Slowing weed evolution with integrated weed management

2013 ◽  
Vol 93 (5) ◽  
pp. 759-764 ◽  
Author(s):  
K. N. Harker
Keyword(s):  
Weed Management ◽  
Crop Production ◽  
Crop Yields ◽  
Cropping Systems ◽  
Cropping System ◽  
Integrated Weed Management ◽  
Research Knowledge ◽  
Weed Evolution ◽  
System Sustainability ◽  
Weed Resistance

Harker, K. N. 2013. Slowing weed evolution with integrated weed management. Can. J. Plant Sci. 93: 759–764. For millennia, weeds have slowly evolved in response to ever-changing environments and crop production practices. Weeds are now evolving much more quickly due to consistently repeated cropping systems and intense herbicide selection pressures. Weed resistance to herbicides now threatens cropping system sustainability in several industrialized nations. Integrated weed management (IWM) provides opportunities to reduce selection pressure for weed resistance while maintaining current crop yields. Combining optimal IWM tactics that discourage weeds by minimizing disturbance (no till, direct-seeding), adopting diverse crop rotations, and attempting to preclude resource acquisition by weeds are encouraged. New research knowledge on practical IWM systems is available, but despite current and looming threats of major weed resistance, most crop producers will require greater incentives than those currently available to more-fully adopt IWM systems in the near future.

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 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.

scholarly journals Weeds and Their Effect on the Performance of Maize and Finger Millet in Mid-Hills of Nepal

2014 ◽  
Vol 2 (3) ◽  
pp. 275-278 ◽  
Author(s):  
Tika Bahadur Karki ◽  
Shrawan K. Sah ◽  
Resam B. Thapa ◽  
Andrew J. McDonald ◽  
Adam S. Davis ◽  
...  
Keyword(s):  
Weed Management ◽  
Crop Production ◽  
Finger Millet ◽  
Crop Yields ◽  
Management Strategies ◽  
Cropping System ◽  
Weed Species ◽  
Ageratum Conyzoides ◽  
Alternative Crop ◽  
Weed Infestation

Relay cropping of maize with fingermillet (maize/fingermillet) is the predominant cropping system for sustaining food security situation in the hilly regions of Nepal. In this region weed pressure severely reduces crop yields. Basic information on weed species composition, biomass production and their effect on crop yields and economics are lacking for this region. This information will be necessary to develop effective weed management strategies for the future. In light of this an empirical study was carried out in two representatives mid hill districts of Parbat and Baglung during summer season of 2010/2011 in Nepal. A total of 10 major weed species with densities of 172 in Parbat and 311 per 0.25m2 area in Baglung were observed. The highest percentage of both relative and absolute densities were recorded for Ageratum conyzoides in Parbat and Polygonum chinensis in Baglung. Weed infestation under farmers practice of crop management reduced the grain yield of maize by 1.985 Mt ha-1 (117%) in Baglung and 1.760 Mt ha-1 (108%) in Parbat. Similarly, in finger millet it was 0.489 Mt ha-1 (63%) in Baglung and 0.403 Mt ha-1 in Parbat. Similarly, the combined yield of both the crops was also significantly reduced by 79.3% and 61.7% in Baglung and Parbat respectively. Hence, weeds are directly affecting the crop performance in the region. Therefore, there is an urgent need to develop an alternative crop production system in the hills. DOI: http://dx.doi.org/10.3126/ijasbt.v2i3.10790Int J Appl Sci Biotechnol, Vol. 2(3): 275-278  

scholarly journals Effect of Cropping System and Rice Residue Retention on Crop Productivity and Soil Physical Properties in Rice Based Cropping System of Bangladesh

2019 ◽  
Vol 17 (1-2) ◽  
pp. 14-30
Author(s):  
M Jahangir Alam ◽  
S Ahmed ◽  
MK Islam ◽  
R Islam ◽  
M Islam
Keyword(s):  
Crop Production ◽  
Crop Yields ◽  
Cropping Systems ◽  
Wheat Yield ◽  
Cropping System ◽  
Physical Property ◽  
Crop Productivity ◽  
System Productivity ◽  
Transplanted Rice ◽  
Residue Retention

