scholarly journals Climate Change and the Herbicide Paradigm: Visiting the Future

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1953
Author(s):  
Lewis H. Ziska
Keyword(s):  
Weed Management ◽  
Crop Production ◽  
Historical Context ◽  
Climate Impacts ◽  
Weed Biology ◽  
Evolutionary Selection ◽  
Current Perspective ◽  
Carbon Dioxide Co2 ◽  
Herbicide Use

Weeds are recognized globally as a major constraint to crop production and food security. In recent decades, that constraint has been minimized through the extensive use of herbicides in conjunction with genetically modified resistant crops. However, as is becoming evident, such a stratagem is resulting in evolutionary selection for widespread herbicide resistance and the need for a reformation of current practices regarding weed management. Whereas such a need is recognized within the traditional auspices of weed science, it is also imperative to include emerging evidence that rising levels of carbon dioxide (CO2) and climatic shifts will impose additional selection pressures that will, in turn, affect herbicide efficacy. The goal of the current perspective is to provide historical context of herbicide use, outline the biological basis for CO2/climate impacts on weed biology, and address the need to integrate this information to provide a long-term sustainable paradigm for weed management.

scholarly journals The Pitfalls of Relating Weeds, Herbicide Use, and Crop Yield: Don't Fall Into the Trap! A Critical Review

2020 ◽  
Vol 2 ◽  
Author(s):  
Nathalie Colbach ◽  
Sandrine Petit ◽  
Bruno Chauvel ◽  
Violaine Deytieux ◽  
Martin Lechenet ◽  
...  
Keyword(s):  
Crop Yield ◽  
Weed Management ◽  
Crop Production ◽  
Yield Loss ◽  
Crop Yields ◽  
Cropping Systems ◽  
Crop Productivity ◽  
Arable Farming ◽  
Herbicide Use ◽  
The Impact

The growing recognition of the environmental and health issues associated to pesticide use requires to investigate how to manage weeds with less or no herbicides in arable farming while maintaining crop productivity. The questions of weed harmfulness, herbicide efficacy, the effects of herbicide use on crop yields, and the effect of reducing herbicides on crop production have been addressed over the years but results and interpretations often appear contradictory. In this paper, we critically analyze studies that have focused on the herbicide use, weeds and crop yield nexus. We identified many inconsistencies in the published results and demonstrate that these often stem from differences in the methodologies used and in the choice of the conceptual model that links the three items. Our main findings are: (1) although our review confirms that herbicide reduction increases weed infestation if not compensated by other cultural techniques, there are many shortcomings in the different methods used to assess the impact of weeds on crop production; (2) Reducing herbicide use rarely results in increased crop yield loss due to weeds if farmers compensate low herbicide use by other efficient cultural practices; (3) There is a need for comprehensive studies describing the effect of cropping systems on crop production that explicitly include weeds and disentangle the impact of herbicides from the effect of other practices on weeds and on crop production. We propose a framework that presents all the links and feed-backs that must be considered when analyzing the herbicide-weed-crop yield nexus. We then provide a number of methodological recommendations for future studies. We conclude that, since weeds are causing yield loss, reduced herbicide use and maintained crop productivity necessarily requires a redesign of cropping systems. These new systems should include both agronomic and biodiversity-based levers acting in concert to deliver sustainable weed management.

A rotation design to reduce weed density in organic farming

2010 ◽  
Vol 25 (3) ◽  
pp. 189-195 ◽  
Author(s):  
Randy L. Anderson
Keyword(s):  
Population Dynamics ◽  
Organic Farming ◽  
Weed Management ◽  
Crop Production ◽  
Soil Health ◽  
Population Based ◽  
Weed Population ◽  
Weed Density ◽  
Organic Systems ◽  
Herbicide Use

AbstractWeeds are a major obstacle to successful crop production in organic farming. Producers may be able to reduce inputs for weed management by designing rotations to disrupt population dynamics of weeds. Population-based management in conventional farming has reduced herbicide use by 50% because weed density declines in cropland across time. In this paper, we suggest a 9-year rotation comprised of perennial forages and annual crops that will disrupt weed population growth and reduce weed density in organic systems. Lower weed density will also improve effectiveness of weed control tactics used for an individual crop. The rotation includes 3-year intervals of no-till, which will improve both weed population management and soil health. Even though this rotation has not been field tested, it provides an example of designing rotations to disrupt population dynamics of weeds. Also, producers may gain additional benefits of higher crop yield and increased nitrogen supply with this rotation design.

