scholarly journals Seed shattering phenology at soybean harvest of economically important weeds in multiple regions of the United States. Part 1: broadleaf species

Weed Science ◽  
2020 ◽  
pp. 1-29
Author(s):  
Lauren M. Schwartz-Lazaro ◽  
Lovreet S. Shergill ◽  
Jeffrey A. Evans ◽  
Muthukumar V. Bagavathiannan ◽  
Shawn C. Beam ◽  
...  
Keyword(s):  
The United States ◽  
Ambrosia Artemisiifolia ◽  
Retention Rates ◽  
Weed Species ◽  
Physiological Maturity ◽  
Seed Retention ◽  
Northern Latitudes ◽  
Multiple Regions ◽  
Broadleaf Species ◽  
Crop Maturity

Abstract Potential effectiveness of harvest weed seed control (HWSC) systems depends upon seed shatter of the target weed species at crop maturity, enabling its collection and processing at crop harvest. However, seed retention likely is influenced by agroecological and environmental factors. In 2016 and 2017, we assessed seed shatter phenology in thirteen economically important broadleaf weed species in soybean [Glycine max (L.) Merr.] from crop physiological maturity to four weeks after physiological maturity at multiple sites spread across fourteen states in the southern, northern, and mid-Atlantic U.S. Greater proportions of seeds were retained by weeds in southern latitudes and shatter rate increased at northern latitudes. Amaranthus species seed shatter was low (0 to 2%), whereas shatter varied widely in common ragweed (Ambrosia artemisiifolia L.) (2 to 90%) over the weeks following soybean physiological maturity. Overall, the broadleaf species studied shattered less than ten percent of their seeds by soybean harvest. Our results suggest that some of the broadleaf species with greater seed retention rates in the weeks following soybean physiological maturity may be good candidates for HWSC.

scholarly journals Seed shattering phenology at soybean harvest of economically important weeds in multiple regions of the United States. Part 2: grass species

Weed Science ◽  
2020 ◽  
pp. 1-19
Author(s):  
Lauren M. Schwartz-Lazaro ◽  
Lovreet S. Shergill ◽  
Jeffery A. Evans ◽  
Muthukumar V. Bagavathiannan ◽  
Shawn C. Beam ◽  
...  
Keyword(s):  
The United States ◽  
Grass Species ◽  
Annual Grass ◽  
Weed Seed ◽  
Weed Species ◽  
Seed Shattering ◽  
Physiological Maturity ◽  
Rate Of Progression ◽  
Multiple Regions ◽  
Grass Weed

Abstract Seed shatter is an important weediness trait on which the efficacy of harvest weed seed control (HWSC) depends. The level of seed shatter in a species is likely influenced by agroecological and environmental factors. In 2016 and 2017, we assessed seed shatter of eight economically important grass weed species in soybean [Glycine max (L.) Merr.] from crop physiological maturity to four weeks after maturity at multiple sites spread across eleven states in the southern, northern, and mid-Atlantic U.S. From soybean maturity to four weeks after maturity, cumulative percent seed shatter was lowest in the southern U.S. regions and increased as the states moved further north. At soybean maturity, the percent of seed shatter ranged from 1 to 70%. That range had shifted to 5 to 100% (mean: 42%) by 25 days after soybean maturity. There were considerable differences in seed shatter onset and rate of progression between sites and years in some species that could impact their susceptibility to HWSC. Our results suggest that many summer annual grass species are likely not ideal candidates for HWSC, although HWSC could substantially reduce their seed output at during certain years.

Seed Longevity of 41 Weed Species Buried 17 Years in Eastern and Western Nebraska

Weed Science ◽  
1996 ◽  
Vol 44 (1) ◽  
pp. 74-86 ◽  
Author(s):  
Orvin C. Burnside ◽  
Robert G. Wilson ◽  
Sanford Weisberg ◽  
Kenneth G. Hubbard
Keyword(s):  
Great Plains ◽  
Weed Management ◽  
The United States ◽  
Decay Rates ◽  
Management Systems ◽  
Annual Grass ◽  
Weed Species ◽  
Seed Germinability ◽  
Soil Temperatures ◽  
Broadleaf Species

