Sugarcane response and fall panicum (Panicum dichotomiflorum) control with topramezone and triazine herbicides

2019 ◽  
Vol 34 (2) ◽  
pp. 241-249
Author(s):  
Raphael M. Negrisoli ◽  
D. Calvin Odero ◽  
Gregory E. MacDonald ◽  
Brent A. Sellers ◽  
H. Dail Laughinghouse
Keyword(s):  
Chlorophyll Fluorescence ◽  
Field Studies ◽  
Organic Soils ◽  
Canopy Closure ◽  
Total Chlorophyll ◽  
Triazine Herbicides ◽  
Variable Fluorescence ◽  
Meristematic Tissue ◽  
Sugarcane Yield ◽  
Panicum Dichotomiflorum

AbstractField studies were conducted on organic soils in Belle Glade, FL, in 2016 to 2017 to evaluate sugarcane tolerance and fall panicum control with topramezone applied alone or in combination with triazine herbicides (atrazine, metribuzin, ametryn). Treatments included topramezone (25 and 50 g ai ha−1) applied alone or in combination with atrazine (2,240 g ai ha−1), metribuzin (2,240 g ai ha−1), and ametryn (440 g ha−1) on four plant cane varieties to evaluate tolerance, and on second ratoon fields to determine efficacy on fall panicum control. Topramezone applied alone had no effect on sugarcane chlorophyll fluorescence (i.e., the ratio of variable fluorescence to maximum fluorescence), total chlorophyll, and carotenoid 7 to 28 d after treatment (DAT), suggesting sugarcane tolerance. Significant reduction of these parameters occured 7 to 14 DAT when topramezone (50 g ai ha−1) was applied with ametryn or metribuzin; however, reductions were not detected thereafter, indicating recovery. Sugarcane yield was not affected by topramezone applied alone or in combination with the triazine herbicides. Topramezone (50 g ai ha−1) plus metribuzin resulted in acceptable control of fall panicum (84%) with limited to no regrowth of meristematic tissue at sugarcane canopy closure, equivalent to 56 to 70 DAT. These results indicate that when sequential applications of topramezone, applied alone or in combination with these triazine herbicides, are required for efficacious weed control, topramezone applications alone can be made after 7 d, whereas the combinations can be made after 14 or 21 d, depending on sugarcane sensitivity.

A biosensor for triazine herbicides based on chlorophyll fluorescence in photosystem 2

1992 ◽  
pp. 550 ◽  
Author(s):  
D.A. Moss ◽  
S. Brauer ◽  
J. Reichert ◽  
W. Mäntele ◽  
H.J. Ache
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosystem 2 ◽  
Triazine Herbicides

Field dissipation of S-metolachlor in organic and mineral soils used for sugarcane production in Florida

2019 ◽  
Vol 34 (3) ◽  
pp. 362-370
Author(s):  
Jose V. Fernandez ◽  
D. Calvin Odero ◽  
Gregory E. MacDonald ◽  
Jason A. Ferrell ◽  
Brent A. Sellers ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Moisture ◽  
Linear Trend ◽  
Organic Matter Content ◽  
Field Studies ◽  
Matter Content ◽  
Organic Soils ◽  
Sugarcane Production ◽  
Mineral Soils ◽  
Moisture Conditions

AbstractDissipation of S-metolachlor, a soil-applied herbicide, on organic and mineral soils used for sugarcane production in Florida was evaluated using field studies in 2013 to 2016. S-metolachlor was applied PRE at 2,270 g ha−1 on organic and mineral soils with 75% and 1.6% organic matter, respectively. The rate of dissipation of S-metolachlor was rapid on mineral soils compared with organic soils. Dissipation of S-metolachlor on organic soils followed a negative linear trend resulting in half-lives (DT50) ranging from 50 to 126 d. S-metolachlor loss on organic soils was more rapid under high soil-moisture conditions than in corresponding low soil-moisture conditions. On mineral soils, dissipation of S-metolachlor followed an exponential decline. The DT50 of S-metolachlor on mineral soils ranged from 12 to 24 d. The short persistence of S-metolachlor on mineral soils was likely attributed to low organic matter content with limited adsorptive capability. The results indicate that organic matter content and soil moisture are important for persistence of S-metolachlor on organic and mineral soils used for sugarcane production in Florida.

