Cultivation and Reduced-Rate Herbicides Weed Control in Sugarbeet Grown for Biofuel

2018 ◽  
Vol 32 (6) ◽  
pp. 726-732
Author(s):  
W. Carroll Johnson ◽  
Theodore M. Webster ◽  
Timothy L. Grey ◽  
Xuelin Luo
Keyword(s):  
United States ◽  
Weed Control ◽  
Southeastern United States ◽  
Integrated System ◽  
Cool Season ◽  
Evening Primrose ◽  
Limited Role ◽  
Reduced Rate ◽  
Main Effects ◽  
Sugarbeet Yields

AbstractSugarbeet, grown for biofuel, is being considered as an alternate cool-season crop in the southeastern United States. Previous research identified ethofumesate PRE and phenmedipham + desmedipham POST as herbicides that controlled troublesome cool-season weeds in the region, specifically cutleaf evening-primrose. Research trials were conducted from 2014 through 2016 to evaluate an integrated system of sweep cultivation and reduced rates of ethofumesate PRE and/or phenmedipham+desmedipham POST for weed control in sugarbeet grown for biofuel. There were no interactions between the main effects of cultivation and herbicides for control of cutleaf evening-primrose and other cool-season species in two out of three years. Cultivation improved control of cool-season weeds, but the effect was largely independent of control provided by herbicides. Of the herbicide combinations evaluated, the best overall cool-season weed control was from systems that included either a 1/2X or 1X rate of phenmedipham+desmedipham POST. Either rate of ethofumesate PRE was less effective than phenmedipham+desmedipham POST. Despite improved cool-season weed control, sugarbeet yield was not affected by cultivation each year of the study. Sugarbeet yields were greater when treated with any herbicide combination that included either a 1/2X or 1X rate of phenmedipham+desmedipham POST compared with either rate of ethofumesate PRE alone or the nontreated control. These results indicate that cultivation has a very limited role in sugarbeet grown for biofuel. The premise of effective weed control based on an integration of cultivation and reduced herbicide rates does not appear to be viable for sugarbeet grown for biofuel.

Cool-Season Weed Control Using Ammonium Nonanoate and Cultivation in Organic Vidalia® Sweet Onion Production

2017 ◽  
Vol 32 (1) ◽  
pp. 90-94
Author(s):  
W. Carroll Johnson ◽  
Xuelin Luo
Keyword(s):  
Weed Control ◽  
Cropping Systems ◽  
Clove Oil ◽  
Cool Season ◽  
Control Cool ◽  
Evening Primrose ◽  
Statistical Interactions ◽  
Degree Of Control ◽  
Certified Organic ◽  
Main Effects

AbstractAmmonium nonanoate is registered for weed control in certified organic cropping systems and may be useful to control cool-season weeds in organic Vidalia® sweet onion production. Ammonium nonanoate combined with tine-weeder cultivation was evaluated for weed control in organic onion in Georgia. There were no statistical interactions between main effects of herbicides and cultivation with a tine weeder for cool-season weed control and onion yield, indicating that ammonium nonanoate does not improve weed control compared with cultivation. Ammonium nonanoate at 4% and 6% did not adequately control weeds and onion yields were reduced. Ammonium nonanoate at 8% and 10% controlled cutleaf evening-primrose and lesser swinecress equal to the standard of d-limonene (14%), but the degree of control did not consistently protect onion yields from losses due to weeds. These results are in agreement with previous studies using clove oil and pelargonic acid. There is no advantage to using ammonium nonanoate for cool-season weed control in organic Vidalia® sweet onion production.

Managing Cool-Season Weeds in Sugarbeet Grown for Biofuel in the Southeastern United States

2018 ◽  
Vol 32 (4) ◽  
pp. 385-391 ◽  
Author(s):  
W. Carroll Johnson ◽  
Theodore M. Webster ◽  
Timothy L. Grey ◽  
Xuelin Luo
Keyword(s):  
United States ◽  
Weed Control ◽  
Coastal Plain ◽  
Southeastern United States ◽  
Temperature Limit ◽  
Field Trials ◽  
Maximum Temperature ◽  
Severely Injured ◽  
Wild Radish ◽  
Cool Season

