scholarly journals Optimization of Herbicide Use: Study on Spreading and Evaporation Characteristics of Glyphosate-Organic Silicone Mixture Droplets on Weed Leaves

Agronomy ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 547 ◽  
Author(s):  
Li ◽  
Travlos ◽  
Qi ◽  
Kanatas ◽  
Wang
Keyword(s):  
Leaf Surface ◽  
Orthogonal Experiment ◽  
Digital Camera ◽  
Weed Species ◽  
Coverage Area ◽  
Binary Images ◽  
Spread Area ◽  
Droplet Sizes ◽  
Groove Structure ◽  
Herbicide Use

Herbicide deposition rate can be affected by the leaf surface features of weeds and have a significant impact on the overall efficacy. In this paper, an orthogonal experiment was conducted to investigate the differences of droplet evaporation and spreading characteristics corresponding to weed leaf surface with hairy, waxy and rough (ridged) structures. Three weed species—Descurainia sophia, Lepidium lotifolium, and Lolium temulentum—were included in the study, representing these three leaf structures respectively. Glyphosate sprays with organic silicone surfactant in different concentrations were composed for the test. Single droplets with two diameters of 0.05 μL and 0.1 μL were deposited on the leaves to evaluate the evaporation and spreading characteristics. A digital camera was used and the evaporation duration and the maximum droplet coverage images could be captured and extracted from the recorded videos. The Image Processing Toolbox in Matlab was applied to segment the images for droplet and leaf background and the binary images’ pixel numbers were counted for coverage area calculation. The results revealed that the evaporation duration was reduced with the increase of the organic silicone concentration, while the spread area was expanded. The droplet spread more widely and evaporated faster on D. sophia leaves than on the leaves with L. lotifolium and L. temulentum surfaces. The spreading area and evaporation duration varied much faster on L. lotifolium leaves than on the leaves of other weed species. The droplet sizes affected spreading more significantly on L. temulentum leaf surface, as the spreading procedure of small size droplets was restrained by the groove structure. The results of this study would benefit the consideration of the farmers when selecting the proper nozzle code and the determining of the surfactant mixture in order to optimize the use of herbicides like glyphosate.

Characterisation of glyphosate uptake into grass species

2003 ◽  
Vol 54 (9) ◽  
pp. 877 ◽  
Author(s):  
Z. Q. Liu
Keyword(s):  
Leaf Surface ◽  
Current Knowledge ◽  
Grass Species ◽  
Droplet Spreading ◽  
Barnyard Grass ◽  
Spread Area ◽  
Per Se ◽  
High Level ◽  
Content Range ◽  
Determining Factor

The effect of surfactant ethylene oxide (EO) content, droplet spread area, and the active ingredient (a.i.) dose on the leaf surface on glyphosate uptake into 3 grass species (wheat, ryegrass, and barnyard grass) was investigated. It was found that glyphosate uptake into wheat was only moderately correlated (R2 = 0.66) with surfactant EO content (range 5–20 units per molecule). By contrast, a highly negative correlation (R2 = 0.98) was found between the uptake and the spread area of the treatment formulations on the leaf surface. The influence of droplet spreading on glyphosate uptake was further investigated using a super-spreading surfactant, Silwet L-77, and varying a.i. concentrations. It was demonstrated that the determining factor for glyphosate uptake into all 3 grass species was the a.i. dose (in μg/mm2) formed on the leaf surface after droplet spreading. Droplet spread area per se had only an indirect effect on the uptake through diluting the a.i. dose. In the presence of a non-spreading surfactant, Mon 0818, glyphosate uptake depended not only on the a.i. dose but also the surfactant dose on the leaf surface. In the absence of surfactants, high a.i. dose alone was not enough to ensure a high level uptake. The results are discussed in relation to the current knowledge on the interactions between surfactants and herbicide uptake.

scholarly journals Season-long weed control with sequential herbicide programs in California tree nut crops

2020 ◽  
Vol 34 (6) ◽  
pp. 834-842
Author(s):  
Caio A. C. G. Brunharo ◽  
Seth Watkins ◽  
Bradley D. Hanson
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Control Program ◽  
Early Spring ◽  
High Rate ◽  
Weed Species ◽  
Tree Nut ◽  
Herbicide Use ◽  
Herbicide Programs ◽  
Grass Weed

