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George O. Kegode - One of the best experts on this subject based on the ideXlab platform.
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Biennial wormwood (Artemisia biennis) competition with soybean (Glycine max)
Article scientifique, 2005Co-Authors: Eric A. Nelson, George O. KegodeAbstract:Biennial wormwood has become a serious weed of several crops in the northern Great Plains of the United States and Prairie Provinces of Canada. Greenhouse replacement series experiments were conducted to investigate the effects of watering regime (stressed and non-stressed) and nitrogen rate (50, 100, 150, and 200 mg kg-1 of soil) on competition between soybean and biennial wormwood. Soybean height was reduced after 9 weeks of competition with biennial wormwood compared with soybean grown in monoculture, whereas biennial wormwood plants were taller when grown with soybean than in monoculture. The change in plant height indicated that biennial wormwood height was increased due to interspecific competition, whereas soybean height was reduced. When moisture was limited, the relative yield of biennial wormwood was greater than that of soybean, indicating that biennial wormwood was more aggressive than soybean. Soybean growth was unaffected by an increase in nitrogen rate, whereas biennial wormwood fresh weight was 30% greater when the nitrogen rate was increased from 50 to 200 mg kg-1. Biennial wormwood aggressivity tended to increase as the nitrogen rate was increased from 50 to 200 mg kg-1. Overall results suggest that the negative impact of biennial wormwood competition with soybeans under field conditions may increase when soil moisture is limited and nitrogen fertility is increased.
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Biennial Wormwood (Artemisia biennis) Early-Season Control with Herbicides
Weed Technology, 2004Co-Authors: Bradley E. Fronning, George O. KegodeAbstract:Biennial wormwood has become a problem for soybean producers in the northern Great Plains of the United States. Research was conducted to evaluate control of biennial wormwood with preemergence (PRE) herbicides alone or followed by postemergence (POST) herbicides in 2000 and 2001 at Fargo, Leonard, and Wyndmere, ND. Favorable soil moisture conditions at Leonard resulted in continual emergence and greater densities of biennial wormwood, whereas the soil at Fargo and Wyndmere was dry and few biennial wormwood seedlings emerged at these locations. Biennial wormwood control with PRE herbicides was greater than 89% at Fargo and Wyndmere but was 80% or lower at Leonard. PRE biennial wormwood control was higher with flumetsulam than with sulfentrazone. When POST treatments were applied after PRE herbicides, biennial wormwood control 4 wk after treatment was 92% or better at Fargo and Wyndmere but was 76% or less at Leonard. The combination of PRE and POST herbicide treatments did not improve control greatly at F...
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Genetic diversity of biennial wormwood.
Weed Science, 2004Co-Authors: Lemma W. Mengistu, Michael J. Christoffers, George O. KegodeAbstract:Abstract Biennial wormwood is native to North America and has become an important weed problem in soybean and dry bean fields of North Dakota, South Dakota, and Minnesota in the United States and in the prairie provinces of Canada. Intersimple sequence repeat (ISSR) markers were used to study the genetic diversity among six biennial wormwood and one annual wormwood populations. Deoxyribonucleic acid (DNA) sequences from internal transcribed spacer (ITS1 and ITS2) regions of ribosomal DNA and morphological diversity among the biennial and annual wormwood populations were also studied. High levels of genetic diversity were evident with Nei's gene diversity statistic (h) = 0.40 for biennial wormwood and h = 0.36 for annual wormwood. Total diversity of six biennial wormwood populations was HT = 0.40, and 22% of this diversity was among populations (GST = 0.22). Estimated gene flow among biennial wormwood populations was low (Nm = 0.9), and high levels of differentiation may be due in part to low levels of gen...
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Biennial wormwood (Artemisia biennis) postemergence control in soybean.