AbstractSugarbeet, grown for biofuel, is being considered as an alternate cool-season crop in the southeastern U.S. coastal plain. Typically, the crop would be seeded in the autumn, then grow through the winter and be harvested the following spring. Labels for herbicides registered for use on sugarbeet grown in the traditional sugarbeet production regions do not list any of the cool-season weeds common in the southeastern United States. Field trials were initiated near Ty Ty, GA, to evaluate all possible combinations of ethofumesate applied PRE, phenmedipham+desmedipham applied POST, clopyralid POST, and triflusulfuron POST for cool-season weed control in sugarbeet. Phenmedipham+desmedipham alone and in combination with clopyralid and/or triflusulfuron effectively controlled cutleaf eveningprimrose, lesser swinecress, henbit, and corn spurry when applied to seedling weeds. Ethofumesate PRE alone was not as effective in controlling cool-season weeds compared to treatments containing phenmedipham+desmedipham POST. However, ethofumesate PRE applied sequentially with phenmedipham+desmedipham POST improved weed control consistency. Clopyralid and/or triflusulfuron alone did not adequately control cutleaf eveningprimrose. Triflusulfuron alone effectively controlled wild radish. In the 2013–2014 and 2014–2015 seasons, December-applied POST herbicides did not injure sugarbeet. However, in the 2015–2016 season POST herbicides were applied in late October. On the day of treatment, the maximum temperature was 25.4 C, which exceeded the established upper temperature limit of 22 C for safe application of phenmedipham+desmedipham, and sugarbeet plants were severely injured. In the southeastern United States, temperatures frequently exceed 22 C in early autumn, which may limit phenmedipham+desmedipham use for controlling troublesome cool-season weeds of sugarbeet in the region. Weed control options need to be expanded to compensate for this limitation.

Interaction of Prodiamine and Flumioxazin for Nursery Weed Control

2010 ◽  
Vol 24 (4) ◽  
pp. 504-509 ◽  
Author(s):  
Glenn Wehtje ◽  
Charles H. Gilliam ◽  
Stephen C. Marble
Keyword(s):  
United States ◽  
Weed Control ◽  
Southeastern United States ◽  
Cost Effective ◽  
Fresh Weight ◽  
Weed Species ◽  
Rate Range ◽  
Nursery Production ◽  
Control Research ◽  
Large Crabgrass

Both prodiamine and flumioxazin are used in the nursery production and landscape maintenance industries in the southeastern United States for preemergence weed control. Research was conducted to determine whether a tank mixture of these two herbicides would be more effective than either component applied alone. Prodiamine alone, flumioxazin alone, and a 72 : 28 (by weight) prodiamine–flumioxazin mixture were each applied at a series of rates to containers filled with a pine bark–sand substrate that is typical for nursery production in the southeastern United States. Our intent was to have a rate range that hopefully extended from ineffective to lethal for each treatment series. Subsequent to treatment, containers were overseeded with either large crabgrass, spotted spurge, or eclipta. Percent control was determined by comparing treated weed foliage fresh weight to that of the appropriate nontreated control at 6 and 12 wk after application. ANOVA followed by nonlinear regression was used to evaluate the interaction of prodiamine and flumioxazin when combined and to determine the rate of each treatment series required for 95% control (if applicable) for each of the three weed species. Results varied with weed species. The mixture was synergistic and more cost effective than either of the components applied alone in controlling spotted spurge. With respect to large crabgrass control, the mixture was additive and slightly more cost effective than the components. Eclipta could only be controlled with flumioxazin, and this control was antagonized by the addition of prodiamine.

scholarly journals Climatology and Environmental Characteristics of Extreme Precipitation Events in the Southeastern United States

2015 ◽  
Vol 143 (3) ◽  
pp. 718-741 ◽  
Author(s):  
Benjamin J. Moore ◽  
Kelly M. Mahoney ◽  
Ellen M. Sukovich ◽  
Robert Cifelli ◽  
Thomas M. Hamill
Keyword(s):  
United States ◽  
Extreme Precipitation ◽  
Southeastern United States ◽  
Warm Season ◽  
Stage Iv ◽  
Flow Patterns ◽  
Water Vapor Transport ◽  
Cool Season ◽  
Extreme Precipitation Events ◽  
Precipitation Events

