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• 1. [Article] The influence of herbicides, phosphorus fertilization, and mechanical and chemical seedbed preparation on the establishment of alfalfa (Medicago sativa L.) and birdsfoot trefoil (Lotus conrniculatus L.)

  Initial establishment of legume forage crops is of prime importance in determining future forage and seed production. The objective of this study was to determine the influence of herbicides, phosphorus fertilization, and seedbed preparation on the establishment of alfalfa and birdsfoot trefoil. Experiments were designed to study the influence of herbicides applied alone or in combination with phosphorus fertilization on the establishment of alfalfa and birdsfoot trefoil. The phosphorus treatments consisted of different levels of P₂O₅ ...

  Citation × Citation Citation Abstract Copy Title: The influence of herbicides, phosphorus fertilization, and mechanical and chemical seedbed preparation on the establishment of alfalfa (Medicago sativa L.) and birdsfoot trefoil (Lotus conrniculatus L.) Author: Valdes Lamar, Ramon Initial establishment of legume forage crops is of prime importance in determining future forage and seed production. The objective of this study was to determine the influence of herbicides, phosphorus fertilization, and seedbed preparation on the establishment of alfalfa and birdsfoot trefoil. Experiments were designed to study the influence of herbicides applied alone or in combination with phosphorus fertilization on the establishment of alfalfa and birdsfoot trefoil. The phosphorus treatments consisted of different levels of P₂O₅ (0-50-100 pounds per acre) using two methods of application, broadcast and band. The herbicide treatments included Ethyl N, N-dipropylthiolcarbamate (EPTC) at 3 pounds active ingredient per acre (lb. ai/A) + 4-(2, 4-dichlorophenoxy) butyric acid (2, 4-DB amine) at 1 lb. ai/A; EPTC 3 lb. ai/A + 2-sec-butyl-4, 6-dinitrophenol (DNBP amine) at 2 lb. ai/A; 2, 2-dichloropropionic acid (dalapon) 5 lb. ai/A + 2, 4-DB amine 1 lb. ai/A; and an untreated control. EPTC was applied as a pre-plant incorporated treatment, whereas DNBP, 2, 4-DB, and dalapon were applied when the legumes were in the two to four true leaf stage of growth. Results for both alfalfa and birdsfoot trefoil were similar. Phosphorus applications did not enhance the establishment of the legumes. This may have been due to an adequate phosphorus supply already present in the soil. Phosphorus application without herbicide application resulted in weedy stands in which the legume yield was greatly reduced. The addition of phosphorus to herbicide treatments did not enhance the yield of alfalfa or birdsfoot trefoil any more than did the herbicide treatments alone. The effectiveness of herbicide applications in eliminating weed competition from the legume seedlings varied considerably. The best treatment for the establishment of both alfalfa and birdsfoot trefoil was the combination of EPTC + DNBP amine. This treatment gave good to excellent control of oats (Ayena spp.), ryegrass (Lolium spp.), cornflower (Centaurea cyanus L.), burnet (Sanguisorba spp.), henbit (Lamium amplexicaule L.), and mayweed (Anthemis cotula L.); fair control of wild radish (Raphanus raphanistrum L.), and wild mustard (Brassica kaber (D. C.) Wheeler var. pinnatifida (Stokes) Wheeler); and poor control of vetch (Vicia spp.). EPTC + 2, 4-DB amine was significantly better than dalapon + 2, 4-DB or the untreated control. This combination gave good to excellent control of oats, ryegrass, burnet, henbit, and mayweed, but poor control of wild radish, wild mustard, cornflower, and vetch. The dalapon + 2, 4-DB amine treatment was not significantly different from the check and resulted in poor control of all weed species. Two experiments were designed to compare the effectiveness of chemical seedbed preparation using 1, 1'-dimethyl-4, 4'-dipyridy-lium salt (Paraquat), mechanical seedbed preparation by use of a rotary tiller or a rake, and the chemical treatment of EPTC 3 lb. ai/A + DNBP amine 2 lb. ai/A on the establishment of alfalfa and birdsfoot trefoil. Duplicate experiments were conducted on alfalfa and birdsfoot trefoil. The treatment involving EPTC + DNBP amine was the most effective treatment for the establishment of both alfalfa and birdsfoot trefoil. Paraquat and rototilling or raking were ineffective in controlling weeds. In