AbstractWeed control in tree nut orchards is a year-round challenge for growers that is particularly intense during winter through summer as a result of competition and interference with management and harvest operations. A common weed control program consists of an application of a winter PRE and POST herbicide mixture, followed by a desiccation treatment in early spring and before harvest. Because most spring and summer treatments depend on a limited number of foliar-applied herbicides, summer-germinating species and/or herbicide-resistant biotypes become troublesome. Previous research has established effective PRE herbicide programs targeting winter glyphosate-resistant weeds. However, more recently, growers have reported difficulties in controlling several summer-germinating grass weeds with documented or suspected resistance to the spring and summer POST herbicide programs. In this context, research was conducted to evaluate a sequential PRE approach to control winter- and summer-germinating orchard weeds. Eight field experiments were conducted in tree nut orchards to evaluate the efficacy of common winter herbicide programs and a sequential herbicide program for control of a key summer grass weed species. In the sequential-application strategy, three foundational herbicide programs applied in the winter were either mixed with pendimethalin, followed with pendimethalin in March, or applied as a split application of pendimethalin in both winter and spring. Results indicate that the addition of pendimethalin enhanced summer grass weed control throughout the crop growing season by up to 31%. Applying all or part of the pendimethalin in the spring improved control of the summer grass weed junglerice by up to 49%. The lower rate of pendimethalin applied in the spring performed as well as the high rate in the winter, suggesting opportunities for reducing herbicide inputs. Tailoring sequential herbicide programs to address specific weed challenges can be a viable strategy for improving orchard weed control without increasing herbicide use in some situations.

Analysis Methods for Vessel Generated Spray

2010 ◽  
Author(s):  
Anne M. Fullerton ◽  
Thomas C. Fu ◽  
David A. Drazen ◽  
Don C. Walker
Keyword(s):  
Feature Tracking ◽  
High Speed ◽  
Image Processing Technique ◽  
Inversion Method ◽  
Image Statistics ◽  
Tracking Method ◽  
Binary Images ◽  
Specific Intensity ◽  
Analysis Methods ◽  
Droplet Sizes

The droplet sizes and velocities contained in vessel generated spray are difficult to quantify. This paper describes three different methods to quantify velocity and size distributions from high speed video of spray from a planing boat. These methods include feature tracking, displacement tracking and video inversion. For the feature tracking method, the images were preprocessed using contrast limited adaptive histogram equalization, and then converted to binary images with a specific intensity cutoff level. Image statistics were then generated from this image, including droplet area and effective diameter. These images were processed using commercial PIV software to obtain velocities. For the displacement tracking method, the images were also converted to binary images with a specific intensity cutoff level. Image statistics were again compiled from this binary image. A droplet filter was then applied using a binary erosion image processing technique, where large droplets were removed because the entire droplet may not be in frame, and small droplets were removed because they might not overlap between frames. Droplets were then tracked by comparing the bounding boxes of two droplets between time frames. The video inversion method consisted of the manipulating the original high speed videos from spatial x-y frames in time space to time-y frames in x-space, where the x-axis is longitudinally along the ship and the y axis is vertical to the ship. From this orientation, the speed of the general spray mass could be determined by summing the pixels in time columns for each × frame. Comparisons of droplet size distribution between the feature and displacement tracking method yield qualitatively similar results, with some disagreement likely due to the different threshold levels. The trend of the distribution curve suggests that both methods are unable to resolve the smallest droplet sizes, due to the processing filters applied as well as the field of view of the camera. The three analysis methods compare well in their spray velocity computation, and are also similar to spray speed predictions found in the literature for a given geometry and vessel speed.

Investigating the Wettability of Rapeseed Leaves

2021 ◽  
Vol 37 (3) ◽  
pp. 399-409
Author(s):  
Yong He ◽  
Jianjian Wu ◽  
Shupei Xiao ◽  
Hui Fang ◽  
Qishuai Zheng
Keyword(s):  
Surface Tension ◽  
Free Energy ◽  
Significant Influence ◽  
Leaf Surface ◽  
Contact Angles ◽  
List Type ◽  
Factors Affecting ◽  
Spray Droplets ◽  
Droplet Sizes ◽  
Leaf Wettability

HighlightsContact angles of spray droplets were positively correlated with their surface tension.Wettability of rape leaves was generally poor for most pesticides.Surface structure and free energy determine the hydrophobicity of rape leaves.The size of the spray droplets had no significant influence on rape leaf wettability.Abstract. In order to improve the deposition and adherence of spray droplets on leaf surfaces, the wettability of rapeseed leaves was investigated. We explored the effect of different pesticides and test surfaces on droplet contact angles, and analyzed the effects of leaf surface properties, droplet sizes and the addition of organosilicone adjuvant on wettability. The results indicated that contact angles of different liquids were positively correlated with their surface tension for rapeseed leaves. The wettability of rapeseed leaves was generally poor using different pesticides, but was highest for a fungicide mixture of difenoconazole and propiconazole. The hydrophobicity of rapeseed leaves is largely determined by the complex microstructure and the low surface free energy of the leaves. The size of the spray droplets had no significant influence on the wettability. Moreover, the addition of an organosilicone adjuvant significantly reduced the surface tension of all spray droplets, with the best result for a 50% procymidone solution. In conclusion, the factors affecting rapeseed leaf surface wettability should be considered comprehensively before selecting the appropriate pesticide, so as to improve its utilization rates. Keywords: Contact angle, Leaf surface, Pesticide application, Spray droplet.