Abstract This paper documents the characteristics of extreme precipitation events (EPEs) in the southeastern United States (SEUS) during 2002–11. The EPEs are identified by applying an object-based method to 24-h precipitation analyses from the NCEP stage-IV dataset. It is found that EPEs affected the SEUS in all months and occurred most frequently in the western portion of the SEUS during the cool season and in the eastern portion during the warm season. The EPEs associated with tropical cyclones, although less common, tended to be larger in size, more intense, and longer lived than “nontropical” EPEs. Nontropical EPEs in the warm season, relative to those in the cool season, tended to be smaller in size and typically involved more moist, conditionally unstable conditions but weaker dynamical influences. Synoptic-scale composites are constructed for nontropical EPEs stratified by the magnitude of vertically integrated water vapor transport (IVT) to examine distinct scenarios for the occurrence of EPEs. The composite results indicate that “strong IVT” EPEs occur within high-amplitude flow patterns involving strong transport of moist, conditionally unstable air within the warm sector of a cyclone, whereas “weak IVT” EPEs occur within low-amplitude flow patterns featuring weak transport but very moist and conditionally unstable conditions. Finally, verification of deterministic precipitation forecasts from a reforecast dataset based on the NCEP Global Ensemble Forecast System reveals that weak-IVT EPEs were characteristically associated with lower forecast skill than strong-IVT EPEs. Based on these results, it is suggested that further research should be conducted to investigate the forecast challenges associated with EPEs in the SEUS.

scholarly journals The Impact of Weeding Regime, Planting Density, and Growth Habits on Watermelon Yield in an Organic System

2019 ◽  
Vol 29 (5) ◽  
pp. 571-577
Author(s):  
Suzanne P. Stone ◽  
George E. Boyhan ◽  
W. Carroll Johnson
Keyword(s):  
United States ◽  
Weed Control ◽  
Growth Habit ◽  
Southeastern United States ◽  
Weed Suppression ◽  
Planting Density ◽  
Separate Experiment ◽  
Organic System ◽  
Growth Habits ◽  
The Impact

The southeastern United States produces 50% of U.S. conventional watermelon (Citrullus lanatus) but only 7% of U.S. organic watermelon. Weeds are a major threat to watermelon yield in the southeastern United States, and organic weed control is estimated to cost 20-times more than conventional herbicide programs. The objectives of this study were to determine the optimal weed control regime to reduce hand-weeding costs while maintaining yield and to compare the weed suppression of two watermelon types with differing growth habits in an organic system. In 2014 and 2015, watermelon plots were randomly assigned to the following treatments in a factorial arrangement: vine or compact growth habit; 1.0- or 0.5-m in-row spacing; and weekly weed control (kept weed-free by hoeing and hand-pulling weeds) for 0, 4, or 8 weeks after transplanting (WAT). At the time of the watermelon harvest, not weeding resulted in average total weed densities of 86.6 and 87.0 weeds/m2, and weeding for 4 WAT resulted in average total weed densities of 26.4 and 7.0 weeds/m2 in 2014 and 2015, respectively. Nonetheless, weeding for 4 WAT resulted in watermelon yields and fruit counts comparable to those of weeding for 8 WAT during both years. This partial-season weeding regime resulted in 67% and 63% weeding cost reductions for vine and compact plants, respectively, in 2014, and a 43% reduction for both growth habit types in 2015. In 2015, a separate experiment that evaluated weeding regimes that lasted 0, 1, 2, 3, 4, and 8 WAT found that yields resulting from weeding for 3 WAT were greater than those resulting from weeding for 2 WAT. However, the yields did not differ when weeding was performed for 4 WAT and 8 WAT.

Preemergence Weed Control in Southeastern Forest Nurseries

Weed Science ◽  
1973 ◽  
Vol 21 (4) ◽  
pp. 363-366 ◽  
Author(s):  
T. R. Dill ◽  
M. C. Carter
Keyword(s):  
United States ◽  
Pinus Taeda ◽  
Weed Control ◽  
Loblolly Pine ◽  
Southeastern United States ◽  
Pinus Elliottii ◽  
Slash Pine ◽  
High Rate ◽  
Forest Nurseries ◽  
Low Rate

Weed control trials were conducted on loblolly pine (Pinus taedaL.) or slash pine (Pinus elliottiiEngelm.) seedbeds at 12 locations in the southeastern United States. Good weed control was obtained from 2,4-bis-(isopropylamino)-6-(methylthio)-s-triazine (prometryne) at 2.2 and 4.5 kg/ha;N,N-dimethyl-2,2-diphenylacetamide (diphenamid) at 4.5 and 9 kg/ha; α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) at 1.1 and 2.2 kg/ha; and 2-ethylthio-4,6-bis-isopropylamino-s-triazine (GS-16068) at 2.2 and 4.5 kg/ha as preemergence applications immediately followed by irrigation. Diphenamid and trifluralin treatments were not injurious to either pine species at either rate. GS-16068 was only slightly injurious at the high rate at one location. Prometryne was injurious at two locations at the high rate and at one location at the low rate.

