No description available.

No description available.

No description available.

Digitized by Kansas Correctional Industries

Digitized by Kansas Correctional Industries

Johnsongrass (Sorghum halepense) is one of the most troublesome weeds in the southeastern United States. -everal herbicides have been developed to combat johnsongrass, and many new experimental herbicides with high johnsongrass control potential are presently being tested. Two of these new experimental herbicides for johnsongrass control in soybeans (Glycine max) are sethoxydim and MBR 22359. Field experiments were conducted in 1981 and 1982 to evaluate the effectiveness of MBR 22359 preemergence and postemergence, sethoxydim in single and split applications, trifluralin in combination with mefluidide, or with glyphosate or sethoxydim in the wick, and alachior in combination with glyphosate or sethoxydim in the wick for rhizome johnsongrass control in soybeans. In 1982 fluchioraiin was also tested for rhizome johnsongrass control in soybeans. In both years MBR 22359 was applied at 2.2, 3.4, and 4.5 kg/ha preemergence, and at 1.1 and 2.2 kg/ha postemergence. In 1981 sethoxydim was applied in single applications at 0.3, 0.4, and 0.7 kg/ha early postemergence, 0.7 kg/ha late postemergence, and in split applications early postemergence and late postemergence respectively at 0.2 plus 0.2, 0.3 plus O.', 0.4 plus 0.4, and 0.4 plus 0.2 kg/ha. In 1982 sethoxydim was applied in single applications at 0.2, 0.3, 0.4, and 0.6 kg/ha early postemergence, and in split applications early postemergence and late postemergence respectively at 0.2 plus 0.1, 0.2 plus 0.2, 0.3 plus 0.1, 0.3 plus 0.2, and 0.4 plus 0.2 kg/ha. In 1981 and 1982 trifluralin at 1.1 kg/ha was applied in combination with mefluidide at 0.3 kg/ha early postemergence, mefluidide at 0.3 kg/ha early postemergence plus mefluidide at 0.3 kg/ha late postemergence, mefluidide at 0.3 kg/ha early postemergence in combination with glyphosate plus water (1:2, v/v) directed postemergence, sethoxydim plus oil plus water (2:1:3, v/v) directed postemergence, or with glyphosate plus water (1:2, v/v) directed postemergence in the rope wick applicator. Alachlor was applied at 3.4 kg/ha in combination with sethoxydim plus oil plus water (2:1:3, v/v) or with glyphosate plus water (1:2, v/v) directed postemergence in the rope wick applicator. In 1982 fluchloralin was applied at the rate of 2.2 kg/ha. Sethoxydim single and split application treatments at all rates employed excellent rhizome johnsongrass control in 1981 and 1982. No soybean injury was noted and good yields were obtained where sethoxydim was applied. MBR 22359 preemergence treatments provided good to excellent rhizome johnsongrass control. soybean injury and yield reductions were noted with the MBR 22359 postemergence and the 4.5 kg/ha preemergence treatments in 1981. No significant differences in yields were found between any of the herbicide treatments in 1982. Trifluralin combinations and alachlor combinations provided poor to fair rhizome johnsongrass control in both years. Soybean injury was noted for the trifluralin combination treatments that contained mefluidide. Yields were generally not as high for the trifluralin combinations and alachlor combinations as they were for the sethoxydim, and the lower rate MBR 22359 preemergence treatments in 1981. Fluchloralin provided extremely poor rhizome johnsongrass control in 1982.