Annual broadleaf crop frequency and residual weed populations in Saskatchewan Parkland

Weed Science ◽  
1999 ◽  
Vol 47 (2) ◽  
pp. 208-214 ◽  
Author(s):  
F. Craig Stevenson ◽  
Adrian M. Johnston
Keyword(s):  
Reproductive Strategies ◽  
Cereal Crops ◽  
Wild Oat ◽  
Weed Species ◽  
Weed Density ◽  
Future Problem ◽  
Weed Infestation ◽  
The Difference ◽  
A Site ◽  
Herbicide Use

The development of problematic weed populations is a concern in western Canadian fields where canola and pea are grown in a 4-yr sequence with spring cereal grains. Weed densities were examined at a site near Melfort, Saskatchewan, Canada, from 1994 to 1997 in seven zero-till managed crop rotations. Four rotations that included canola, pea, or flax in at least 3 of 4 yr (HBF: high broadleaf–crop frequency) were compared with three rotations that included broadleaf crops grown in 2 of 4 yr (LBF: low broadleaf–crop frequency). Spring wheat and barley were the cereal crops in rotation. Residual (postherbicide application) weed density for each weed species in a given year was summed across all phases for each rotation to reflect the overall weed infestation. Four annual broadleaf weed species were most abundant in 1996 and a second group of three species, having a variety of reproductive strategies, became progressively less abundant as the study progressed. The difference between the HBF and LBF rotations for the density of these species varied and was most prominent in years when environmental conditions were conducive for their growth. More frequent applications of ethafluralin, with its residual weed control, best explained why wild oat and catchweed bedstraw generally were less abundant in the HBF rotations. Of particular interest was the 8 plants m−-2greater density of dandelion and perennial sowthistle in the HBF vs. LBF rotations in the last year of the study. It is thought that the limited herbicide options for the control of these species could present a future problem if they continued to develop in the HBF rotations. Differences in herbicide use between the HBF and LBF rotations were considered the primary factor controlling the rotation effects on weed density.

scholarly journals Targeting Weed Seeds In-Crop: A New Weed Control Paradigm for Global Agriculture

2013 ◽  
Vol 27 (3) ◽  
pp. 431-436 ◽  
Author(s):  
Michael Walsh ◽  
Peter Newman ◽  
Stephen Powles
Keyword(s):  
Weed Control ◽  
Control Strategies ◽  
Weed Seed ◽  
Weed Species ◽  
New Paradigm ◽  
Control Paradigm ◽  
Weed Seeds ◽  
Global Agriculture ◽  
Annual Weeds ◽  
Herbicide Use

The widespread evolution of multiple herbicide resistance in the most serious annual weeds infesting Australian cropping fields has forced the development of alternative, non-chemical weed control strategies, especially new techniques at grain harvest. Harvest weed seed control (HWSC) systems target weed seed during commercial grain harvest operations and act to minimize fresh seed inputs to the seedbank. These systems exploit two key biological weaknesses of targeted annual weed species: seed retention at maturity and a short-lived seedbank. HWSC systems, including chaff carts, narrow windrow burning, bale direct, and the Harrington Seed Destructor, target the weed seed bearing chaff material during commercial grain harvest. The destruction of these weed seeds at or after grain harvest facilitates weed seedbank decline, and when combined with conventional herbicide use, can drive weed populations to very low levels. Very low weed populations are key to sustainability of weed control practices. Here we introduce HWSC as a new paradigm for global agriculture and discuss how these techniques have aided Australian grain cropping and their potential utility in global agriculture.

