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.

Weed management: fact or fable?

1981 ◽  
Vol 295 (1076) ◽  
pp. 185-197 ◽  
Keyword(s):  
Weed Control ◽  
Growth Regulators ◽  
Weed Management ◽  
Crop Production ◽  
Management Practices ◽  
Production Systems ◽  
Cropping System ◽  
Ground Cover ◽  
Management Approach ◽  
Leguminous Crops

Weed management is a new term for the age-old practice of employing all available means, in a planned way, to keep weed populations under control. It seeks to distinguish the systematic approach to weed control, based on scientific knowledge and rational strategies, from the pragmatic destruction of weeds. The remarkable efficiency of herbicides has in recent years emphasized the latter and allowed revolutionary methods of crop production to be practised. These have, however, led to serious new weed problems which in turn require more intensive herbicide use. The need for a weed management approach is increasingly recognized. New opportunities for this are provided by the availability of numerous herbicides and plant growth regulators and a growing understanding of the biology, ecology and population dynamics of weeds in relation to crop production systems. Examples discussed include: systematic control of grass weeds in intensive cereals in Britain, weed control in rice and in soybeans, the control of aquatic weeds by biological and chemical methods and an experimental zero-tillage cropping system for the humid tropics based on herbicides, growth regulators and ground-cover leguminous crops. In such management systems, interference of weed behaviour by exogenous growth regulators is likely to be of increasing significance. Constraints on the adoption of weed management practices include lack of support for weed science as a discipline, limited appeal to the agrochemical industry and inadequate extension services in many countries.

scholarly journals Reducing the Risks of Herbicide Resistance: Best Management Practices and Recommendations

Weed Science ◽  
2012 ◽  
Vol 60 (SP1) ◽  
pp. 31-62 ◽  
Author(s):  
Jason K. Norsworthy ◽  
Sarah M. Ward ◽  
David R. Shaw ◽  
Rick S. Llewellyn ◽  
Robert L. Nichols ◽  
...  
Keyword(s):  
Weed Control ◽  
Herbicide Resistance ◽  
Best Management Practices ◽  
Weed Management ◽  
Crop Production ◽  
Management Practices ◽  
Production Systems ◽  
Herbicide Resistant ◽  
Economic Thresholds ◽  
Soil Seedbank

Herbicides are the foundation of weed control in commercial crop-production systems. However, herbicide-resistant (HR) weed populations are evolving rapidly as a natural response to selection pressure imposed by modern agricultural management activities. Mitigating the evolution of herbicide resistance depends on reducing selection through diversification of weed control techniques, minimizing the spread of resistance genes and genotypes via pollen or propagule dispersal, and eliminating additions of weed seed to the soil seedbank. Effective deployment of such a multifaceted approach will require shifting from the current concept of basing weed management on single-year economic thresholds.

Introduction to the Symposium: History of Sulfonylurea Herbicide Use in Turfgrass Environments

2012 ◽  
Vol 26 (3) ◽  
pp. 575-578 ◽  
Author(s):  
Prasanta C. Bhowmik
Keyword(s):  
Weed Management ◽  
Management Practices ◽  
Production Systems ◽  
Warm Season ◽  
Current Status ◽  
Selective Control ◽  
History Of ◽  
Research Findings ◽  
Potential Benefits ◽  
Herbicide Use

Weed management is a common practice in golf courses, home lawns, and sod production systems. Sulfonylurea (SU) herbicides were initially introduced in the agricultural market in 1982; however, SUs were also evaluated for control of weeds and overseeded grasses. Later, SUs were evaluated for selective control of broadleaf weeds, sedges, and kyllinga species in cool- and warm-season turfgrasses. In the 1990s, chlorsulfuron and metsulfuron were registered for selective control of broadleaf weeds, such as wild garlic, spotted spurge, and difficult-to-control grasses, such as bahiagrass in turfgrass. Now, there are several SUs registered for specific weed management in both cool- and warm-season turfgrasses. The current status of SUs, along with potential benefits and drawbacks in using these herbicides for weed management practices, are discussed. The research findings, possible recommendations in relation to the safety of turfgrass (established and overseeding stands), environmental concerns (persistence and lateral movement), and management practices in cool- and warm-season turfgrasses are discussed, including the potential evolution of weed resistance.