Weed Technology, 2004Co-Authors: Bradley E. Fronning, George O. KegodeAbstract:Biennial wormwood has become an important weed for soybean producers in the northern Great Plains states of the United States. Research was conducted at Fargo, Leonard, and Wyndmere, ND, in 2000 and 2001 to evaluate postemergence control of biennial wormwood in soybean. Biennial wormwood densities at Fargo, Leonard, and Wyndmere were 290, 290, and 130 plants/m2 in 2000 and 22, 670, and 88 plants/m2 in 2001, respectively. Across years, biennial wormwood control with postemergence herbicides 4 wk after treatment was 81 to 97% at Fargo, 5 to 89% at Leonard, and 2 to 95% at Wyndmere. Biennial wormwood control was greater at Fargo than at the other locations probably because of smaller seedling size at the time of treatment. Bentazon split applied at the rate of 560 g ai/ha followed by 560 g/ha approximately 12 d after the first treatment generally provided the least amount of injury to soybean, the greatest control of biennial wormwood, and the fewest escaped plants. Lactofen at 220 g ai/ha or split applied a...
Steve Sutherland - One of the best experts on this subject based on the ideXlab platform.
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What makes a weed a weed: life history traits of native and exotic plants in the USA
Oecologia, 2004Co-Authors: Steve SutherlandAbstract:I compared ten life history traits (vegetative reproduction, breeding system, compatibility, pollination system, shade tolerance, habitat, life span, life form, morphology, and toxicity) from two existing databases for the 19,960 plant species that occur in the USA. I used two-way tests of independence to determine if there were significant life history traits that distinguish weeds from non-weeds, exotic weeds from native weeds, and invasive exotic weeds from non-invasive exotic weeds. Life span was the most significant life history trait for weeds in general; weeds were more likely to be annuals and Biennials and less likely to perennials than non-weeds. In addition, vegetative reproduction, breeding system, compatibility, shade tolerance, and life form were related to life span. Annual and biennial weeds (whether native, exotic, or exotic invasives) were more likely to be wetland adapted, armed, and toxic than annual or biennial non-weeds. Perennial weeds (whether native, exotic, or exotic invasives) were less likely to be forbs or subshrubs, and more likely to be wetland adapted, toxic, shade intolerant, grasses, vines and trees than perennial non-weeds. Exotic annual and perennial weeds were less likely to be wetland species than native weeds, but more likely to be wetland species than non-weeds. Invasive exotic weeds, in contrast, were less likely to be forbs and more likely to be perennial, monoecious, self-incompatible, and trees and than non-invasive exotics.
Monica Sassatelli - One of the best experts on this subject based on the ideXlab platform.
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symbolic production in the art biennial making worlds
Theory Culture & Society, 2017Co-Authors: Monica SassatelliAbstract:Biennials – periodic, independent and international exhibitions surveying trends in visual art – have with startling speed become key nodes in linking production, distribution and consumption of contemporary art. Cultural production and consumption have been typically separated in research, neglecting phenomena, like Biennials, sitting in between. Biennials have become, however, key sites of both the production of art’s discourse and where that discourse translates into practices of display and contexts of appreciation. They are, this article argues, key sites of art’s symbolic production. Symbolic production is what makes a work, an artist, or even a genre visible and relevant, providing its sense in a system of classifications and, in an exhibition like a biennial, literally giving it a place in the scene. This article proposes a cultural analysis of Biennials, focusing on the Venice Biennale, founded in 1895 and the first of the genre, through which we can trace Biennials’ rise and transformations.