The Selective Memory of Weed Seedbanks after 18 Years of Conservation Tillage

Weed Science ◽  
2011 ◽  
Vol 59 (1) ◽  
pp. 98-106 ◽  
Author(s):  
Anne Légère ◽  
F. Craig Stevenson ◽  
Diane L. Benoit
Keyword(s):  
Crop Rotation ◽  
Weed Management ◽  
Conservation Tillage ◽  
Red Clover ◽  
Seed Rain ◽  
Crop Rotations ◽  
Residual Effects ◽  
Weed Species ◽  
Emergence Patterns ◽  
Herbicide Use

A conservation tillage study provided the opportunity to test whether tillage effects on the germinable weed seedbank would be consistent across different crop rotations and to investigate the potential residual effects of herbicide treatments terminated 12 yr earlier. Our objective was to measure the effects of tillage (moldboard plow [MP] vs. chisel plow [CP] vs. no-till [NT]), crop rotation (2-yr barley–red clover followed by 4-yr barley–canola–wheat–soybean rotation, compared to a cereal monoculture), and of a prior weed management factor (three intensity levels of herbicide use) on the density, diversity, and community structure of weed seedbanks. Species richness, evenness (Shannon'sE), and diversity (Shannon'sH′) of spring seedbanks varied little across treatments and over time. Total seedbank density generally increased as tillage was reduced, with some variations due to weed management in 1993 and crop rotation in 2006. Crop rotations generally had smaller seedbanks with fewer species than the monoculture. In 1993, seedbanks with minimum weed management were twice as dense as those with intensive or moderate weed management (approximately 6,000 vs. 3,000 seed m−2). By 2006, seed density averaged 6,838 seed m−2across intensive and moderate weed management regardless of tillage, but was nearly twice as large in NT (12,188 seed m−2) compared to MP (4,770 seed m−2) and CP (7,117 seed m−2) with minimum weed management (LSD0.005= 4488). Species with abundant seedbanks responded differently to treatments. Barnyardgrass and green foxtail had larger seedbanks in the monoculture than in the rotation. Common lambsquarters and pigweed species had large seedbanks in tilled treatments in the rotation, whereas yellow foxtail and field pennycress contributed to the large seedbanks observed in NT treatments. The latter two species were also associated with residual effects of weed management treatments (terminated 12 yr earlier) in NT. The differential seedbank response of weed species, attributed in part to contrasting weed emergence patterns and agronomic practice effects on seed rain, explained some of the weak treatment effects observed for total seedbank density and diversity. The large weed seedbanks observed in NT plots after 18 yr confirms the importance of seed rain and seedbank management for the sustainability of NT systems.

scholarly journals Landscape dynamics of Paspalum quadrifarium grasslands analyzed by Morphological Spatial Pattern Analysis (MSPA)

2018 ◽  
Author(s):  
Marcelo L Gandini ◽  
Bruno D Lara ◽  
Laura Beatriz Moreno ◽  
Maria A Cañibano ◽  
Patricia A Gandini
Keyword(s):  
Spatial Pattern ◽  
Management Practices ◽  
Pattern Analysis ◽  
Central Area ◽  
Wide Distribution ◽  
Spatial Pattern Analysis ◽  
Percentage Increase ◽  
Coverage Area ◽  
Binary Images ◽  
Morphological Spatial Pattern Analysis

Background. Despite its wide distribution worldwide, only 4.6% of temperate grasslands are included within systems of protected areas. In Argentina, this situation is even more alarming: only 1.05% is protected. The study area (central area of the southern Salado River basin) has a large extent of grasslands of Paspalum quadrifarium (Pq) which has been target since the last century of a variety of agricultural management practices including fire burning for cattle grazing. Methods. Binary images of presence-absence data of Pq from a 42-year (1974-2016) land cover change study were used as base data. MSPA (Morphological Spatial Pattern Analysis) and Network Analysis were performed to the data using Guidos Toolbox for the estimation of habitat and connectivity dynamics of the Pq patches (fragments). Results. A loss of the coverage area and habitat nuclei of this grassland was observed between the beginning and the end of the study period. A drastic reduction in connectivity was also evident in resulting maps. The number of large Pq grassland fragments (> 50 ha) decreased during the study period, and fragmentation measured as number of components (patches) was higher at the end of study period. The Pq pajonal nuclei had their minimum representativeness in 2000, and recovered slightly in 2011, but with a significant percentage increase of the small patches (=islets) and linear elements as bridges and branches. Large corridors (mainly edge of roads) could be observed at the end of study period, while the total connectivity of the landscape pattern drops abruptly. Discussion. The habitat reduction could have an impact on the ecosystem functioning and the mobility of some species of native fauna. The connecting elements of the landscape were maintained and/or recovered in percentage in 2011 and 2016. This fact, although favoring the dispersion of the present diversity in the habitat nuclei could cause degradation by an edge effect. On the methodological side, the use of a proved tool as Guidos Toolbox for evaluating forest fragmentation could also be useful for monitoring dynamics of a grassland-habitat fragmentation.