Field Dissipation of Atrazine and Metribuzin in Organic Soils in Florida

2014 ◽  
Vol 28 (4) ◽  
pp. 578-586 ◽  
Author(s):  
Dennis C. Odero ◽  
Dale L. Shaner
Keyword(s):  
Weed Control ◽  
Residual Activity ◽  
Field Studies ◽  
South Florida ◽  
Field Conditions ◽  
Agricultural Area ◽  
Organic Soils ◽  
Bioavailable Fraction ◽  
Rate Of Dissipation ◽  
Atrazine Degradation

Sugarcane growers have observed reduced residual activity of atrazine on organic soils in the Everglades Agricultural Area (EAA) of south Florida. Field studies were conducted between 2011 and 2012 to determine the rate of dissipation of atrazine at 2.24, 4.48, and 8.96 kg ha−1and metribuzin at 0.56, 1.12, and 2.24 kg ha−1in the top 10 cm of soil in sugarcane fields in the EAA. The bioavailable fraction of atrazine dissipated more rapidly than the total amount of atrazine in the soil. Half-lives of the total and bioavailable fraction of atrazine ranged between 3.9 to 12.1 d and 1.0 to 7.5 d, respectively. Metribuzin dissipated much more slowly than atrazine on organic soils. Similarly, dissipation of the bioavailable fraction of metribuzin was more rapid than was the dissipation of the total amount of metribuzin in the soil. Half-lives of the total and bioavailable fraction of metribuzin ranged between 16.2 and 24.8 d and 6.0 and 14.3 d, respectively. These results indicate that enhanced atrazine degradation occurs on organic soils under field conditions in the EAA, resulting in shorter residual atrazine activity. This implies that metribuzin is a better option for weed control in sugarcane grown on organic soils of the EAA exhibiting enhanced atrazine degradation.

scholarly journals Irradiance and nutrient-dependent effects on photosynthetic electron transport in Arctic phytoplankton: A comparison of two chlorophyll fluorescence-based approaches to derive primary photochemistry

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0256410
Author(s):  
Yayla Sezginer ◽  
David J. Suggett ◽  
Robert W. Izett ◽  
Philippe D. Tortell
Keyword(s):  
Chlorophyll Fluorescence ◽  
Electron Transport ◽  
Electron Transport Rate ◽  
Photochemical Efficiency ◽  
Photosynthetic Electron Transport ◽  
Marine Phytoplankton ◽  
Transport Rate ◽  
Variable Fluorescence ◽  
Primary Photochemistry ◽  
Electron Transport Rates

We employed Fast Repetition Rate fluorometry for high-resolution mapping of marine phytoplankton photophysiology and primary photochemistry in the Lancaster Sound and Barrow Strait regions of the Canadian Arctic Archipelago in the summer of 2019. Continuous ship-board analysis of chlorophyll a variable fluorescence demonstrated relatively low photochemical efficiency over most of the cruise-track, with the exception of localized regions within Barrow Strait, where there was increased vertical mixing and proximity to land-based nutrient sources. Along the full transect, we observed strong non-photochemical quenching of chlorophyll fluorescence, with relaxation times longer than the 5-minute period used for dark acclimation. Such long-term quenching effects complicate continuous underway acquisition of fluorescence amplitude-based estimates of photosynthetic electron transport rates, which rely on dark acclimation of samples. As an alternative, we employed a new algorithm to derive electron transport rates based on analysis of fluorescence relaxation kinetics, which does not require dark acclimation. Direct comparison of kinetics- and amplitude-based electron transport rate measurements demonstrated that kinetic-based estimates were, on average, 2-fold higher than amplitude-based values. The magnitude of decoupling between the two electron transport rate estimates increased in association with photophysiological diagnostics of nutrient stress. Discrepancies between electron transport rate estimates likely resulted from the use of different photophysiological parameters to derive the kinetics- and amplitude-based algorithms, and choice of numerical model used to fit variable fluorescence curves and analyze fluorescence kinetics under actinic light. Our results highlight environmental and methodological influences on fluorescence-based photochemistry estimates, and prompt discussion of best-practices for future underway fluorescence-based efforts to monitor phytoplankton photosynthesis.

scholarly journals Will UK peatland restoration reduce dissolved organic matter concentrations in upland drinking water supplies?

2020 ◽  
Author(s):  
Jennifer Williamson ◽  
Christopher Evans ◽  
Bryan Spears ◽  
Amy Pickard ◽  
Pippa J. Chapman ◽  
...  
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Field Studies ◽  
Organic Soils ◽  
Catchment Management ◽  
Raw Water ◽  
Considerable Uncertainty ◽  
Published Evidence ◽  
Peatland Restoration

