Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/1999
Publication Date: N/A
Citation: Phillips, W.A., Albers, R. 1999. Chlorsulfuron and triasulfuron effect on forage production, animal performance and grain yield of winter wheat. Professional Animal Scientist. 15:141-147. Interpretive Summary: Winter wheat is a dual purpose crop that can be used to provide feed for grazing livestock during the winter and to produce grain for human consumption in the spring. Using herbicides to control weeds that would reduce grain yields must be applied during the winter, but their application may affect the amount of forage produced during the winter grazing period and as a result reducedanimal performance. Farmers are concerned that by optimizing grain yield, they may reduce animal performance. Over two production cycles, herbicides typically used to control weeds in winter wheat were applied to replicated pastures that were being grazed by young beef cattle. The herbicides used in this experiment did decrease weed infestation, but did not decrease forage production or the performance of animals grazing these plots. Wheat producers can use herbicides to control weeds that would decrease grain production without affecting the winter grazing livestock component of their enterprise.
Technical Abstract: Winter wheat (Triticum aestivum L.) is used for both forage and grain production throughout the US Southern Great Plains region. Management practices to increase grain yield may affect winter forage production and as a result, animal performance. The objective of this study was to determine the effect of applying herbicides in the winter to control broad leaf weeds on winter and spring forage production, animal performance and subsequent grain yield. Four 8-ha wheat pastures at each of two locations were established under no-till practices each fall, then randomly assigned within location to receive one of the following four treatments: 1) no winter herbicides, 2) chlorsulfuron, 3) chlorsulfuron plus metsulfuron or 4) triasulfuron. Herbicides were applied in December (Year 1) or January (Year 2) combination with 2,4-D. Stocker steers were used as grazers to determine animal performance during winter (December to March) and spring (March to May) grazing periods. Animal performance and beef production pe ha were not (P>.10) affected by the application of herbicides. Animal productivity was related to climatic conditions, which affected both the energy required by the animal for maintenance and the amount of forage produced. Winter and spring forage production was not affected (p>.10) by herbicide application. The amount of non-wheat biomass present at grain harvest was lower (p<.03) the harvesting index was higher (p<.01), and the number of seed head was higher (p<.01) for herbicide treated plots as compared to control plots. Among the herbicides used triasulfuron increased the number of seed heads and grain yield. Applying herbicides to winter wheat in the winter to control broadleaf weeds did not effect forage or animal production but did increase harvesting index.