research is providing evidence that isoflavones in red clover can inhibit wasteful Hyper Ammonia-Producing Bacteria (HAB) in the rumens of cattle that are responsible for breaking down amino acids. As a result, the utilization of protein is improved for more efficient weight gain. In addition, the isoflavone biochanin A was determined to improve blood flow in ruminants exposed to toxic ergot alkaloids and, therefore, mitigate the effects of fescue toxicosis. In short, biochanin A causes vasodilation which opens up the constricted blood vessels of cattle grazing KY-31 tall fescue.
It is getting a little hard to make sense of new white clover varieties. In the past, the recommendation was to plant an improved variety of ladino white clover. Ladino types are closely related to the common Dutch types that seem to grow everywhere, but ladino white clover is taller with larger leaves that Dutch white. Therefore, larger plants and larger leaves produce higher yields. While that is true, ladino types typically do not live as long as Dutch whites. In recent years, many producers have stated that they could sacrifice some yield for longer persistence. Therefore, companies are now starting to release intermediate types that are hybrids between ladino and Dutch whites. For the most part, these intermediates look to be a good compromise between their two parents. Make sure though that you review yield and stand persistence information from variety trial publications before planting new intermediate UK has an additional publication that is a summary of all forage variety testing. All the forage species and all forage varieties that have been tested in Kentucky over the last 20 years are
included in the summary document entitled “Long Term Summary of Forage Variety Trials.” Just as with the regular reports the summary report is updated every year. This summary publication also includes a listing of the companies that have developed or are distributing each variety. In the summary document, variety yield is listed as a percentage based on the mean yield for a particular trial. In other words, a variety with 100 produced the same yield as the average or mean for the trial; below 100 designates below average yield; and above 100 above average yield. The take home message is that the best varieties are those that performed close to or above average.
One of the most useful parts of each summary table is the right hand column where the average performance over multiple locations and years is listed. The number in parentheses designates the number of the trials that a specific variety has been tested in KY and those varieties that don’t have an overall average listed were only planted at one test location. For example, certified Kenland has been in 28 trials in Kentucky over the last 18 years and it’s performance is 110% of the average of all the varieties entered in these trials. And there are several proprietary company varieties that show similar high yields. Conversely, when we planted seed from a bag that had Kenland stamped on the bag but did not have a certified seed blue tag it only yielded 70% of average.
Paying a little more for improved forage varieties can make a huge difference over time.