Seed of 41 economically important weed species of the Great Plains region of the United States were buried 20 cm deep in soil in eastern and western Nebraska in 1976. The 41 species consisted of 11 annual grass, 14 annual broadleaf, 4 biennial broadleaf, and 12 perennial broadleaf species. Weed seeds were exhumed annually for germination tests the first 9 yr, then after 12 and 17 yr. Germination percentages at the two burial locations averaged over 0, 1 to 4, 5 to 8, and 9 to 17 yr of burial were 57, 28, 9, and 4% for annual grass; 47, 26, 16, and 11 % for annual broadleaf; 52, 49, 44, and 30 % for biennial broadleaf; 36, 18, 13, and 8% for perennial broadleaf; and 47, 26, 16, and 10% for all 41 weed species, respectively. Biennial broadleaf weeds showed the greatest seed germination over years. Annual grass weeds showed less seed germinability over 17 yr of burial than annual broadleaf weeds and perennial broadleaf weed species were intermediate. Weed seed germinability in soil was greater in the reduced rainfall and more moderate soil temperatures of western Nebraska than in the greater rainfall and more fluctuating soil temperatures of eastern Nebraska. The greatest seed survival among the 41 weed species was shown by common mullein, which had 95% germination after 17 yr of burial in western Nebraska. Decay rates of individual weed species in soil will be of most value to weed scientists, agriculturalists, and modelers evaluating past or designing future weed management systems.

scholarly journals Seed shattering phenology at soybean harvest of economically important weeds in multiple regions of the United States. Part 3: Drivers of seed shatter

Weed Science ◽  
2021 ◽  
pp. 1-26
Author(s):  
Lauren M. Schwartz-Lazaro ◽  
Lovreet S. Shergill ◽  
Jeffrey A. Evans ◽  
Muthukumar V. Bagavathiannan ◽  
Shawn C. Beam ◽  
...  
Keyword(s):  
Management Practices ◽  
Plant Biomass ◽  
Weather Conditions ◽  
Field Studies ◽  
The United States ◽  
Weed Seed ◽  
Weed Species ◽  
Seed Shattering ◽  
Early Season ◽  
Multiple Regions

Seed retention, and ultimately seed shatter, are extremely important for the efficacy of harvest weed seed control (HWSC) and likely influenced by various agro-ecological and environmental factors. Field studies investigated seed shattering phenology of 22 weed species across three soybean [Glycine max (L.) Merr.] producing regions in the US. We further evaluated the potential drivers of seed shatter in terms of weather conditions, growing degree days, and plant biomass. Based on the results, weather conditions had no consistent impact on weed seed shatter. However, there was a positive correlation between individual weed plant biomass and delayed weed-seed shattering rates during harvest. This work demonstrates that HWSC can potentially reduce weed seedbank inputs of plants that have escaped early season management practices and retained seed through harvest. However, smaller individuals of plants within the same population that shatter seed before harvest pose a risk of escaping early season management and HWSC.

Promoting divergent leadership philosophies to improve student success outcomes for black and brown students in higher education

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Nicholas Petty ◽  
Dakota King-White ◽  
Tachelle Banks
Keyword(s):  
Higher Education ◽  
United States ◽  
Student Success ◽  
Baccalaureate Degree ◽  
The United States ◽  
Retention Rates ◽  
Completion Rates ◽  
Marginalized Groups ◽  
Support Students

Abstract Throughout the United States there are millions of Black and Brown students starting the process of attending college. However, research indicates that students from traditionally marginalized groups are less likely than their counterparts to complete the process and graduate college (Shapiro et al., 2017). While retention rates for students from traditionally marginalized backgrounds continue to decline, universities are beginning to pay attention to the needs of this population in search of ways of better supporting them. The examination of these factors may also inform programmatic adjustments, leadership philosophies, and future practices to help retain students and lead to eventual completion of a baccalaureate degree. In this article, the authors review the literature to explore factors that can affect Black and Brown students’ completion rates in higher education. By reviewing the literature and the factors impacting Black and Brown students, the authors share with readers initiatives at one university that are being used to support students from a strengths-based approach.