Cropping systems of Bangladesh are highly diverse and cultivation costs of puddled transplanted rice (PTR) are high. Therefore, an improved system is needed to address the issues, a field experiment was conducted during 2011-2013 to evaluate system intensification with varying degrees of cropping systems and residue retention. Four cropping systems (CSE) namely CSE1: T. boro rice-T. aman rice (control), CSE2: wheat-mungbean-T. aman rice (wheat and mungbean sown using a power tiller-operated seeder (PTOS) with full tillage in a single pass; puddled transplanted aman), CSE3: wheat-mungbean-dry seeded DS aman rice (DSR), and CSE4: wheat-mungbean-DS aman rice (all sown by PTOS with strip tillage) were compared. Two levels of aman rice residue retention (removed; partial retention i.e. 40 cm of standing stubble) were compared in sub plots. Grain yield was significantly higher (by 11%) when wheat was grown after DSR than PTR. Similarly, PTR and DSR (aman rice) produced statistically similar crop yields. Rice residue retention resulted a significantly higher (by 10%) wheat yield and a slightly increased (by 6%) mungbean yield than that of residues removed. The system productivity of CSE4 was significantly higher (by 10%) than CSE1 when averaged of the two years data. Partial aman residue retention gave significantly higher system yield than residue removal (by 0.6 t ha-1). After two years, no effect of CSE or partial aman residue retention was found on soil physical property (bulk density) of the top soil. Therefore, CSE4 along with residue retention would be more effective for sustainable crop production. The Agriculturists 2019; 17(1-2) 14-30

Cropping Systems in Some Drought-Prone Communities of the Northern Region of Ghana: Factors Affecting the Introduction of Rice

2014 ◽  
Vol 9 (4) ◽  
pp. 475-483 ◽  
Author(s):  
Vincent Kodjo Avornyo ◽  
◽  
Osamu Ito ◽  
Gordana Kranjac-Berisavljevic ◽  
Osamu Saito ◽  
...  
Keyword(s):  
Crop Production ◽  
Crop Yields ◽  
Cropping Systems ◽  
Average Distance ◽  
Cropping System ◽  
Principal Component ◽  
Northern Region ◽  
Northern Ghana ◽  
Cattle Production ◽  
Factors Affecting

Despite the growing demand for rice in Ghana, domestic rice production remains low, resulting in the importation of about 70% of the rice consumed in Ghana. In spite of the fact that 39-47% of the 20-28% of Ghana’s total geographic area classified as inland valley wetlands is considered suitable for rice cultivation, less than 15% is presently being used. A household survey was therefore conducted in six communities, Fihini (F), Cheshegu (C), Dabogushei (D), Kpalgum (K), Zergua (Z), and Yoggu (Y), of the Tolon district in northern Ghana in order to identify factors affecting the introduction of rice into the cropping system. Maize, groundnut, rice, and yam were found to be the four major crops grown in the communities. Overall, 64% of respondents cultivate rice, but this figure is particularly low (30%) in F and Y communities. Rice is usually combined with two other major crops, most frequently maize and yam. In C, D, and K communities, about 90% of households cultivate at least, three out of the four major crops. The interview with farmers revealed that rice yield is 0.73 t/ha on average and significantly higher in K and C (1.06 t/ha and 0.93 t/ha, respectively) than in D (0.37 t/ha). The average distance from compound houses to rice and maize fields is significantly shorter in C, D, and K. Similarly, the rate of rice introduction in C, D, and K is higher than in F, Z, and Y, suggesting that distance to inland valleys may be one of the factors that influence the incorporation of rice into the cropping systems of these communities. Principal component analysis of crop yields and cattle number for the Y community revealed that rice growers tend to have higher crop productivity while cattle production is higher among non-rice growers. Within the community, the productivity of upland crops and balance between crop production and cattle production may be important factors that influence the incorporation of rice into the cropping system.

scholarly journals Emerging Challenges for Weed Management in Herbicide-Resistant Crops

Agriculture ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 180 ◽  
Author(s):  
Karla L. Gage ◽  
Ronald F. Krausz ◽  
S. Alan Walters
Keyword(s):  
Weed Management ◽  
Selection Pressure ◽  
New Technologies ◽  
Cropping Systems ◽  
Critical Role ◽  
Cropping System ◽  
Herbicide Resistant ◽  
Increased Risk ◽  
Sites Of Action ◽  
Weed Resistance