Abstract. Rising dissolved organic matter (DOM) concentrations, and associated increases in water colour, have posed a potential problem for the UK water industry since the phenomenon was first reported in the early 1990s. Elevated DOM concentrations in raw water are of particular concern in upland catchments dominated by organic soils where DOM production tends to be highest. In recent years, water companies have considered the capacity for catchment interventions to improve raw water quality at source, relieving the need for costly and complex engineering solutions in treatment works, but there is considerable uncertainty around the effectiveness of these measures. One of the primary evidence gaps is the extent to which catchment management is capable of influencing DOM concentrations at the point of abstraction, field studies rarely extending beyond sub-catchment or stream scale. Our review of the published evidence suggests that catchment management could make a contribution to mitigating recent DOM increases in some circumstances, particularly where plantation forestry has been grown on peat, and where control of nutrients in runoff could reduce in-reservoir DOM production. Evidence for the efficacy of most other measures that target reductions in DOM loading for catchment to reservoir remains insufficient to support wider scale application. Collectively, these measures have the potential to reduce DOM concentrations in drinking water reservoirs but they must be selected on a site-specific basis, where the scale, effect size and duration of the catchment intervention are considered in relation to both the treatment capacity of the works and future projected DOM trends.

Comparison of Chlorophyll Fluorescence and Fresh Weight as Herbicide Bioassay Techniques

Weed Science ◽  
1985 ◽  
Vol 33 (1) ◽  
pp. 29-33 ◽  
Author(s):  
David R. Shaw ◽  
Thomas F. Peeper ◽  
D. L. Nofziger
Keyword(s):  
Chlorophyll Fluorescence ◽  
Avena Sativa ◽  
Inflection Point ◽  
Plant Size ◽  
Variable Fluorescence ◽  
Fresh Weight ◽  
Reliable Technique ◽  
Treated Soil ◽  
Fluorescence Maximum

The sensitivities of chlorophyll fluorescence and fresh weight as bioassay techniques for the determination of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5 (4H)-one], diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea], and atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] concentrations in soil were compared. The ratio of the initial inflection point (I) to the variable fluorescence maximum (P) of intact oat (Avena sativaL. ‘Chilocco’) leaves was determined for plants seeded directly into herbicide-treated soil and for those transplanted into treated soil after 14 days of growth in nutrient solution. Using the chlorophyll fluorescence of transplanted oats bioassay, 0-, 0.13-, 0.25-, and 0.50-ppm concentrations could be distinguished from one another within 8 h for metribuzin, within 24 h for diuron, and within 48 h for atrazine. These distinctions between rates could not be made 17 days after seeding into treated soil when using fresh weight as the bioassay indicator. Chlorophyll fluorescence of oats seeded directly into treated soil was also a reliable technique, but required much more time to attain sufficient plant size for convenient chlorophyll fluorescence determinations.

Invivo chlorophyll fluorescence as a possible indicator of the dormancy stage in Douglas-fir seedlings

1985 ◽  
Vol 15 (4) ◽  
pp. 607-612 ◽  
Author(s):  
C. D. B. Hawkins ◽  
G. R. Lister
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosynthetic Pigment ◽  
Maximum Growth ◽  
Relative Increase ◽  
Douglas Fir ◽  
Fluorescence Induction ◽  
Chlorophyll B ◽  
Total Chlorophyll ◽  
Fluorescence Parameters ◽  
Pigment Contents

Invivo chlorophyll fluorescence and photosynthetic pigment contents of current-year needles from five populations of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco, var. menziesii Franco and var. glauca (Beissn.) Franco) were monitored at 3- to 4-week intervals over 2 years. The results were compared with the reported stage of seedling dormancy to ascertain whether this technique would be suitable for indicating dormancy status. Minimum values of fluorescence-induction parameters, indicating winter photosynthetic inactivation, were observed during the coldest period. The lower the temperature and the greater the irradiance, the greater the apparent inactivation. An increase in chlorophyll a to chlorophyll b ratios and a decrease in total chlorophyll to carotenoid ratios, indicating a relative increase in protective carotene pigments, was associated with this period. Maximum values for the fluorescence parameters were observed during periods of maximum growth. It appears that a rapid and inexpensive means of screening for Douglas-fir's dormancy status could be developed using invivo chlorophyll fluorescence analyses.

scholarly journals The effect of storage temperature of cucumber fruit on chlorophyll fluorescence

2013 ◽  
Vol 53 (1) ◽  
pp. 57-64
Author(s):  
Ryszard Kosson
Keyword(s):  
Chlorophyll Fluorescence ◽  
Storage Temperature ◽  
Optimum Level ◽  
Variable Fluorescence ◽  
Fluorescence Measurements ◽  
Cucumber Fruit ◽  
Variable Chlorophyll Fluorescence ◽  
Relative Variable ◽  
Temperature Levels ◽  
Relative Variable Fluorescence