The spread of invasive weeds continues to be a serious economic and environmental threat. Weed prevention has the potential to stop weeds before they become well established in an area conserving time, energy, and resources. Unfortunately, weed prevention is often overlooked. Weed Prevention Areas (WPAs) are a relatively new tool developed to help improve the application of weed prevention. They are cooperatively managed areas that focus on implementing prevention and early detection strategies at a community level. The purpose of this research was to establish baseline data that will be used to evaluate the overall effectiveness of the WPA concept, as well as to produce materials to assist individuals with the development of a WPA. Two rural communities, with new WPAs, were each paired with a non-WPA community for data collection purposes. On-the-ground GPS vegetation inventories were conducted to determine the initial abundance and distribution of selected invasive weed species. This information was then used to demonstrate how to prioritize species and sites within a WPA in order to utilize limited resources more efficiently. A mail-back survey was also conducted to evaluate landowners' current opinions and activities in regards to prevention and control. In general, weed prevention was viewed as an important part of integrated weed management, but fewer than half of all respondents applied prevention strategies on their property. The failure to implement prevention strategies was attributed to limited funding and resources, a lack of weed prevention knowledge, and a high level of perceived risk. The knowledge gained from this research was then used to create Step-By-Step Guidelines for Establishing a Weed Prevention Area. These Guidelines provide interested individuals the resources necessary to successfully organize a WPA in their community. In addition, four wildland weed mapping methods were evaluated to identify their strengths and weaknesses. There was no difference in the estimation of patch size or location between the buffered point, screen-drawn, and perimeter walked methods. In most situations, time and distance factors favor the selection of either the buffered point or screen-drawn method. If patch shape is an important consideration, the perimeter-walked or buffered point method should be selected.

There is a great deal of vegetation literatures about vegetation of forest and alpine grass in Taiwan, but the weed vegetation survey often investigates the species only. As the study of vegetation in Taiwan is for away from completeness, and weed is important to biodiversity is imperative, therefore the study of weed vegetation. The study selected weed vegetation in Daliau Township as study area, and surveyed floristic composition and environmental factors. The study used Branu-Blanquet method, and set up 304 plots. Classification of the vegetation types was conducted by cluster analysis and tabular comparison method, and following the treatment of Taiwan vegetation classification system. Detrended correspondence analysis (DCA) and nonmetric multidimentional analysis (NMDS) used to clarify the relationship between vegetation composition and environmental factors. The lower two levels of the hierarchy, alliance and association, were based on floristic composition according to the floristic-sociological concept of diagnostic species. The relationships of floristic composition and environmental factors were not significant, and this might be caused by that the composition of weed communities can quickly responsed to weather and human disturbances. The resultant system consisted of 2 classes, 3 formations, 21 alliances, 37 associations, 6 tentative vegetation types and 10 intermediate vegetation types. It may supply some misgiving of study of vegetation in Taiwan.

Field studies were conducted during the 2003 and 2004 growing seasons to: 1) evaluate the control of silverleaf nightshade and western ragweed, and (2) assess the forage tolerance of Coastal and Tifton 85 bermudagrass hybrids using tank mix combinations of diflufenzopyr. Herbicides that were evaluated in each study included picloram, multiple rates of picloram with diflufenzopyr, triclopyr, triclopyr with diflufenzopyr, dicamba + diflufenzopyr, and diflufenzopyr alone. Visual ratings were taken on the weed control experiments approximately 30, 60 and 90 days after treatment. Phytotoxicity ratings were taken prior to each harvest of the Coastal and Tifton 85 varieties to determine influence of each herbicide treatment. Each bermudagrass variety was harvested twice during each growing season to determine dry matter yield and quality. Forage quality, including crude protein, acid detergent fiber, and neutral detergent fiber, was assessed using near infrared reflectance spectroscopy. Adding diflufenzopyr to triclopyr did not consistently increase control of silverleaf nightshade or western ragweed. In general, picloram + diflufenzopyr and picloram applied alone provided the greatest control of both species at the highest rate of picloram. Increased efficacy was more evident from the addition of diflufenzopyr to picloram in 2004 on western ragweed. By the final ratings in both experimental years, dicamba + diflufenzopyr provided no more than 76% control of either species. Both forage varieties showed significant variability in phytotoxicity between years. Although observed levels of growth reduction were relatively high at the first harvest in 2003, no treatment exceeded a 10% growth reduction by the second harvest for either forage variety. In addition, the only significant reduction in dry matter yield occurred at the first harvest of Coastal in 2003 from picloram + diflufenzopyr applied at the highest rate.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.