Since weed management is such a critical component of agronomic crop production systems, herbicides are widely used to provide weed control to ensure that yields are maximized. In the last few years, herbicide-resistant (HR) crops, particularly those that are glyphosate-resistant, and more recently, those with dicamba (3,6-dichloro-2-methoxybenzoic acid) and 2,4-D (2,4-dichlorophenoxyacetic acid) resistance are changing the way many growers manage weeds. However, past reliance on glyphosate and mistakes made in stewardship of the glyphosate-resistant cropping system have directly led to the current weed resistance problems that now occur in many agronomic cropping systems, and new technologies must be well-stewarded. New herbicide-resistant trait technologies in soybean, such as dicamba-, 2,4-D-, and isoxaflutole- ((5-cyclopropyl-4-isoxazolyl)[2-(methylsulfonyl)-4-(trifluoromethyl)phenyl]methanone) resistance, are being combined with glyphosate- and glufosinate-resistance traits to manage herbicide-resistant weed populations. In cropping systems with glyphosate-resistant weed species, these new trait options may provide effective weed management tools, although there may be increased risk of off-target movement and susceptible plant damage with the use of some of these technologies. The use of diverse weed management practices to reduce the selection pressure for herbicide-resistant weed evolution is essential to preserve the utility of new traits. The use of herbicides with differing sites of action (SOAs), ideally in combination as mixtures, but also in rotation as part of a weed management program may slow the evolution of resistance in some cases. Increased selection pressure from the effects of some herbicide mixtures may lead to more cases of metabolic herbicide resistance. The most effective long-term approach for weed resistance management is the use of Integrated Weed Management (IWM) which may build the ecological complexity of the cropping system. Given the challenges in management of herbicide-resistant weeds, IWM will likely play a critical role in enhancing future food security for a growing global population.

scholarly journals Agricultural Innovation and Sustainable Development: A Case Study of Rice–Wheat Cropping Systems in South Asia

2021 ◽  
Vol 13 (4) ◽  
pp. 1965
Author(s):  
Aman Ullah ◽  
Ahmad Nawaz ◽  
Muhammad Farooq ◽  
Kadambot H. M. Siddique
Keyword(s):  
South Asia ◽  
Precision Agriculture ◽  
Weed Management ◽  
Crop Yields ◽  
Cropping Systems ◽  
Cropping System ◽  
Climatic Conditions ◽  
Transplanted Rice ◽  
Direct Seeded ◽  
Rice Residues

The rice–wheat cropping system is the main food bowl in Asia, feeding billions across the globe. However, the productivity and long-term sustainability of this system are threatened by stagnant crop yields and greenhouse gas emissions from flooded rice production. The negative environmental consequences of excessive nitrogen fertilizer use are further exacerbating the situation, along with the high labor and water requirements of transplanted rice. Residue burning in rice has also severe environmental concerns. Under these circumstances, many farmers in South Asia have shifted from transplanted rice to direct-seeded rice and reported water and labor savings and reduced methane emissions. There is a need for opting the precision agriculture techniques for the sustainable management of nutrients. Allelopathic crops could be useful in the rotation for weed management, the major yield-reducing factor in direct-seeded rice. Legume incorporation might be a viable option for improving soil health. As governments in South Asia have imposed a strict ban on the burning of rice residues, the use of rice-specific harvesters might be a pragmatic option to manage rice residues with yield and premium advantage. However, the soil/climatic conditions and farmer socio-economic conditions must be considered while promoting these technologies in rice-wheat system in South Asia.

U.S. Grower Views on Problematic Weeds and Changes in Weed Pressure in Glyphosate-Resistant Corn, Cotton, and Soybean Cropping Systems

2009 ◽  
Vol 23 (1) ◽  
pp. 162-166 ◽  
Author(s):  
Greg R. Kruger ◽  
William G. Johnson ◽  
Stephen C. Weller ◽  
Micheal D. K. Owen ◽  
David R. Shaw ◽  
...  
Keyword(s):  
North Carolina ◽  
Weed Management ◽  
Cropping Systems ◽  
Cropping System ◽  
The State ◽  
Integrated Weed Management ◽  
Management Tactics

Corn and soybean growers in Illinois, Indiana, Iowa, Mississippi, Nebraska, and North Carolina, as well as cotton growers in Mississippi and North Carolina, were surveyed about their views on changes in problematic weeds and weed pressure in cropping systems based on a glyphosate-resistant (GR) crop. No growers using a GR cropping system for more than 5 yr reported heavy weed pressure. Over all cropping systems investigated (continuous GR soybean, continuous GR cotton, GR corn/GR soybean, GR soybean/non-GR crop, and GR corn/non-GR crop), 0 to 7% of survey respondents reported greater weed pressure after implementing rotations using GR crops, whereas 31 to 57% felt weed pressure was similar and 36 to 70% indicated that weed pressure was less. Pigweed, morningglory, johnsongrass, ragweed, foxtail, and velvetleaf were mentioned as their most problematic weeds, depending on the state and cropping system. Systems using GR crops improved weed management compared with the technologies used before the adoption of GR crops. However, the long-term success of managing problematic weeds in GR cropping systems will require the development of multifaceted integrated weed management programs that include glyphosate as well as other weed management tactics.

