Forage yield and quality of quaker comfrey (Symphytum uplandicum), alfalfa (Medicago sativa) and orchard grass (Dactylis glomerata)
Hart, R.H.; Thompson, A.J.IIi; Elgin, J.H.Jr; Mcmurtrey, J.E.IIi
Agronomy Journal 73(4): 737-743
Quaker comfrey (S. .times. uplandicum Nym.) has been promoted for years as a high-yielding protein-rich forage crop. Although considerable research has been done in other countries, almost none has been reported from the USA. Field trials on a Codorus silt loam (Fluvaquentic Dystrochrept) at Beltsville, Maryland and on an Archerson sandy clay loam (Aridic Argiustoll) at Cheyenne, Wyoming were established. At Beltsville, 3 cultivars of comfrey under 2 cutting schedules were compared to orchardgrass (D. glomerata L.) at 3 N rates, and to 3 cultivars of alfalfa (M. sativa L.) alone and in mixture with orchardgrass. At Cheyenne, 2 cultivars of comfrey at 3 N rates were compared with alfalfa. Forage dry matter yield was determined at both locations; protein concentration and in vitro dry matter digestibility were determined at Beltsville, and vitamin B12 concentration was determined at Cheyenne. Comfrey yields at both locations were about half those of alfalfa or orchardgrass at the same N rate. Closer spacing of comfrey probably would have increased yield. Protein concentration of comfrey was less than that of alfalfa or orchardgrass except at very high N rates. In vitro dry matter digestibilities of comfrey, alfalfa, and orchardgrass were 37, 62 and 61%, respectively. Contrary to some reports, comfrey forage did not contain detectable amounts of vitamin B12. Moisture content of fresh comfrey averaged 85% and was consistently higher than that of alfalfa or orchardgrass. In view of its low yield and digestibility in these tests, its high cost of establishment and weed control, and its low palatability to some animal species Quaker comfrey is not recommended as a forage crop.