Herbicide Effects on Weed Control and Shoot Growth of Young Apple (Malus sylvestris) and Peach (Prunus persica) Trees

1994 ◽  
Vol 8 (4) ◽  
pp. 840-848 ◽  
Author(s):  
Chester L. Foy ◽  
Susan B. Harrison ◽  
Harold L. Witt
Keyword(s):  
Shoot Growth ◽  
Field Experiments ◽  
Prunus Persica ◽  
Weed Species ◽  
Apple Trees ◽  
Herbicide Treatments ◽  
One Year ◽  
Broadleaf Species ◽  
Old Trees ◽  
Peach Trees

Field experiments were conducted at two locations in Virginia to evaluate the following herbicides: alachlor, diphenamid, diuron, metolachlor, napropamide, norflurazon, oryzalin, oxyfluorfen, paraquat, pendimethalin, and simazine. One experiment involved newly-transplanted apple trees; the others, three in apple and one in peach trees, involved one-year-old trees. Treatments were applied in the spring (mid-April to early-May). Control of annual weed species was excellent with several treatments. A broader spectrum of weeds was controlled in several instances when the preemergence herbicides were used in combinations. Perennial species, particularly broadleaf species and johnsongrass, were released when annual species were suppressed by the herbicides. A rye cover crop in nontreated plots suppressed the growth of weeds. New shoot growth of newly-transplanted apple trees was increased with 3 of 20 herbicide treatments and scion circumference was increased with 11 of 20 herbicide treatments compared to the nontreated control. Growth of one-year-old apple trees was not affected. Scion circumference of one-year-old peach trees was increased with 25 of 33 herbicide treatments.

scholarly journals Volunteers’ Felt Respect and Its Associations With Volunteering Retention, Daily Affect, Well-being, and Mortality

2018 ◽  
Vol 75 (8) ◽  
pp. 1625-1636 ◽  
Author(s):  
Dwight C K Tse
Keyword(s):  
United States ◽  
Negative Affect ◽  
Positive Affect ◽  
Well Being ◽  
The United States ◽  
National Sample ◽  
Retention Rates ◽  
Mortality Data ◽  
Volunteer Work ◽  
Daily Affect

Abstract Objectives Volunteering is associated with improved physical and psychological well-being; volunteers feeling more respect for their work may have better well-being than their counterparts. Methods This study investigated the effects of felt respect for volunteer work on volunteering retention, daily affect, well-being (subjective, psychological, and social), and mortality. The study analyzed survey and mortality data from a national sample of 2,677 volunteers from the Midlife in the United States Study over a 20-year span. Daily affect data were obtained from a subsample of 1,032 volunteers. Results Compared to volunteers feeling less respect from others, those feeling more respect (a) were more likely to continue volunteering 10 and 20 years later, (b) had higher levels of daily positive affect and lower levels of daily negative affect, and (c) had higher levels of well-being over a 20-year period. The effect of felt respect on mortality was not statistically significant. Discussion Greater level of felt respect for volunteer work is positively related to volunteers’ retention rates, daily affective experience, and well-being.

scholarly journals Efficiency of glyphosate and ammonium glufosinate against common ragweed (Ambrosia artemisiifolia L.) in vineyards

2019 ◽  
pp. 45-50
Author(s):  
A. S. Golubev ◽  
I. P. Borushko ◽  
V. I. Dolzhenko
Keyword(s):  
Quantitative Method ◽  
Application Rate ◽  
Ambrosia Artemisiifolia ◽  
Cabernet Sauvignon ◽  
Weed Species ◽  
Common Ragweed ◽  
Glufosinate Ammonium ◽  
Ammonium Glufosinate ◽  
Effi Ciency ◽  
Krasnodar Region

The use of glyphosate (720-2880 g/h a.i.) and ammonium glufosinate herbicides (375-1500 g/h a.i.) to control of common ragweed (Ambrosia artemisiifolia L.) has been studied in trials (2013-2018) in the vineyards of Rkatsiteli, Liang and Cabernet Sauvignon in Abinsk district of Krasnodar region. Accounting of weeds was done by a quantitative method with counting the number of each weed species in each plot. Counts were performed before the treatment and in 15, 30 and 45 days after spraying. The effi cacy of herbicide was determined in relation to the untreated control and expressed as a percentage. The main evaluation criterion was the eff ectiveness of 100 % in one of the accounts or the average (for all counts) effi ciency of more than 90 %. The results showed that in 95 % of trials spraying of 1440 g/h of glyphosate 1440 g/h of glyphosate (a.i.) and higher ensured processing effi ciency exceeding 90 %. Herbicides such as Roundup, containing 360 g/l of isopropylamine salt, can be recommended for use to control of common ragweed in the application rate 4.0 l/ha. Destruction of all common ragweed observed when using not less than 600 g/h glufosinate ammonium. Thus, Herbicides such as Basta, containing 150 g/l of ammonium glufosinate, to control of common ragweed should be applied by fractional application vegetative weeds (2.5 l/h + 1.5 l/h).