each case, the high weed population greatly decreased the alfalfa or birdsfoot trefoil yields. The poor results obtained with paraquat were due to poor weed emergence prior to the application of the chemical. Raking gave poor control of germinating weed seeds present in the top inches of the soil. The rotary tilling may have brought dormant weed seeds to the surface where they germinated and emerged after the tillage treatment. Title: The influence of herbicides, phosphorus fertilization, and mechanical and chemical seedbed preparation on the establishment of alfalfa (Medicago sativa L.) and birdsfoot trefoil (Lotus conrniculatus L.) Author: Valdes Lamar, Ramon Initial establishment of legume forage crops is of prime importance in determining future forage and seed production. The objective of this study was to determine the influence of herbicides, phosphorus fertilization, and seedbed preparation on the establishment of alfalfa and birdsfoot trefoil. Experiments were designed to study the influence of herbicides applied alone or in combination with phosphorus fertilization on the establishment of alfalfa and birdsfoot trefoil. The phosphorus treatments consisted of different levels of P₂O₅ (0-50-100 pounds per acre) using two methods of application, broadcast and band. The herbicide treatments included Ethyl N, N-dipropylthiolcarbamate (EPTC) at 3 pounds active ingredient per acre (lb. ai/A) + 4-(2, 4-dichlorophenoxy) butyric acid (2, 4-DB amine) at 1 lb. ai/A; EPTC 3 lb. ai/A + 2-sec-butyl-4, 6-dinitrophenol (DNBP amine) at 2 lb. ai/A; 2, 2-dichloropropionic acid (dalapon) 5 lb. ai/A + 2, 4-DB amine 1 lb. ai/A; and an untreated control. EPTC was applied as a pre-plant incorporated treatment, whereas DNBP, 2, 4-DB, and dalapon were applied when the legumes were in the two to four true leaf stage of growth. Results for both alfalfa and birdsfoot trefoil were similar. Phosphorus applications did not enhance the establishment of the legumes. This may have been due to an adequate phosphorus supply already present in the soil. Phosphorus application without herbicide application resulted in weedy stands in which the legume yield was greatly reduced. The addition of phosphorus to herbicide treatments did not enhance the yield of alfalfa or birdsfoot trefoil any more than did the herbicide treatments alone. The effectiveness of herbicide applications in eliminating weed competition from the legume seedlings varied considerably. The best treatment for the establishment of both alfalfa and birdsfoot trefoil was the combination of EPTC + DNBP amine. This treatment gave good to excellent control of oats (Ayena spp.), ryegrass (Lolium spp.), cornflower (Centaurea cyanus L.), burnet (Sanguisorba spp.), henbit (Lamium amplexicaule L.), and mayweed (Anthemis cotula L.); fair control of wild radish (Raphanus raphanistrum L.), and wild mustard (Brassica kaber (D. C.) Wheeler var. pinnatifida (Stokes) Wheeler); and poor control of vetch (Vicia spp.). EPTC + 2, 4-DB amine was significantly better than dalapon + 2, 4-DB or the untreated control. This combination gave good to excellent control of oats, ryegrass, burnet, henbit, and mayweed, but poor control of wild radish, wild mustard, cornflower, and vetch. The dalapon + 2, 4-DB amine treatment was not significantly different from the check and resulted in poor control of all weed species. Two experiments were designed to compare the effectiveness of chemical seedbed preparation using 1, 1'-dimethyl-4, 4'-dipyridy-lium salt (Paraquat), mechanical seedbed preparation by use of a rotary tiller or a rake, and the chemical treatment of EPTC 3 lb. ai/A + DNBP amine 2 lb. ai/A on the establishment of alfalfa and birdsfoot trefoil. Duplicate experiments were conducted on alfalfa and birdsfoot trefoil. The treatment involving EPTC + DNBP amine was the most effective treatment for the establishment of both alfalfa and birdsfoot trefoil. Paraquat and rototilling or raking were ineffective in controlling weeds. In each case, the high weed population greatly decreased the alfalfa or birdsfoot trefoil yields. The poor results obtained with paraquat were due to poor weed emergence prior to the application of the chemical. Raking gave poor control of germinating weed seeds present in the top inches of the soil. The rotary tilling may have brought dormant weed seeds to the surface where they germinated and emerged after the tillage treatment. Close