Environmental Effects on the Relative Competitive Ability of Canola and Small-Grain Cereals in a Direct-Seeded System

Weed Science ◽  
2011 ◽  
Vol 59 (3) ◽  
pp. 404-415 ◽  
Author(s):  
K. Neil Harker ◽  
John T. O'Donovan ◽  
Robert E. Blackshaw ◽  
Eric N. Johnson ◽  
Frederick A. Holm ◽  
...  
Keyword(s):  
Weed Management ◽  
Competitive Ability ◽  
Cropping System ◽  
Integrated Weed Management ◽  
Canadian Prairies ◽  
Barley Cultivars ◽  
Direct Seeded ◽  
Competitive Species ◽  
System Sustainability ◽  
High Level

Growing crops that exhibit a high level of competition with weeds increases opportunities to practice integrated weed management and reduce herbicide inputs. The recent development and market dominance of hybrid canola cultivars provides an opportunity to reassess the relative competitive ability of canola cultivars with small-grain cereals. Direct-seeded (no-till) experiments were conducted at five western Canada locations from 2006 to 2008 to compare the competitive ability of canola cultivars vs. small-grain cereals. The relative competitive ability of the species and cultivars was determined by assessing monocot and dicot weed biomass at different times throughout the growing season as well as oat (simulated weed) seed production. Under most conditions, but especially under warm and relatively dry environments, barley cultivars had the greatest relative competitive ability. Rye and triticale were also highly competitive species under most environmental conditions. Canada Prairie Spring Red wheat and Canada Western Red Spring wheat cultivars usually were the least competitive cereal crops, but there were exceptions in some environments. Canola hybrids were more competitive than open-pollinated canola cultivars. More importantly, under cool, low growing degree day conditions, canola hybrids were as competitive as barley, especially with dicot weeds. Under most conditions, hybrid canola growers on the Canadian Prairies are well advised to avoid the additional selection pressure inherent with a second in-crop herbicide application. Combining competitive cultivars of any species with optimal agronomic practices that facilitate crop health will enhance cropping system sustainability and allow growers to extend the life of their valuable herbicide tools.

scholarly journals Recent Weed Control, Weed Management, and Integrated Weed Management

2013 ◽  
Vol 27 (1) ◽  
pp. 1-11 ◽  
Author(s):  
K. Neil Harker ◽  
John T. O'Donovan
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Crop Production ◽  
Management Practices ◽  
Cropping Systems ◽  
Arable Land ◽  
The United States ◽  
Integrated Weed Management ◽  
Negative Consequences ◽  
Research Activity

Integrated weed management (IWM) can be defined as a holistic approach to weed management that integrates different methods of weed control to provide the crop with an advantage over weeds. It is practiced globally at varying levels of adoption from farm to farm. IWM has the potential to restrict weed populations to manageable levels, reduce the environmental impact of individual weed management practices, increase cropping system sustainability, and reduce selection pressure for weed resistance to herbicides. There is some debate as to whether simple herbicidal weed control programs have now shifted to more diverse IWM cropping systems. Given the rapid evolution and spread of herbicide-resistant weeds and their negative consequences, one might predict that IWM research would currently be a prominent activity among weed scientists. Here we examine the level of research activity dedicated to weed control techniques and the assemblage of IWM techniques in cropping systems as evidenced by scientific paper publications from 1995 to June 1, 2012. Authors from the United States have published more weed and IWM-related articles than authors from any other country. When IWM articles were weighted as a proportion of country population, arable land, or crop production, authors from Switzerland, the Netherlands, New Zealand, Australia, and Canada were most prominent. Considerable evidence exists that research on nonherbicidal weed management strategies as well as strategies that integrate other weed management systems with herbicide use has increased. However, articles published on chemical control still eclipse any other weed management method. The latter emphasis continues to retard the development of weed science as a balanced discipline.

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