scholarly journals A promising method to control ragweed Ambrosia artemisiifolia L. in urban cenoses

2021 ◽  
Vol 285 ◽  
pp. 02018
Author(s):  
Leonid Esipenko ◽  
Almaskhan Ketsba
Keyword(s):  
Invasive Plants ◽  
Agricultural Production ◽  
Allergic Diseases ◽  
Ambrosia Artemisiifolia ◽  
Economic Consequences ◽  
Economic Damage ◽  
Weed Species ◽  
The World ◽  
Positive Results ◽  
Modern Technologies

Invasions of adventive weed species are one of the leading factors in the transformation of agrobiocenoses and urban cenoses. Naturalization of new species leads to serious ecological, social and economic consequences. One of the dangerous invasive plants is ragweed (Ambrosia artemisiifolia L.), which is widespread in many countries of the world, including Russia. This weed plant causes significant economic damage and harmful impact on human health, since its pollen is a strong allergen. Modern technologies of agricultural production do not always give positive results in the fight against this plant. Therefore, it is necessary to develop new ecologically low-hazard methods to control it, aimed at reducing the productivity of pollen and seeds in order to reduce allergic diseases among people and limit the expansion of its range.

scholarly journals Implementing a Low-threshold Audio-only Telehealth Model for Medication-assisted Treatment of Opioid Use Disorder at a Community-based Non-profit Organization in Washington, D.C.

2021 ◽  
Author(s):  
Ellis Jaewon Yeo ◽  
Hannah Kralles ◽  
David Sternberg ◽  
Dana McCullough ◽  
Ajetha Nadanasabesan ◽  
...  
Keyword(s):  
Patient Characteristics ◽  
The United States ◽  
Opioid Use Disorder ◽  
Retention Rates ◽  
People Who Use Drugs ◽  
Opioid Use ◽  
Treatment Access ◽  
Community Based ◽  
Medication Assisted Treatment ◽  
Low Threshold

Abstract BackgroundThe COVID-19 pandemic has had especially devastating effects on people who use drugs. Due to pandemic protocols in the United States, medication-assisted treatment (MAT) regulations became more flexible, permitting our community-based nonprofit organization to transition its low-threshold MAT clinic to an audio-only telehealth model of care in 2020. Case PresentationThis case study describes our transition from a low-threshold community-based in-person MAT clinic to an audio-only telehealth model. We extracted data from electronic health records to describe patient characteristics and to calculate treatment retention rates. We measure the success of our intervention relative to published retention rates, both overall as well as for in-person and telehealth care. ConclusionsLow-threshold medication-assisted treatment in the care of people with opioid use disorder is essential to increasing treatment access and continuity. We found that an audio-only telehealth model was viable. Although we had decreased retention rates following the transition to an audio-only telehealth model, our rates remained excellent compared to published values for in-person MAT care. We call for advocacy and regulations to support continued use of telehealth services throughout and beyond the COVID-19 pandemic.

scholarly journals The United States Glaciological Researches during the International Geophysical Year

1962 ◽  
Vol 4 (31) ◽  
pp. 5-24 ◽  
Author(s):  
A. P. Crary ◽  
W. O. Field ◽  
M. F. Meier
Keyword(s):  
United States ◽  
Ice Cover ◽  
The United States ◽  
International Geophysical Year ◽  
Northern Latitudes ◽  
International Geophysical ◽  
The U.S

AbstractThe U.S. IGY program in glaciology is reviewed in two parts: Antarctica and northern latitudes. The objectives of the program are outlined and the results of each investigation are briefly summarized. A separate discussion of observations related to changes in the Earth’s ice cover is included.

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