Effects of Imazapic on Target and Nontarget Vegetation during Revegetation

2007 ◽  
Vol 21 (4) ◽  
pp. 1071-1081 ◽  
Author(s):  
Roger L. Sheley ◽  
Michael F. Carpinelli ◽  
Kimberly J. Reever Morghan
Keyword(s):  
Prescribed Fire ◽  
Application Rate ◽  
Annual Grass ◽  
Herbicide Application ◽  
Burn Treatment ◽  
Application Rates ◽  
Nontarget Species ◽  
Annual Grasses ◽  
Winter Annual ◽  
Plot Design

Medusahead is an introduced, winter-annual grass covering millions of hectares of the semiarid West. It forms exclusive stands and has a dense thatch cover that resists the establishment of desirable species. Prescribed fire can remove medusahead litter and improve plant establishment. Medusahead control is fundamental to establishing desirable species that will, in turn, resist further invasion. Imazapic is an effective herbicide for control of medusahead, but more information is needed on its effects on desirable species. Our objectives were to test how imazapic application rate and timing affected medusahead, seeded desirable species, and other nontarget vegetation on burned and unburned rangeland in southeast Oregon. We burned existing medusahead infestations at two different sites in June 2003. Following the burn, imazapic was applied at rates of 0, 35, 70, 105, 140, 175, and 210 g ai/ha between July and October of 2003 in a randomized strip-plot design. In November 2003, monocultures of seven desirable species were drill-seeded across the imazapic treated areas. Data on cover and density of medusahead and seeded species were collected in 2004 and 2005. Cover data of nontarget species were collected in the summer of 2005. Medusahead cover was highest in control plots and lowest in plots that received the highest herbicide application rates. Medusahead cover was lower in burned plots. The effect of imazapic on nontarget vegetation was less clear. Seeded species established in the study plots, but their response to herbicide rate showed few consistent patterns; some of the seeded species showed little response to herbicide, whereas others appeared to establish best at different herbicide rates, depending on site and whether the plots were burned or unburned. Site and burn treatment also affected how imazapic rate or application month influenced cover of perennial or annual grasses or forbs.

scholarly journals Yield, germination and herbicide residue in seeds of preharvest desiccated wheat

2018 ◽  
Vol 40 (3) ◽  
pp. 304-312 ◽  
Author(s):  
Lais Tessari Perboni ◽  
Dirceu Agostinetto ◽  
Leandro Vargas ◽  
Joanei Cechin ◽  
Renan Ricardo Zandoná ◽  
...  
Keyword(s):  
Wheat Yield ◽  
Application Rate ◽  
Application Time ◽  
Herbicide Application ◽  
Herbicide Residue ◽  
Application Rates ◽  
Weight Yield ◽  
Time Periods ◽  
Dough Stage ◽  
Wheat Seeds

Abstract: The goals of this study were to evaluate herbicide application rates at different timings for preharvest desiccation of wheat (Trial 1), as well as to evaluate the effect of the timing of herbicide desiccation at preharvest and harvest timing (Trial 2) on yield, germination, and herbicide residue in wheat seed. In Trial 1, treatments consisted of two application rates of glufosinate, glyphosate, paraquat, or paraquat+diuron and a control without application; application time periods were in the milk grain to early dough stage, soft dough to hard dough stage, and hard dough stage. In Trial 2, treatments consisted of different application time periods (milk grain to early dough stage, and soft dough to hard dough stage), different herbicides (glufosinate, 2,4-D+glyphosate, and untreated control), and different harvest times (5, 10 and 15 days after herbicide application). One thousand seeds weight, yield, first and final germination count, and herbicide residue on seeds were evaluated. Preharvest desiccation with paraquat, glufosinate, and 2,4-D+glyphosate at the milk grain to early dough stage reduces wheat yield. Regardless of the herbicide and application rate, application in the milk grain to early dough stage and soft dough to hard dough stage provides greater germination of wheat seeds, except at the lower dose of paraquat. Systemic herbicides accumulate more in wheat seeds.