Toward Reduced Herbicide Rates and Adapted Weed Management

1994 ◽  
Vol 8 (2) ◽  
pp. 376-386 ◽  
Author(s):  
Andreas Zoschke
Keyword(s):  
Weed Management ◽  
Management Practices ◽  
Systems Approach ◽  
Cultural Practices ◽  
Production Systems ◽  
Management Practice ◽  
Cropping Systems ◽  
Critical Discussion ◽  
Weed Dynamics ◽  
Low Rate

Herbicides are an integral part of farmers' cultural practices worldwide. Growing concerns about agrochemical residues in the environment and in the food supply require a critical discussion about how to secure the environmental fitness of any weed management practice. Promising ways to minimize herbicide consumption include the introduction of new (low-rate) chemistries, the low-rate concept, innovative formulations, application timing, and a cropping systems approach. However, many questions with regard to crop/weed dynamics in different agricultural production systems require answers before final recommendations can be made, and the farmer has to occupy a central part of our considerations. Besides conducting more basic weed research to reduce herbicide rates, it will be equally important to integrate the efforts of all parties involved and to improve the communication with our customers, including the public, environmental interest groups, and politicians. To be widely accepted, weed management practices for the future have to be adapted such that the respective requirements of environment, society, and economics are fully met.

scholarly journals Rhizobacteria as Biocontrol Agents of Weeds

1996 ◽  
Vol 10 (3) ◽  
pp. 601-609 ◽  
Author(s):  
Robert J. Kremer ◽  
Ann C. Kennedy
Keyword(s):  
Biological Control ◽  
Weed Control ◽  
Weed Management ◽  
Management Practices ◽  
Field Studies ◽  
Biocontrol Agents ◽  
Residue Management ◽  
Weed Growth ◽  
Deleterious Rhizobacteria ◽  
Herbicide Use

There is a current need to develop alternative weed management techniques in response to demands for reduction in herbicide use due mainly to health and environmental concerns. Therefore, all possible nonchemical strategies for weed control should be considered, including biological control. Deleterious rhizobacteria (DRB), largely overlooked as potential biological control agents for weeds until recently, are able to colonize root surfaces of weed seedlings and suppress plant growth. Limited field studies indicate that DRB suppressed weed growth, and reduced weed density, biomass, and seed production. In this manner, crops out-compete the suppressed weeds for growth requirements, eliminating the necessity for eradication of weeds in the crop. Establishment of DRB as a viable biological control strategy initially will require integration with other weed control approaches including other biocontrol agents, agrichemicals, and cultural and residue management practices. To achieve success, more in-depth research is needed on ecology of bacteria-plant relationships, mechanisms of action (including characterization of phytotoxins), inocula formulations, and methods to enhance crop competition.

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 Survey of Glyphosate-Resistant Waterhemp (Amaranthus rudis) in Missouri Soybean Fields and Prediction of Glyphosate Resistance in Future Waterhemp Populations Based on In-Field Observations and Management Practices

2013 ◽  
Vol 27 (4) ◽  
pp. 656-663 ◽  
Author(s):  
Kristin K. Rosenbaum ◽  
Kevin W. Bradley
Keyword(s):  
Crop Production ◽  
Management Practices ◽  
Production Systems ◽  
Glyphosate Resistance ◽  
Continuous Cropping ◽  
Field Observations ◽  
Weed Species ◽  
Herbicide Treatment ◽  
Amaranthus Rudis

A survey of soybean fields containing waterhemp infestations was conducted just prior to harvest in 2008 and 2009 to determine the frequency and distribution of glyphosate-resistant waterhemp in Missouri, and to determine if there are any in-field parameters that may serve as indicators of glyphosate resistance in this species in future crop production systems. Glyphosate resistance was confirmed in 99 out of 144, or 69%, of the total waterhemp populations sampled, which occurred in 41 counties of Missouri. Populations of glyphosate-resistant waterhemp were more likely to occur in fields with no other weed species present at the end of the season, continuous cropping of soybean, exclusive use of glyphosate for several consecutive seasons, and waterhemp plants showing obvious signs of surviving herbicide treatment compared to fields characterized with glyphosate-susceptible waterhemp. Therefore, it is suggested that these four site parameters, and certain combinations of these parameters, serve as predictors of glyphosate resistance in future waterhemp populations.

