In some parts of the country, one of the best-kept secrets for good pasture performance may be a forage legume called birdsfoot trefoil. Trefoil, sometimes just called “lotus” because of its Latin name (Lotus corniculatus ), is a high quality forage plant that’s adapted to most parts of the United States. It performs well on soils ranging from somewhat poorly drained, acidic soils to dry, alkaline soils and is hardy across many different climates, from the frigid northern parts of the United States to the intermountain west and all the way down to the southeast.
Trefoil has many of the same characteristics of other forage legumes like alfalfa or red clover. It hosts a type of bacteria that can “fix” atmospheric nitrogen and turn it into forms that nourish the stand, and it produces high protein forage that’s palatable and digestible. Trefoil also has some unique characteristics that actually make it more useful as a feed than some of the more-common legumes. It contains substances called tannins that help protect its protein from being broken down in the rumen, but allow that protein to be broken down in the abomasum so that the livestock eating it can make better use of it. This bypass protein results in very good milk or meat production, while decreasing the level of milk urea nitrogen and the nitrogen content of the urine. In addition, the tannins in trefoil allow livestock to be able to graze it free-choice, even in relatively pure stands, without any danger of bloat. And if that’s not enough, trefoil has been shown to serve as a natural defense against internal parasites.
Trefoil has an indeterminate growth habit, which means that the same plant can have leaf and flower buds, open blossoms, green seed pods, and mature seeds. Because of this, even older plants typically have some very high quality forage that grazing livestock can select.
Trefoil is present in almost every state, and there are varieties that are suited to almost every region of the country. Even so, there a lot of places where farmers aren’t using this versatile species. If you graze and don’t have any trefoil in your pastures, I really encourage you to consider adding this plant to your swards. Check with your regional extension forage specialists to find out which varieties work best in your area and start by establishing even a small area.
You can establish it by including some in a new seeding, or you can interseed or frost seed into an existing pasture. Whatever method you use, you need to keep a few things in mind in order to establish it successfully. First, make sure you either buy inoculated seed that has the correct species of Rhizobium bacteria already on it, or buy the inoculant and apply it yourself. When you seed trefoil, you should generally be including 4-8 lb of seed per acre. Trefoil seedlings are quite tender and take a while to establish. There’s a saying among farmers who plant trefoil: The first year it sleeps, the second year it creeps, and the third year it leaps. While trefoil is establishing, it’s very important to keep the other plants in the stand from shading it out, so clipping the pastures occasionally might be necessary.
It grows best where the pH is between 6.0 and 6.5, but it tolerates a range of 5.5 to 7.5 very well. Like every legume, it needs a fair amount of calcium, phosphorus, potassium, and sulfur to really do well, and boron is an important micronutrient as well.
Trefoil plants don’t grow back very well from the crowns, but rather the new growth comes from buds along joints on the stem. This means that you shouldn’t mow or let the stock graze trefoil close to the ground. Leave at least four inches of stem to help the plant recover quickly. Individual trefoil plants have varying life spans, but trefoil is a prolific seed producer. Every few years, allow the stand to grow long enough before you cut or graze it so that you see some brown seed pods. By that time, there should be enough viable seed available for the stand to perpetuate itself by seeding.
In many areas, once you get some trefoil established, even in a small area, it will continue to spread and colonize your whole farm. One word of caution—if you have native prairies in your area, trefoil may become a problem by invading those and crowding out the original plants. In almost every other case, trefoil should be a welcome and helpful addition to the mix of species in your pastures and hayfields.
If you have access to an internet connection and a spare hour, you can learn a lot more from listening to an eOrganic webinar that was presented in May by Dr. Jennifer MacAdam of Utah State University.