Dose-Responses of Weeds and Winter Wheat (Triticum aestivum) to MON 37500

1996 ◽  
Vol 10 (4) ◽  
pp. 870-875 ◽  
Author(s):  
Patrick W. Geier ◽  
Phillip W. Stahlman
Keyword(s):  
Winter Wheat ◽  
Residual Effects ◽  
Downy Brome ◽  
Annual Grass ◽  
Jointed Goatgrass ◽  
Weed Growth ◽  
Annual Grasses ◽  
Winter Annual ◽  
Dose Responses ◽  
Weed Emergence

Greenhouse studies determined the dose-responses of cheat, downy brome, Japanese brome, jointed goatgrass, and winter wheat to preplant-incorporated MON 37500 and its residual effects on kochia. Concentrations of MON 37500 up to 60 ppbw did not affect winter wheat. MON 37500 did not prevent weed emergence, but increasingly inhibited weed growth as the dose was increased up to about 20 ppbw. GR50values were 16, 16, 11, and 31 ppbw for cheat, downy brome, Japanese brome, and jointed goatgrass, respectively. Japanese brome was more susceptible than cheat or downy brome, and jointed goatgrass tolerated two to three times more MON 37500 than theBromusspecies. Plant dry weights of kochia seeded after removal of the winter annual grasses decreased with increasing initial MON 37500 concentrations up to 20 ppbw. Kochia density was influenced by which winter annual grass was grown previously.

Landscape-Scale Rehabilitation of Medusahead (Taeniatherum caput-medusae)-Dominated Sagebrush Steppe

2012 ◽  
Vol 5 (4) ◽  
pp. 436-442 ◽  
Author(s):  
Roger L. Sheley ◽  
Edward A. Vasquez ◽  
Anna-Marie Chamberlain ◽  
Brenda S. Smith
Keyword(s):  
Scaling Up ◽  
Landscape Scale ◽  
Perennial Grasses ◽  
Sagebrush Steppe ◽  
Annual Grass ◽  
Heterogeneous Landscape ◽  
Single Entry ◽  
Annual Grasses ◽  
Winter Annual ◽  
Revegetation Strategies

AbstractProducers facing infestations of invasive annual grasses regularly voice the need for practical revegetation strategies that can be applied across broad landscapes. Our objective was to determine the potential for scaling up the single-entry approach for revegetating medusahead-infested rangeland to broader, more heterogeneous landscape-scale revegetation of winter annual grass–infested rangeland. We hypothesized, when applied on a highly variable landscape scale, the combination of imazapic and seeding would provide highest abundance of perennial grasses and lowest amount of annual grasses. Treatments included a control, seeding of crested wheatgrass (‘Hycrest’) and Sandberg's bluegrass, spraying (60 g ai ha−1 imazapic), and a simultaneously applied combination of spraying and seeding. The HyCrest and Sandberg's bluegrass seeding rates were 19 and 3.4 kg ha−1, respectively. The treatments were applied to large plots (1.4 to 8 ha) and replicated five times, with each replication located in different watersheds throughout southeastern Oregon. This study shows that the single-entry approach can be scaled up to larger landscapes, but variation within establishment areas will likely be high. This procedure should reduce the costs over multientry treatment applications and make revegetating annual grass–infested rangeland across landscapes more affordable.

Synergistic Mixtures of Sethoxydim and Fluazifop on Annual Grass Weeds

1991 ◽  
Vol 5 (2) ◽  
pp. 310-316 ◽  
Author(s):  
K. Neil Harker ◽  
P. Ashley O'Sullivan
Keyword(s):  
Field Experiments ◽  
Grass Species ◽  
Research Station ◽  
Wild Oat ◽  
Annual Grass ◽  
Herbicide Application ◽  
Additive Interaction ◽  
Application Rates ◽  
Green Foxtail ◽  
Negative Environmental Impact

Greenhouse and field experiments were conducted at the Lacombe Research Station to evaluate mixtures of sethoxydim and fluazifop on green foxtail, wild oat, wheat, and barley in canola. In both environments the two herbicides interacted on the grass species in a synergistic manner. Many of the observed responses to mixtures of sethoxydim and fluazifop were 100% greater than those expected assuming an additive interaction between the herbicides. Mixtures with at least 80 g ha-1of sethoxydim and 80 g ha-1of fluazifop controlled more than 90% of green foxtail, wild oat, wheat, and barley under field conditions. These experiments indicate that the sethoxydim/fluazifop mixture is both complementary and synergistic. The mixture may allow reduced herbicide application rates and therefore reduced herbicide costs and less potential for negative environmental impact.