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.

scholarly journals Surface lime and silicate application and crop production system effects on physical characteristics of a Brazilian Oxisol

Soil Research ◽  
2017 ◽  
Vol 55 (8) ◽  
pp. 778
Author(s):  
G. S. A. Castro ◽  
C. A. C. Crusciol ◽  
C. A. Rosolem ◽  
J. C. Calonego ◽  
K. R. Brye
Keyword(s):  
Physical Properties ◽  
Bulk Density ◽  
Production System ◽  
Crop Production ◽  
Management Practices ◽  
Production Systems ◽  
Crop Productivity ◽  
Soil Physical Properties ◽  
Physical Characteristics ◽  
Forage Crop

This work aimed to evaluate the effects of crop rotations and soil acidity amelioration on soil physical properties of an Oxisol (Rhodic Ferralsol or Red Ferrosol in the Australian Soil Classification) from October 2006 to September 2011 in Botucatu, SP, Brazil. Treatments consisted of four soybean (Glycine max)–maize (Zea mays)–rice (Oryza sativa) rotations that differed in their off-season crop, either a signal grass (Urochloa ruziziensis) forage crop, a second crop, a cover crop, or fallow. Two acid-neutralising materials, dolomitic lime (effective calcium carbonate equivalent (ECCE) = 90%) and calcium-magnesium silicate (ECCE = 80%), were surface applied to raise the soil’s base saturation to 70%. Selected soil physical characteristics were evaluated at three depths (0–0.1, 0.1–0.2, and 0.2–0.4 m). In the top 0.1 m, soil bulk density was lowest (P < 0.05) and macroporosity and aggregate stability index were greatest (P < 0.05) in the forage crop compared with all other production systems. Also, bulk density was lower (P < 0.05) and macroporosity was greater (P < 0.05) in the acid-neutralising-amended than the unamended control soil. In the 0.1–0.2-m interval, mean weight diameter and mean geometric diameter were greater (P < 0.05) in the forage crop compared with all other production systems. All soil properties evaluated in this study in the 0.2–0.4-m interval were unaffected by production system or soil amendment after five complete cropping cycles. Results of this study demonstrated that certain soil physical properties can be improved in a no-tillage soybean–maize–rice rotation using a forage crop in the off-season and with the addition of acid-neutralising soil amendments. Any soil and crop management practices that improve soil physical properties will likely contribute to sustaining long-term soil and crop productivity in areas with highly weathered, organic matter-depleted, acidic Oxisols.

Weed management practices in glyphosate-tolerant and conventional cotton fields in Australia

2006 ◽  
Vol 46 (9) ◽  
pp. 1177 ◽  
Author(s):  
J. A. Werth ◽  
C. Preston ◽  
G. N. Roberts ◽  
I. N. Taylor
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Management Practices ◽  
Herbicide Application ◽  
Resistance Development ◽  
Roundup Ready ◽  
Use Patterns ◽  
Management Techniques ◽  
Cotton Fields ◽  
Herbicide Use

Forty growers in 4 major cotton-growing regions in Australia were surveyed in 2003 to investigate how the adoption of glyphosate-tolerant cotton (Roundup Ready) had influenced herbicide use, weed management techniques, and whether changes to the weed spectrum could be identified. The 10 most common weeds reported on cotton fields were the same in glyphosate-tolerant and conventional fields in this survey. Herbicide use patterns were altered by the adoption of glyphosate-tolerant cotton with up to 6 times more glyphosate usage, but 21% fewer growers applying pre-emergence herbicides in glyphosate-tolerant fields. Other weed control practices such as the use of post-emergence herbicides, inter-row cultivation and hand hoeing were only reduced marginally. However, growers indicated that management practices are likely to change over time, especially with the introduction of enhanced glyphosate tolerance technology (Roundup Ready Flex), and anticipate a 32% decrease in the number of growers using alternative weed management practices. To date, management practices other than glyphosate use have not changed markedly in glyphosate-tolerant cotton indicating a conservative approach by growers adopting this technology and reflecting the narrow window of herbicide application. The range of weed control options still being employed in glyphosate-tolerant cotton would not increase the risk of glyphosate resistance development.

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