Changes in Herbicide Use Patterns and Production Practices Resulting from Glyphosate-Resistant Crops

2006 ◽  
Vol 20 (2) ◽  
pp. 301-307 ◽  
Author(s):  
Bryan G. Young
Keyword(s):  
Weed Management ◽  
Management Strategy ◽  
Crop Production ◽  
Large Scale ◽  
Resistance Management ◽  
Use Patterns ◽  
No Till ◽  
Production Practices ◽  
Sites Of Action ◽  
Herbicide Use

Recent shifts in herbicide use patterns can be attributed to rapid, large-scale adoption of glyphosate-resistant soybean and cotton. A dramatic increase in glyphosate use is the most obvious change associated with the adoption of glyphosate-resistant crops. Consequently, the diversity of herbicides used for weed management in these crops has declined, particularly in soybean. To date, the availability of glyphosate-resistant corn has limited the use of glyphosate in corn. While exploiting the benefits of glyphosate-resistant crops, many growers have abandoned the principles of sound weed and herbicide-resistance management. Instead of incorporating glyphosate into a resistance management strategy utilizing multiple herbicide sites of action, many growers rely exclusively upon glyphosate for weed control. Although it is difficult to establish a clear relationship between the adoption of glyphosate-resistant crops and changes in other crop production practices, the increase in no-till and strip-till production of cotton and soybean between 1995 and 2002 may have been facilitated by glyphosate-resistant crops.

An Environmental and Economic Perspective on Integrated Weed Management in Iran

2013 ◽  
Vol 27 (2) ◽  
pp. 352-361
Author(s):  
Mohammad Ghorbani ◽  
Surendra Kulshreshtha
Keyword(s):  
Weed Management ◽  
Crop Production ◽  
Wheat Yield ◽  
Multinomial Logit Model ◽  
Negative Influence ◽  
Integrated Weed Management ◽  
Number Of Factors ◽  
Wheat Cultivation ◽  
Irrigated Wheat ◽  
Herbicide Use

Inputs, including herbicides, used in crop production may create negative environmental impacts. One solution to minimize these adverse effects is the adoption of integrated weed management (IWM) with the intention of reducing herbicide use. This study, conducted in 2010, estimates the willingness of farmers to pay for the adoption of more effective weed management methods. Results suggest that the willingness to pay (WTP) for IWM is greater than the WTP for other weed management methods, including chemical weed management and chemical and mechanical weed management. This study also identified a number of factors that influence the adoption of IWM on wheat farms in Iran using a multinomial logit model. Total annual income, area under irrigated wheat, wheat yield loss due to weeds, perennial nature of the weeds, and having awareness of weed resistance to herbicides had a positive effect on the adoption of IWM practices. However, having rain-fed (dryland) wheat cultivation and a larger number of plots on the farm had a negative influence on the choice of IWM.

scholarly journals Weed management practices in natural ecosystems: a critical overview

Koedoe ◽  
2000 ◽  
Vol 43 (1) ◽  
Author(s):  
C.F. Reinhardt
Keyword(s):  
Biological Control ◽  
Weed Management ◽  
Crop Production ◽  
Management Practices ◽  
Production Systems ◽  
Management Practice ◽  
Management Tool ◽  
Natural Ecosystems ◽  
Basic Biology ◽  
Herbicide Use

Increasing public pressure against the use of pesticides and other agricultural inputs has placed increased emphasis on the development of ecologically based pest management. One distinct reaction of the Weed Science discipline has been the swing away from herbicide research to increased research on the basic biology and ecology of weeds in hopes of reduced reliance on "technological crutches" such as herbicides and other practices that are potentially harmful to the environment. Biological control is the long-standing alternative to the use of herbicides and interest in the former practice has been boosted by the realization that the use of herbicides may lead to the development of herbicide resistance in weed populations, and that herbicide residues occur in surface and groundwater. Supporters of herbicide use would point out that biological control is generally not effective in crop production systems, and is basically slow-acting. Debates between protagonists for the exclusive use of one or the other weed management practice tend to obscure the benefits that integration of different techniques are likely to have. For natural ecosystems it is proposed that integration of the more subtle practice of biological control with the use of herbicides, which relatively quickly overwhelm a biological system with mortality, is likely to be the most effective weed management tool. Different weed management practices that could be considered in natural ecosystems are discussed in terms of three key performance rating criteria, viz. activity, selec- tivity and persistence In this concise review, general discussion is focussed on the fundamentals of weed management practices, with the view to promote concept-based approaches that are critical for the development of effective weed management strate- gies.