Influence of Herbicide Application Rate, Timing, and Interrow Cultivation on Weed Control and Corn (Zea mays) Yield in Glufosinate-Resistant and Glyphosate-Resistant Corn

1999 ◽  
Vol 13 (4) ◽  
pp. 807-813 ◽  
Author(s):  
Brent E. Tharp ◽  
James J. Kells
Keyword(s):  
Zea Mays ◽  
Weed Control ◽  
Field Trials ◽  
Application Rate ◽  
Corn Yield ◽  
Herbicide Application ◽  
Weed Species ◽  
Application Timing ◽  
Glufosinate Ammonium ◽  
Application Rates

Field trials were conducted in 1996 and 1997 to determine the influence of glufosinate and glyphosate application rates, application timings, and interrow cultivation on weed control and corn yield. Glufosinate-ammonium rates ranged from 0.18 to 0.41 kg ai/ha, while rates for the isopropylamine salt of glyphosate ranged from 0.21 to 0.84 kg ae/ha. Increasing rates of glufosinate and glyphosate often improved weed control. Control of many of the weed species was improved by delaying herbicide application timing. Weed control was most consistent from late postemergence (LPOST) applications of glufosinate at 0.41 kg ai/ha or glyphosate at 0.84 kg ae/ha. Corn yields were reduced due to incomplete weed control when the lowest rate of glufosinate was applied. Weed control from early postemergence (EPOST) glufosinate and glyphosate applications followed by cultivation was similar to weed control from LPOST glufosinate and glyphosate applications without cultivation. Interrow cultivation following glufosinate or glyphosate application did not affect corn yield.

Using Herbicides to Restore Native Species and Improve Habitat on Rangelands and Wildlands

2020 ◽  
Vol 31 (2) ◽  
pp. 57-60
Author(s):  
Shannon L. Clark
Keyword(s):  
Native Species ◽  
Fire Regime ◽  
Fire Frequency ◽  
Sagebrush Steppe ◽  
Native Plant ◽  
Intermountain West ◽  
Downy Brome ◽  
Annual Grass ◽  
Annual Grasses ◽  
Winter Annual

Invasive winter annual grasses are one of the largest threats to the arid and semiarid rangelands and wildlands in the Intermountain West of North America. The most impactful species include downy brome (Bromus tectorum), medusahead (Taeniatherum caput-medusae), ventenata (Ventenata dubia), and to a lesser extent Japanese brome (Bromus japonicus), feral rye (Secale cereale), and jointed goatgrass (Aegilops cylindrica). These winter annuals can germinate in the fall, winter or early spring, exploiting soil moisture and nutrients before native plant communities begin active growth in the spring. These characteristics impart a competitive advantage in the perennial grass dominated natural landscapes of the Intermountain West. Downy brome, a winter annual grass native to Eurasia, is the most widespread invasive species in the western US covering an estimated 22 million ha and a projected 14% annual spread rate. Invasive winter annuals negatively impact these ecosystems by depleting soil moisture and nutrients, reducing native plant productivity and diversity, altering fire frequency, and diminishing pollinator and wildlife habitat. Large amounts of litter which act as a fuel source are left after these grasses senesce early in the summer, greatly increasing the frequency and spread of wildfires in invaded areas. Historically, fire frequency in the 41 million ha sagebrush steppe occurred every 60 to 110 years, but this interval has been shortened to less than every five years since the introduction of invasive annual grasses. Annual grasses quickly (re)invade after these fires while sagebrush (Artemisia spp.), the dominant vegetation type in the sagebrush steppe, can take decades to recover. Therefore, the altered fire regime has resulted in a substantial loss of sagebrush and converted millions of hectares into monocultures of winter annual grass. This altered fire regime also negatively impacted the abundance of small mammals, birds, larger browsing mammals, and pollinating insects in the sagebrush steppe. Managing the weed seedbank is the key to long-term control of invasive winter annual grasses on rangelands and wildlands. Past herbicides have provided adequate short-term control but have often failed due to annual grasses reinvading from the soil seedbank. Indaziflam is a new tool for land managers to achieve multi-year control of the annual grass seedbank while promoting restoration of native species. As wildlife and pollinator habitat continue to be degraded and fragmented through development and agricultural production, indaziflam is a viable option for restoring the rangelands and wildlands impacted by winter annual grasses in the Intermountain West that serve as critical habitat areas.