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Visual Arts Festivals and Globalisation, The rise of Biennials
Focus on World Festivals, 2016Co-Authors: Monica SassatelliAbstract:Biennials or biennales are periodic, independent and international art exhibitions surveying trends in contemporary art; since the 1990s they have proliferated across the globe. Biennials are much more than curated displays, they constitute ‘festival-exhibitions’ working as “a public model and a shifting backdrop against which the meanings of contemporary art are constructed, maintained and sometimes irrevocably altered” (Ferguson et al., 2005: 48). Whilst most contemporary post-traditional festivals (Giorgi and Sassatelli, 2011) have ancient roots, it is only in recent years that they have become an almost ubiquitous fixture of cultural calendars in cities around the world. This current proliferation is even more striking for art Biennials. They arguably originate from the Venice Biennale, held for the first time in 1895, but have long exceeded their European, Western origin to establish a global format. Up to the 1980s they were only reproduced in a handful of examples; today Biennials and derivates (triennials and others) have become key institutional nodes linking production, consumption and distribution of contemporary art. With now over 150 Biennials around the world, we are increasingly likely to encounter contemporary art through their mediation, directly as visitors or more indirectly via the nebula of critical discourse and more generally the media coverage they generate. The phenomenon attracting attention has become not just the Biennials but more specifically the biennalisation of the art world. The term biennalisation is used within the art world itself as shorthand to refer to the proliferation and standardisation of biennial exhibitions under a common (if rather loose) format. Sociologically, biennalisation can thematise the shifting set of cultural classifications, practices and values that differentiate the contemporary art world, affecting both its content (now sometimes referred to as biennial art) and the type of rationale and experience it crystallises. As phenomena that increasingly represent themself “on a global scale” (Vogel 2010), Biennials offer a unique vantage point to access what is often termed ‘global culture’. However, they remain rarely empirically studied in clearly defined contexts, especially beyond affirmation or negations of their measurable impact (Buchholz and Wuggenig, 2005). Reprising within the art world unsolved dilemmas in the analysis of cultural globalisation, alleged optimists see in Biennials the “embracing of a democratic redistribution of cultural power” (De Duve 2009: 45); whilst pessimists point rather to the “recognition of a new form of cultural hegemony and re-colonization” (2009: 45). This chapter traces the rise of the biennial, across time and space, providing contextualisation and interpretation for what are now often hyperbolic accounts of “hundreds of Biennials” (Seijdel 2009: 4) across the globe.
Joseph Riov - One of the best experts on this subject based on the ideXlab platform.
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fruit thinning using naa shows potential for reducing biennial bearing of barnea and picual oil olive trees
Crop & Pasture Science, 2009Co-Authors: Amnon Bustan, Shimon Lavee, Avishai Avni, Joseph RiovAbstract:Biennial bearing is a major horticultural and economic drawback of olive (Olea europaea L.) cultivation, which particularly affects the olive oil industry under intensive production systems. The number of fruits per tree in an on-year is a primary determinant of the biennial cycle. While fruit thinning using NAA shortly after full bloom is commonly practiced to increase fruit size in table olives, the extent of its influence on biennial bearing is unknown. In the present study, the ability of that common naphthaleneacetic acid (NAA) treatment (100 mg/L, 10 days after full bloom) to alleviate biennial bearing in two oil olive cultivars, Picual and Barnea, was poor, although significant influence on the number of fruit was evident solely in Barnea. Picual seemed less susceptible than Barnea to biennial bearing. Consequently, the effect of a broad range of NAA concentrations (0–320 mg/L, 10 days after full bloom) on various yield parameters was investigated during a biennial cycle of Barnea trees. There was a gradual proportional decline in the on-year number of fruits from ~50 000 to 10 000/tree in response to increasing NAA concentrations. The number of return fruits in the off-year was reciprocal to the on-year fruit load, but remained relatively small, below 15 000/tree. The dynamic relationship between fruit load and fruit size in both on- and off-years was a significant compensation factor in fruit and oil yields. In both cultivars, an on-year fruit load smaller than 20 000/tree is likely to provide consistent yearly oil yields ranging from 10 to 12 kg/tree. The results demonstrate the possibility of using NAA post-bloom spraying to balance biennial bearing in oil olives.
