inoculated with Rhizobium lupini bacteria,which are comnetition for light becomes too great and before the root system and adequate atmospheric companion crop begins to lodge.For pure seedings of mseed necessitates that it be placed no trefoil,chemical weed control is generally necessary deeper than 1/4 inch in the soil to achieve maximum stands eeds grow faster and are more competitive Trefoil establishment in soils with a pH less than 5.6 may result in molybdenum(Mo)deficiencies.Molybdenum ation.W hen needed, of the trefoil stand NheaebaaevESTaceaeTesniae taken at 1/10th bloom and a second cutting in mid to late ield 25 Emergence trefoil plant is totally defoliated in midsummer when root eserves are low alfalfa to Fusar -type 1.5 survive as long as afafa.To maintain a stand of trefoil.it Depth of Seeding(inches) is necessary to use a management system that allows the oll to res Memoir 261 spring t a grass mixture.Trefoil will compete under continuous grazing better than alfalfa.However,clo continuous Firming the soil before and after planting will improve grazing is not recommen ontact,which improves y the seed and uti mate he summer acre are considered adequate under normal conditions Harvesting or grazing betw than are possible survival and growth the following spri Birdsfoot trefoil quality is greater than that of alfalfa obtain a 50:50 birdsfoot trefoil:grass stand are listed in bypas tein and sma ems )However.leaf loss during hay making may be greater than alfalfa.When grazed,trefoil is development seedling vigor.stand density.and vield of TteSedngatesorbastorteolwtasngegrasn Species Ib/A Birdsfoot trefo Species Bud 6-8 ith any one ese grasses TDN chardgrass 2 oth bror Source:Penn State Univ.Agric.Exp.Stn.Bull.753. imothy inoculated with Rhizobium lupini bacteria, which are specific for birdsfoot trefoil. This will ensure sufficient nodulation of the root system and adequate atmospheric nitrogen fixation. Trefoil’s small seed necessitates that it be placed no deeper than 1/4 inch in the soil to achieve maximum stands and yields (Figure 2). A smooth, firm seedbed will greatly facilitate accurate depth placement of the seed. Early spring seedings are generally more successful than late summer seedings. Figure 2. Effect of seeding depth on birdsfoot trefoil emergence and yield. (Source: Cornell Univ. Agric. Exp. Stn. Memoir 261) 0 0.5 1 1.5 2 0 25 50 75 100 Percent Depth of Seeding (inches) Yield Emergence Firming the soil before and after planting will improve the seeding depth and seed-to-soil contact, which improves moisture uptake by the seed and ultimately enhances germination and emergence. Seeding rates of 8 to 10 lb per acre are considered adequate under normal conditions. Grass-birdsfoot trefoil mixtures are commonly used to obtain higher yields than are possible with a pure stand of trefoil. A grass-trefoil mixture can reduce trefoil lodging and curing time for hay. Recommended seeding rates to obtain a 50:50 birdsfoot trefoil:grass stand are listed in Table 2. Trefoil’s low seedling vigor has brought into question the value of a companion or nurse crop when establishing this legume. Small grain companion crops reduce root development, seedling vigor, stand density, and yield of Table 2. Seeding rates for birdsfoot trefoil with a single grass in mixture. Species lb/A Birdsfoot trefoil 6-8 with any one of these grasses Orchardgrass 2-4 Perennial ryegrass 4-8 Reed canarygrass 6-8 Smooth bromegrass 6-8 Timothy 2-4 trefoil. If a companion crop is used, it should be seeded in 18-inch row spacings and removed early before competition for light becomes too great and before the companion crop begins to lodge. For pure seedings of trefoil, chemical weed control is generally necessary because most weeds grow faster and are more competitive than trefoil. Trefoil establishment in soils with a pH less than 5.6 may result in molybdenum (Mo) deficiencies. Molybdenum is an essential nutrient for nitrogen fixation. When needed, Mo can be applied as a seed coating. This method of application should provide sufficient Mo levels for the life of the trefoil stand. HARVEST MANAGEMENT When trefoil is harvested as hay, the first cutting should be taken at 1/10th bloom and a second cutting in mid to late August. Sufficient time for regrowth between cuttings or grazing is recommended to maintain the stand. Root reserves may not be sufficient to initiate regrowth if the trefoil plant is totally defoliated in midsummer when root reserves are low. Trefoil is not as resistant as alfalfa to Fusarium-type diseases. Therefore, individual trefoil plants will not survive as long as alfalfa. To maintain a stand of trefoil, it is necessary to use a management system that allows the trefoil to reseed itself. Heavy grazing pressure may be needed in the spring to reduce lush growth and to allow trefoil to better compete in a grass mixture. Trefoil will compete under continuous grazing better than alfalfa. However, close, continuous grazing is not recommended because trefoil regrowth depends on energy supplied by top growth. Unlike alfalfa, trefoil does not maintain high levels of root reserves during the summer. Harvesting or grazing between September 1 and the first killing frost is not recommended. This period is needed to allow root reserves to accumulate to improve winter survival and growth the following spring. Birdsfoot trefoil quality is greater than that of alfalfa because of increased “bypass” protein and smaller stems. Loss of quality with maturity is less pronounced with trefoil than alfalfa (Table 3). However, leaf loss during hay making may be greater than alfalfa. When grazed, trefoil is more palatable than alfalfa and produces greater average daily gains and meat yield per acre for heifers (Table 4) and Table 3. Total digestible nutrient (TDN) content of alfalfa and birdsfoot trefoil at three maturity stages (three-year averages). Maturity Species Bud 10% bloom 50% bloom % TDN Alfalfa 62.5 54.1 52.1 Birdsfoot trefoil 65.8 62.6 58.2 Source: Penn State Univ. Agric. Exp. Stn. Bull. 753