Response of Sweetpotato Cultivars to Linuron Rate and Application Time

2018 ◽  
Vol 32 (6) ◽  
pp. 665-670 ◽  
Author(s):  
Shawn C. Beam ◽  
Katherine M. Jennings ◽  
Sushila Chaudhari ◽  
David W. Monks ◽  
Jonathan R. Schultheis ◽  
...  
Keyword(s):  
North Carolina ◽  
Field Studies ◽  
Application Rate ◽  
Application Time ◽  
Herbicide Application ◽  
Application Rates

AbstractField studies were conducted in 2015 and 2016 in North Carolina to determine the response of ‘Covington’ and ‘Murasaki-29’ sweetpotato cultivars to four rates of linuron (420, 560, 840, and 1,120 g ai ha–1) alone or withS-metolachlor (803 g ai ha–1) applied 7 or 14 d after transplanting (DAP). Injury (chlorosis/necrosis and stunting) to both cultivars was greater when linuron was applied withS-metolachlor as compared to linuron applied alone. Herbicide application at 14 DAP caused greater injury (chlorosis/necrosis and stunting) to both cultivars than when applied at 7 DAP. At 4 wk after treatment (WAT), stunting of Covington and Murasaki-29 (hereafter Murasaki) from linuron at 420 to 1,120 g ha–1increased from 27% to 50% and 25% to 53%, respectively. At 7 or 8 WAT, crop stunting of 8% or less and 0% was observed in Covington and Murasaki, respectively, regardless of application rate and timing. Murasaki root yields were similar in the linuron alone or withS-metolachlor treatments, and were lower than the nontreated check. In 2016, no. 1 and marketable sweetpotato yields of Covington were similar for the nontreated check, linuron alone, or linuron plusS-metolachlor treatments, but not in 2015. Decreases in no. 1 and marketable root yields were observed when herbicides were applied 14 DAP compared to 7 DAP for Covington in 2015 and for Murasaki in both years. No. 1 and marketable yields of Covington were similar for 420 to 1,120 g ha–1linuron and nontreated check except marketable root yields in 2015. No. 1 and marketable sweetpotato yields of Murasaki decreased as application rates increased.

scholarly journals Summer Annual and Winter Annual Weed Control in Field Soil and Soilless Media with Gallery (lsoxaben)

1990 ◽  
Vol 8 (3) ◽  
pp. 124-127
Author(s):  
Joseph C. Neal ◽  
Andrew F. Senesac
Keyword(s):  
Weed Control ◽  
Field Soil ◽  
Annual Grass ◽  
Annual Bluegrass ◽  
Soilless Media ◽  
Application Rates ◽  
Potting Medium ◽  
Excellent Control ◽  
Winter Annual

Abstract Field and container experiments were conducted to evaluate Gallery (isoxaben) efficacy on several common nursery and landscape weeds. Gallery was applied at rates from 0.14 to 1.1 kg ai/ha (0.125 and 1 lb ai/A). Annual grass control with Gallery generally was poor at application rates below 0.84 kg/ha (0.75 lb/A). Higher rates were needed for consistent foxtail and annual bluegrass control. Gallery controlled most broadleaf weeds at ≤0.56 kg/ha (0.5 lb/A) in field soil and a soilless potting medium. The exception was velvetleaf, which was not controlled with 1.1 kg/ha (1 lb/A). Combining Gallery with Surflan (Snapshot) at 1.1 + 3.4 kg/ha (1 + 3 lb/A) provided excellent control of all weeds tested. Equivalent weed control was obtained with a tank mix of Gallery plus Surflan at 0.28 + 3.4 kg/ha (0.25 + 3 lb/A) in 1989, suggesting that when used in combination with Surflan the rate of Gallery may be reduced relative to the comparable Snapshot rate, without sacrificing weed control.