Weed Seed Population Response to Tillage and Herbicide Use in Three Irrigated Cropping Sequences

Weed Science ◽  
1990 ◽  
Vol 38 (6) ◽  
pp. 511-517 ◽  
Author(s):  
Daniel A. Ball ◽  
Stephen D. Miller
Keyword(s):  
Seed Bank ◽  
Soil Seed Bank ◽  
Weed Seed ◽  
Weed Species ◽  
Pronounced Increase ◽  
Common Lambsquarters ◽  
Hairy Nightshade ◽  
Redroot Pigweed ◽  
Cropping Sequence ◽  
Herbicide Use

Research was conducted to evaluate the effects of primary tillage (moldboard plowing and chisel plowing), secondary tillage (row cultivation), and herbicides on weed species changes in the soil seed bank in three irrigated row cropping sequences over a 3-yr period. The cropping sequences consisted of continuous corn for 3 yr (CN), continuous pinto beans for 3 yr (PB), and sugarbeets for 2 yr followed by corn in the third year (SB). A comparison between moldboard and chisel plowing indicated that weed seed were more prevalent near the soil surface after chisel plowing. The density of certain annual weed seed over the 3-yr period increased more rapidly in the seed bank after chisel plowing compared to moldboard plowing. Species exhibiting the most pronounced increase included hairy nightshade and stinkgrass in the PB cropping sequence and redroot pigweed and common lambsquarters in the SB sequence. Conversely, kochia seed density in the SB sequence decreased more rapidly in chisel-plowed plots. Row cultivation generally reduced seed bank densities of most species compared to uncultivated plots. Herbicide use in each cropping sequence produced a shift in the weed seed bank in favor of species less susceptible to applied herbicides. In particular, seed of hairy nightshade became prevalent in the PB cropping sequence, and seed of kochia, redroot pigweed, and common lambsquarters became prevalent in the SB sequence.

scholarly journals Weed Flora of Vineyards in Diyarbakır Province, Turkey

2020 ◽  
Author(s):  
Cumali Özaslan ◽  
Esmanur Pekcan Kaçar
Keyword(s):  
Weed Management ◽  
Cynodon Dactylon ◽  
Management Strategies ◽  
Hordeum Spontaneum ◽  
Weed Species ◽  
Coverage Area ◽  
Avena Sterilis ◽  
Important Place ◽  
Alopecurus Myosuroides ◽  
Weed Flora

Background: Viticulture occupies an important place in agricultural production of Diyarbakır province, Turkey. However, weeds significantly impair the productivity of vineyards in the province. The knowledge of weed flora of a particular region is crucial to develop region-specific weed management strategies. Methods: This study was carried out to determine the weed species, their densities and frequency of occurrence in 78 vineyards of 13 districts in Diyarbakır province. Exploratory surveys were conducted to record the occurrence, density and coverage area of weed species. A 1×1 m quadrate was used, which was randomly placed in vineyards and weed species falling within the quadrate were noted. Result: A total 165 weed species and 128 taxa belonging to 35 botanical families (1 parasitic, 16 monocotyledons and 18 dicotyledons) were identified from the surveyed area. The weed species’ density over the whole province was 91 weeds m-2. Avena sterilis L. was the most widespread weed with the highest density (9.93 plants m-2) in the surveyed area followed by Fumaria asepale Boiss. (7.18), Galium tricornutum (4.85), Ranunculus arvensis (3.82), Silene aegyptiaca (3.70), Bromus sterilis (3.64) Lamium purpureum (3.58), Hordeum spontaneum (3.35), Anthemis sp. (3.07), Crepis alpina (2.94), Thlaspi perfoliatum (2.91), Alopecurus myosuroides (2.81), Bongardia chrysogonum (2.80), Scandix pecten-veneris (2.24), Cynodon dactylon (1.71), Hypecoum procumbens (1.69), Lolium perenne (1.41), Sorghum halepense (1.33), Sinapis arvensis (1.24), Buglossoides arvense (1.22), Daucus carota (1.21), Trifolium nigrescens (1.21), Vicia hybrida (1.05), Senecio vernalis (1.04) and Ornithogalum narbonense (1.02). The most prevalent weed were L. purpureum (66.68%), Papaver sp. (66.49%), S. vernalis (65.82%), Anthemis sp. (65.10%), A. sterilis (63.07%), R. arvensis (60.44%), Convolvulus arvensis (56.76%), Carduus pycnocephalus (55.79%), G. tricornutum (55.43%), Fumaria asepale (55.05%), Crepis alpina (54.08%), Thlaspi perfoliatum (51.95%) and S. arvensis (51.04%).

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