The effect of three storage temperature levels: 12,5°C, 20°C, and 1,5°C on basic indexes of chlorophyll fluorescence of cucumber fruits was studied. The greenhouse grown cucumber fruits cv. Wiktor F1 were stored in perforated polyethylene bags or without packages. The minimum chlorophyll fluorescence (Fo), maximum chlorophyll fluorescence (Fm), variable chlorophyll fluorescence (Fv) and relative variable fluorescence (Fv/Fm) of the cucumber peel were measured. Relative variable fluorescence was decTeasing when cucumbers were stored at temperature lower or higher than optimum level. The chlorophyll fluorescence measurements can be helpful for determination of appropriate temperature parameters of cucumber storage.

scholarly journals Chlorophyll Fluorescence, Photosynthesis and Growth of Tomato Plants as Affected by Long-Term Oxygen Root Zone Deprivation and Grafting

Agronomy ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 137 ◽  
Author(s):  
Rosario Paolo Mauro ◽  
Michele Agnello ◽  
Miriam Distefano ◽  
Leo Sabatino ◽  
Alberto San Bautista Primo ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Plant Growth ◽  
Root Zone ◽  
Variable Fluorescence ◽  
Cherry Tomato ◽  
Tomato Plants ◽  
Hydroponic System ◽  
Root Hypoxia ◽  
Quantum Yield Of Psii

A greenhouse experiment was conducted to study the effects of the O2 root zone level and grafting on chlorophyll fluorescence, photosynthesis and growth of cherry tomato grown in a hydroponic system. Two O2 concentrations in the root zone, namely Ox (saturation level) and Ox- (2–3 mg L−1), were applied for 30 days on self-grafted cherry tomato Dreamer or grafted onto the hybrids Arnold, Beaufort, Maxifort and Top Pittam. Root hypoxia increased minimum fluorescence (by 10%) while it decreased variable fluorescence and the maximum quantum yield of PSII (up to 16 and 8%, respectively). Moreover, it reduced leaf photosynthesis, transpiration and stomatal conductance (by 12, 17 and 13%, respectively), whereas it increased leaf electrolyte leakage (by 2.1%). The graft combinations showed a different ability in buffering the effects of root hypoxia on plant growth and related components, and these differences were related to their root biomass. The minimum fluorescence was negatively correlated to plant growth, so it may be a useful indicator to select tolerant rootstocks to root hypoxia. Our results suggest the occurrence of both diffusive and metabolic constraints to tomato photosynthesis under root hypoxia, a condition that can be mitigated by selecting rootstocks with a more developed root system.

Residual Effect of 2,4-D on Whole-Stalk– and Billet-Planted Sugarcane

2004 ◽  
Vol 18 (2) ◽  
pp. 304-309 ◽  
Author(s):  
Jonathan D. Siebert ◽  
James L. Griffin ◽  
Curtis A. Jones
Keyword(s):  
Foliar Application ◽  
Residual Effect ◽  
Field Studies ◽  
First Year ◽  
Herbicide Application ◽  
Growing Seasons ◽  
Planting Methods ◽  
Sugarcane Yield ◽  
Shoot Emergence ◽  
Planting System

Field studies conducted for two growing seasons evaluated the effect of 2,4-D applied at 1.6 kg ai/ha to ‘LCP 85-384’ sugarcane 7, 5, 3, and 1 wk before planting (WBP). Sugarcane was planted in mid September using both whole stalks and billet (45 cm) stem sections. When 2,4-D was applied 5 wk or closer to planting, sugarcane shoot emergence and population averaged across planting methods and years were reduced up to 28 wk after planting (WAP) relative to the nontreated control. By 52 WAP, sugarcane had compensated and stalk population was equivalent among treatments. Sugarcane height in response to 2,4-D varied between years, and only in 2001 at 52 WAP was a height reduction observed when 2,4-D was applied 1, 3, or 5 WBP. Crop injury in 2001 was further reflected in reduced sugarcane yield (at least 11%) and sugar yield (at least 12%) more than 1 yr after 2,4-D had been applied 5 wk or closer to harvest of sugarcane for seed. Sugarcane and sugar yields were equivalent for the nontreated control and the 7 WBP 2,4-D treatment in 2001, but 2,4-D application in 2002 did not negatively affect yield. Even though sugarcane shoot populations across the growing seasons were consistently higher for the billet planting system, yields averaged across 2,4-D application timings were greater for billets (18%) compared with whole stalks only for the first year. Because 2,4-D can have a residual effect on sugarcane yield more than 1 yr after the initial foliar application, a 7-wk period should be allowed between herbicide application and harvest of LCP 85-384 for billet or whole-stalk planting.

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