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Fruit thinning using NAA shows potential for reducing biennial bearing of ‘Barnea’ and ‘Picual’ oil olive trees
Crop & Pasture Science, 2009Co-Authors: Amnon Bustan, Shimon Lavee, Avishai Avni, Joseph RiovAbstract:Biennial bearing is a major horticultural and economic drawback of olive (Olea europaea L.) cultivation, which particularly affects the olive oil industry under intensive production systems. The number of fruits per tree in an on-year is a primary determinant of the biennial cycle. While fruit thinning using NAA shortly after full bloom is commonly practiced to increase fruit size in table olives, the extent of its influence on biennial bearing is unknown. In the present study, the ability of that common naphthaleneacetic acid (NAA) treatment (100 mg/L, 10 days after full bloom) to alleviate biennial bearing in two oil olive cultivars, Picual and Barnea, was poor, although significant influence on the number of fruit was evident solely in Barnea. Picual seemed less susceptible than Barnea to biennial bearing. Consequently, the effect of a broad range of NAA concentrations (0–320 mg/L, 10 days after full bloom) on various yield parameters was investigated during a biennial cycle of Barnea trees. There was a gradual proportional decline in the on-year number of fruits from ~50 000 to 10 000/tree in response to increasing NAA concentrations. The number of return fruits in the off-year was reciprocal to the on-year fruit load, but remained relatively small, below 15 000/tree. The dynamic relationship between fruit load and fruit size in both on- and off-years was a significant compensation factor in fruit and oil yields. In both cultivars, an on-year fruit load smaller than 20 000/tree is likely to provide consistent yearly oil yields ranging from 10 to 12 kg/tree. The results demonstrate the possibility of using NAA post-bloom spraying to balance biennial bearing in oil olives.
Bradley E. Fronning - One of the best experts on this subject based on the ideXlab platform.
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Biennial Wormwood (Artemisia biennis) Early-Season Control with Herbicides
Weed Technology, 2004Co-Authors: Bradley E. Fronning, George O. KegodeAbstract:Biennial wormwood has become a problem for soybean producers in the northern Great Plains of the United States. Research was conducted to evaluate control of biennial wormwood with preemergence (PRE) herbicides alone or followed by postemergence (POST) herbicides in 2000 and 2001 at Fargo, Leonard, and Wyndmere, ND. Favorable soil moisture conditions at Leonard resulted in continual emergence and greater densities of biennial wormwood, whereas the soil at Fargo and Wyndmere was dry and few biennial wormwood seedlings emerged at these locations. Biennial wormwood control with PRE herbicides was greater than 89% at Fargo and Wyndmere but was 80% or lower at Leonard. PRE biennial wormwood control was higher with flumetsulam than with sulfentrazone. When POST treatments were applied after PRE herbicides, biennial wormwood control 4 wk after treatment was 92% or better at Fargo and Wyndmere but was 76% or less at Leonard. The combination of PRE and POST herbicide treatments did not improve control greatly at F...
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Biennial wormwood (Artemisia biennis) postemergence control in soybean.
Weed Technology, 2004Co-Authors: Bradley E. Fronning, George O. KegodeAbstract:Biennial wormwood has become an important weed for soybean producers in the northern Great Plains states of the United States. Research was conducted at Fargo, Leonard, and Wyndmere, ND, in 2000 and 2001 to evaluate postemergence control of biennial wormwood in soybean. Biennial wormwood densities at Fargo, Leonard, and Wyndmere were 290, 290, and 130 plants/m2 in 2000 and 22, 670, and 88 plants/m2 in 2001, respectively. Across years, biennial wormwood control with postemergence herbicides 4 wk after treatment was 81 to 97% at Fargo, 5 to 89% at Leonard, and 2 to 95% at Wyndmere. Biennial wormwood control was greater at Fargo than at the other locations probably because of smaller seedling size at the time of treatment. Bentazon split applied at the rate of 560 g ai/ha followed by 560 g/ha approximately 12 d after the first treatment generally provided the least amount of injury to soybean, the greatest control of biennial wormwood, and the fewest escaped plants. Lactofen at 220 g ai/ha or split applied a...