Strategies and tactics for herbicide use reduction in field crops in Canada: A review

2005 ◽  
Vol 85 (2) ◽  
pp. 457-479 ◽  
Author(s):  
Orla M. Nazarko ◽  
Rene C. Van Acker ◽  
Martin H. Entz
Keyword(s):  
Weed Management ◽  
Crop Production ◽  
Cropping Systems ◽  
Cropping System ◽  
Integrated Weed Management ◽  
Pesticide Use ◽  
Factors Affecting ◽  
Field Crops ◽  
Low Input Agriculture ◽  
Herbicide Use

There are many economic and health reasons for reducing pesticide use in Canada. Herbicide use on field crops is by far the most common pesticide use in Canada. This paper is a review of four topics related to herbicide use reduction on field crops in Canada: (1) broad strategies and (2) specific tactics for herbicide use reduction; (3) factors affecting adoption; and 4) research approaches for improving the implementation of herbicide use reduction. Numerous tactics exist to use herbicides more efficiently and herbicides can sometimes be replaced by non-chemical weed control methods. Many of these tactics and methods have been investigated and demonstrated for use on field crops in Canada. However, herbicide use reduction is fundamentally dependent upon preventative strategies designed to create robust cropping systems that maintain low weed densities. Diverse crop rotation forms the basis of preventative strategies as it inherently varies cropping system conditions to avoid weed adaptation. There is evidence that residual weed densities resulting from herbicide use reduction are manageable within competitive cropping systems. A great deal of research has been done on herbicide use reduction on field crops in Canada, and most projects report definite possibilities for herbicide use reduction in field crop production in Canada. Synthesizing and extending this information and customizing it for use on individual farms remain challenges. Collaboration between researchers and farmers can help to build successful strategies for herbicide use reduction which reflect the context of modern farming, the will of farmers and the culture of technology adoption among farmers. Key words: Pesticide use reduction, low-input agriculture, integrated pest management, integrated weed management

scholarly journals Weed economic thresholds : Useful agronomic tool or pipe dream?

2005 ◽  
Vol 77 (1) ◽  
pp. 13-28 ◽  
Author(s):  
J.T. O’Donovan
Keyword(s):  
Weed Management ◽  
Crop Production ◽  
Production Systems ◽  
Integrated Weed Management ◽  
Practical Implementation ◽  
Weed Interference ◽  
Research Activities ◽  
Sampling Procedures ◽  
The Impact

Interest in more rational and objective approaches to weed management has increased considerably in Canada and elsewhere. Cost/benefit issues, environmental concerns, and the development of weed resistance to herbicides have cast doubt on the rationality and sustainability of prophylactic herbicide use. The concept of an economic threshold for weeds and the broader concept of integrated weed management have considerable potential as practical agronomic tools in Canadian crop production Systems. A large number of experiments have been conducted to determine the impact of weeds on crop yield, but the models developed from these studies have been put to little practical use. Constraints to the practical implementation of these concepts include a lack of realistic sampling procedures to assess the impact of weeds on crops over large areas, and a lack of information on the long-term implications of seed production by uncontrolled weeds. Weed ecologists conducting weed interference experiments should define their objectives better, and should provide guidelines on how their findings can be used at the farm level. Emphasis should be placed on the effects of the crop on the weed rather than the weed on the crop. There is also a need for greater coordination of research activities among weed ecologists. The establishment of standard protocols for long-term studies across locations and years would enhance the relevance and precision of weed interference models, and lead to the development of user- friendly decision support Systems specifically adapted to aiding rational weed management decisions in Canadian crop production Systems. The development of such Systems will be essential to the implementation of weed thresholds and integrated weed management.