scholarly journals Quantifying the Separation of Enhanced ZDR and KDP Regions in Nonsupercell Tornadic Storms

2018 ◽  
Vol 33 (5) ◽  
pp. 1143-1157 ◽  
Author(s):  
Scott D. Loeffler ◽  
Matthew R. Kumjian
Keyword(s):  
United States ◽  
Southeastern United States ◽  
Separation Distance ◽  
Dual Polarization ◽  
Cool Season ◽  
The Public ◽  
Size Sorting ◽  
The Right ◽  
Tornadic Storms ◽  
Differential Reflectivity

Abstract Tornadoes associated with nonsupercell storms present unique challenges for forecasters. These tornadic storms, although often not as violent or deadly as supercells, occur disproportionately during the overnight hours and the cool season—times when the public is more vulnerable. Additionally, there is significantly lower warning skill for these nonsupercell tornadoes compared to supercell tornadoes. This study utilizes dual-polarization Weather Surveillance Radar-1988 Doppler (WSR-88D) data to analyze nonsupercell tornadic storms over a three-and-a-half-year period focused on the mid-Atlantic and southeastern United States. A signature found in a large number of cases is the separation of low-level specific differential phase KDP and differential reflectivity ZDR enhancement regions, thought to arise owing to size sorting. This study employs a new method to define the “separation vector,” which comprises the distance separating the enhancement regions and the direction from the KDP enhancement region to the ZDR enhancement region, measured relative to storm motion. While there is some variation between cases, preliminary results show that the distribution of separation distance between the enhancement regions is centered around 3–4 km and tends to maximize around the time of tornadogenesis. A preferred quadrant for separation direction is found between parallel and 90° to the right of storm motion and is most orthogonal near the time of tornadogenesis. Further, it is shown that, for a given separation distance, separation direction increasing from 0° toward 90° is associated with increased storm-relative helicity.

Postemergence Weed Control with Glyphosate Plus Flumioxazin Combinations

2010 ◽  
Vol 24 (3) ◽  
pp. 356-360 ◽  
Author(s):  
Glenn Wehtje ◽  
Charles H. Gilliam ◽  
Stephen C. Marble
Keyword(s):  
United States ◽  
Weed Control ◽  
Logistic Model ◽  
Southeastern United States ◽  
Cost Effective ◽  
Regression Analyses ◽  
Weed Species ◽  
Control Data ◽  
Nursery Production

Glyphosate plus flumioxazin tank mixtures have become popular in the nursery production and landscape maintenance industries in the southeastern United States. Research was conducted to compare the efficacy of such a mixture relative to the components applied alone. Glyphosate, flumioxazin, and glyphosate plus flumioxazin (2 : 1, w/w) were applied POST in container trials to four weed species at a series of rates that ranged from no effect to death. Regression analyses revealed that control data from all three treatment series could be described by the four-parameter, log-logistic model. With respect to glyphosate and flumioxazin applied alone, analysis revealed that across all four species, a lower rate of flumioxazin was required for 90% control than of glyphosate. The rate of the mixture required for 90% control was generally intermediate to the components applied alone and ranged from 0.36 kg ha−1 for hairy bittercress to 1.52 kg ha−1 for eclipta. Glyphosate alone was more cost effective than either flumioxazin alone or the mixture for the POST-applied control of all four species. The popularity of the tank mixture might be the result of flumioxazin-based PRE activity that was not measured in this study.

scholarly journals Grazing management and supplementation effects on forage and dairy cow performance on cool-season pastures in the southeastern United States

2011 ◽  
Vol 94 (8) ◽  
pp. 3949-3959 ◽  
Author(s):  
B. Macoon ◽  
L.E. Sollenberger ◽  
C.R. Staples ◽  
K.M. Portier ◽  
J.H. Fike ◽  
...  
Keyword(s):  
United States ◽  
Dairy Cow ◽  
Southeastern United States ◽  
Grazing Management ◽  
Cool Season ◽  
Cow Performance
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