Control of annual grasses by spraytopping and the effect on triticale grain yield

1993 ◽  
Vol 44 (8) ◽  
pp. 1959 ◽  
Author(s):  
PM Dowling ◽  
HI Nicol
Keyword(s):  
Grain Yield ◽  
Seed Set ◽  
Application Rate ◽  
Wetting Agent ◽  
Annual Grass ◽  
Annual Grasses ◽  
Total Seed ◽  
Main Component ◽  
Grass Sward ◽  
Grass Weed

IA range of pre-season management treatments was imposed on a mixed annual grass sward in October 1987, prior to planting triticale into a cultivated and a direct-drilled seedbed in June 1988. The management treatments included three rates of glyphosate: Roundup� (110, 180, 360 g a.i./ha); two rates of paraquat: Gramoxone� (100, 200 g a.i. ha); and one rate of fluazifop-butyl: Fusilade� (53 g a.i./ha � Pulse� wetting agent). All treatments decreased potential grass regeneration, with V. bromozdes being the least affected. Improved control was achieved by increasing application rate, and by adding a wetting agent to fluazifop. Actual grass seedlings emerging within the crop followed a similar pattern to potential grass regeneration. Grass emergence, particularly of V. bromoides and L. rigidum, was always greater on the direct-drilled seedbed. Grain yield was greater on the prepared seedbed. On both seedbeds, yield was inversely related to grass DM 97 days after sowing (DAS) and grass weed seedling numbers 50 DAS. The effectiveness of the herbicides appeared to be related to maturity dates of the target species. The high potential seed-set of the annual grasses present (> 500 000/m2), of which V. bromozdes was the main component, highlights the difficulty of controlling such species. It is suggested that the large apparent decline from total seed-set to potential seedling numbers (14000/m2) resulted from the high stocking pressure by sheep over summer. For a number of annual grasses, a more rapid method for determining seed number based on seed weight and seedhead number is proposed, providing a more informed basis for decision making. We conclude that spraytopping to maximize yield of later sown direct-drilled crops (e.g. triticale) is essential, despite the difficulty in optimizing timing of spraytopping in mixed pasture swards.

Environmental Benefits of Precision Agriculture Adoption

2020 ◽  
pp. 637-656 ◽  
Author(s):  
Marco Medici ◽  
Søren Marcus Pedersen ◽  
Giacomo Carli ◽  
Maria Rita Tagliaventi
Keyword(s):  
Environmental Impacts ◽  
Precision Agriculture ◽  
New Technologies ◽  
Environmental Benefits ◽  
Herbicide Application ◽  
Pesticide Application ◽  
Policy Makers ◽  
Application Rates ◽  
Biodiversity Policy ◽  
Lime Application

The purpose of this study is to analyse the environmental benefits of precision agriculture technology adoption obtained from the mitigation of negative environmental impacts of agricultural inputs in modern farming. Our literature review of the environmental benefits related to the adoption of precision agriculture solutions is aimed at raising farmers' and other stakeholders' awareness of the actual environmental impacts from this set of new technologies. Existing studies were categorised according to the environmental impacts of different agricultural activities: nitrogen application, lime application, pesticide application, manure application and herbicide application. Our findings highlighted the effects of the reduction of input application rates and the consequent impacts on climate, soil, water and biodiversity. Policy makers can benefit from the outcomes of this study developing an understanding of the environmental impact of precision agriculture in order to promote and support initiatives aimed at fostering sustainable agriculture.

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