Impact of long-term trials on crop production research and education

2010 ◽  
Vol 58 (Supplement 1) ◽  
pp. 1-5 ◽  
Author(s):  
M. Jolánkai ◽  
F. Nyárai ◽  
K. Kassai
Keyword(s):  
Crop Production ◽  
Life Sciences ◽  
Ecological Models ◽  
Dynamic Databases ◽  
Production Research ◽  
Research And Education

Long-term trials have a twofold role in life sciences, acting as both live laboratories and public collections. Long-term trials are not simply scientific curios or the honoured relics of a museum, but highly valuable live ecological models that can never be replaced or restarted if once terminated or suspended. These trials provide valuable and dynamic databases for solving scientific problems. The present paper is intended to give a brief summary of the crop production aspects of long-term trials.

Influence of NPK fertilization on weed flora in maize field

2014 ◽  
Vol 63 (1) ◽  
pp. 139-148 ◽  
Author(s):  
Éva Lehoczky ◽  
M. Kamuti ◽  
N. Mazsu ◽  
J. Tamás ◽  
D. Sáringer-Kenyeres ◽  
...  
Keyword(s):  
Plant Nutrition ◽  
Crop Production ◽  
N Availability ◽  
Weed Species ◽  
Negative Effects ◽  
Production Factors ◽  
Maize Field ◽  
Weed Flora ◽  
Npk Fertilization

Plant nutrition is one of the most important intensification factors of crop production. The utilization of nutrients, however, may be modified by a number of production factors, including weed presence. Thus, the knowledge of occurring weed species, their abundance, nutrient and water uptake is extremely important to establish an appropriate basis for the evaluation of their risks or negative effects on crops. That is why investigations were carried out in a long-term fertilization experiment on the influence of different nutrient supplies (Ø, PK, NK, NPK) on weed flora in maize field.The weed surveys recorded similar diversity on the experimental area: the species of A. artemisiifolia, S. halepense and D. stramonium were dominant, but C. album and C. hybridum were also common. These species and H. annuus were the most abundant weeds.Based on the totalized and average data of all treatments, density followed the same tendency in the experimental years. It was the highest in the PK treated and untreated plots, and significantly exceeded the values of NK fertilized areas. Presumably the better N availability promoted the development of nitrophilic weeds, while the mortality of other small species increased.Winter wheat and maize forecrops had no visible influence on the diversity and the intensity of weediness. On the contrary, there were consistent differences in the density of certain weed species in accordance to the applied nutrients. A. artemisiifolia was present in the largest number in the untreated control and PK fertilized plots. The density of S. halepense and H. annuus was also significantly higher in the control areas. The number of their individuals was smaller in those plots where N containing fertilizers were used. Contrary to them, the density of D. stramonium, C. album and C. hybridum was the highest in the NPK treatments.

Liberating Afghan Women

2004 ◽  
Vol 21 (3) ◽  
pp. 70-88 ◽  
Author(s):  
Nancy Gallagher
Keyword(s):  
United States ◽  
Human Rights ◽  
Historical Context ◽  
The United States ◽  
Political Organizations ◽  
Way Of Life ◽  
Afghan Women ◽  
The Media ◽  
Policy Priority

Public opinion in the United States and elsewhere celebrated the liberation of Afghan women following the defeat of the Taliban government. The United States promised to stay in Afghanistan and foster security, economic development, and human rights for all, especially women. After years of funding various anti- Soviet Mujahidin warlords, the United States had agreed to help reconstruct the country once before in 1992, when the Soviet-backed government fell, but had lost interest when the warlords began to fight among themselves. This time, however, it was going to be different. To date, however, conditions have not improved for most Afghan women and reconstruction has barely begun. How did this happen? This article explores media presentations of Afghan women and then compares them with recent reports from human rights organizations and other eyewitness accounts. It argues that the media depictions were built on earlier conceptions of Muslim societies and allowed us to adopt a romantic view that disguised or covered up the more complex historical context of Afghan history and American involvement in it. We allowed ourselves to believe that Afghans were exotic characters who were modernizing or progressing toward a western way of life, despite the temporary setback imposed by the Taliban government. In Afghanistan, however, there was a new trope: the feminist Afghan woman activist. Images of prominent Afghan women sans burqa were much favored by the mass media and American policymakers. The result, however, was not a new focus on funding feminist political organizations or making women’s rights a foreign policy priority; rather, it was an unwillingness to fulfill obligations incurred during decades of American-funded mujahidin warfare, to face the existence of deteriorating conditions for women, resumed opium cultivation, and a resurgent Taliban, or to commit to a multilateral approach that would bring in the funds and expertise needed to sustain a long-term process of reconstruction.

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