Weed regulation by crop and grassland competition: critical biomass level and persistence rate

AbstractIt is widely agreed that competition regulates plant populations and shapes communities. Many studies have suggested that crop and grassland competition can be used for cost-effective sustainable weed control. However, effective weed management requires a precise knowledge of the effects of agronomic practices and there is a lack of quantitative indicators to compare and predict the success of weed biocontrol by competition.We studied weed abundance dynamics over a 12-year period in crop-grassland rotations (rotation treatments consisted of maize, wheat and barley crops, alternating with temporary grassland maintained for three or six years in the rotation and fertilised with two different levels of nitrogen). In addition to classical statistical analysis of the different aforementioned rotation treatments, we also modelled weed abundance as a function of the crop and grassland competition, expressed here by biomasses harvested in the preceding years.We show that weed abundance decreases over the years in grassland and subsequent crops only if the grassland receives sufficient nitrogen fertiliser. Our model had a much greater explanatory power than the rotation treatments. This model estimates a critical biomass level above which weeds are suppressed in subsequent years, and below which they tend to thrive. This critical biomass level was 24.3 and 4.7 tonnes ha−1 of dry matter for crops and grassland, respectively, highlighting the greater competitiveness of grasslands than of crops. Several clear differences between weed functional groups emerged.Synthesis and applications - This new modelling approach directly links the interannual dynamics of weed populations to current and previous biomass production levels. This approach facilitates the development of environment-friendly weed management strategies and paves the way for comparisons of the competitiveness against weeds of crops and grassland under various pedoclimatic conditions and agronomic practices.

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Weed Management in New Zealand Pastures

Agronomy ◽

10.3390/agronomy9080448 ◽

2019 ◽

Vol 9 (8) ◽

pp. 448 ◽

Cited By ~ 7

Author(s):

Hossein Ghanizadeh ◽

Kerry C. Harrington

Keyword(s):

New Zealand ◽

Weed Management ◽

Management Strategies ◽

Cost Effective ◽

Integrated Weed Management ◽

Meat Production ◽

Weed Species ◽

Pasture Management ◽

Pasture Production ◽

Important Approach

In New Zealand, pastoral farming for dairy and meat production is the major land use. As with any agricultural production system, weeds are a threat to efficient pasture production in New Zealand. In this review, we outline the problems caused by weeds in New Zealand pastures, and the management strategies being used to control them. There are currently 245 plant species from 40 plant families that are considered to be troublesome weeds in New Zealand pastures. The application of herbicides is an important approach to manage weeds in New Zealand pastures; however, a key to the success of these pastures is the use of clovers in combination with the grasses, so the challenge is to find herbicides that selectively control weeds without damaging these legumes. The use of spot spraying and weed wiping are often required to ensure selective control of some weed species in these pastures. Non-chemical agronomic approaches such as grazing management and using competitive pasture species often play a more important role than herbicides for weed management in many New Zealand pastures. Thus, integrated weed management using a combination of herbicides and good pasture management strategies leads to the most cost-effective and efficient control of pasture weeds in New Zealand.

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An assessment of weed flora 14 years after the introduction of glyphosate-tolerant cotton in Australia

Crop and Pasture Science ◽

10.1071/cp17116 ◽

2017 ◽

Vol 68 (8) ◽

pp. 773 ◽

Cited By ~ 21

Author(s):

Sudheesh Manalil ◽

Jeff Werth ◽

Rod Jackson ◽

Bhagirath Singh Chauhan ◽

Christopher Preston

Keyword(s):

Weed Management ◽

Management Strategies ◽

Cost Effective ◽

Sesbania Cannabina ◽

Management Options ◽

South Wales ◽

Weed Population Dynamics ◽

Conyza Bonariensis ◽

Chloris Virgata ◽

And Shifts

Glyphosate-tolerant (GT) cotton offers a multitude of benefits such as broad-spectrum and cost-effective weed control, simple weed management, and reduced impact on the environment. However, high adoption rates of GT cotton have led to overreliance on glyphosate in weed management and have decreased the use of other herbicide options and non-chemical weed-management strategies, possibly leading to the emergence of many resistant weeds. Previous surveys in 2006 and 2011 in the cotton-growing regions of New South Wales (NSW) and Queensland, Australia, indicated changes in weed populations over the period and increased prevalence of several weeds. These two surveys indicated increased dominance of Conyza bonariensis, Echinochloa colona, and Chloris virgata in these regions. Periodic weed surveys are necessary to assess weed population dynamics and shifts due to overreliance on glyphosate for weed management. A survey was carried out in the cotton-growing regions of NSW and Queensland in 2014–15, covering 135 fields. Survey results indicated the emergence of volunteer GT cotton as the most common weed present across all of the cotton-growing regions, occurring in 85% of fields, followed by E. colona (67% of fields surveyed), and C. bonariensis and Sonchus oleraceus, which were present in 51% of fields. The most prevalent grass weed after E. colona was C. virgata (37%). Broadleaf weeds Ipomoea lonchophylla and Amaranthus mitchellii were present in 40% and 37% of fields, respectively. Regional-level analysis indicated greater prevalence of Sesbania cannabina and Parthenium hysterophorus in Emerald region of Queensland. Lolium rigidum was present in the Griffith and Warren area of NSW during summer, even though it is a winter weed. The results of this study indicate integration of diversified weed-management options and inclusion of both non-chemical and chemical options because many major weeds observed in this study are tolerant to glyphosate and have already evolved resistance to glyphosate.

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Integrated Weed Management Strategies for Sustainable Rice Production in Bangladesh

Bangladesh Rice Journal ◽

10.3329/brj.v24i2.53454 ◽

2021 ◽

Vol 24 (2) ◽

pp. 133-159

Author(s):

MKA Bhuiyan ◽

MU Salam ◽

MS Kabir

Keyword(s):

Weed Management ◽

Yield Loss ◽

Proper Time ◽

Management Strategies ◽

Cost Effective ◽

Science Research ◽

Rice Production ◽

Integrated Weed Management ◽

Agricultural System ◽

Hand Weeding

Weed causes huge reduction in crops yield, increases cost of cultivation, reduces input efficiency, interferes with agricultural operations, impairs quality, act as alternate hosts for several insect and diseases .Yield loss due to improper weeding at farmer’s field ranged from 4 to 22% depending on different rice ecosystem in Bangladesh. But at present considering all the cultivable land across the country and other issues; yield loss due to weeds considered about 2% in a consultation meeting.The present weed control practices in Bangladesh are characterized by intensive use of manual labour, use of herbicide and certain mechanical weeding. Manual weeding, besides laborious is inefficient as it is not done in time in most of the cases and always not practical because of various adverse conditions. Cost effective and integrated weed management system should be adopted to increase economic gain and sustainable rice production. Adopting timely and effectively appropriate weed management techniques we can reduce a significant amount of yield loss and about 0.43 million ton (MT) additional yield could be increased by 2030. To achieve the target weed management should be done from the very beginning of rice production and up to 30-35 DAP (days after planting) for Aus season, 35-40 DAT (days after transplanting) for T. Aman season and 40-45 DAT for Boro season which indicates critical period of weed infestation in Aus, T. Aman and Boro season. The main approach is that rice field have to keep free from weed up to that days by 2/3 hand weeding (HW) or application of herbicide fb (Followed by) 1HW or applying weeder fb 1HW which is called integrated weed management. Herbicide should be applied at proper time and dose which reduce 61% weeding cost. Mechanical weeding (MW) reduces 50% weeding cost that keeps environment friendly. Future weed science research specially herbicide efficacy with correct time and dose, new molecule herbicide with low environmental effect, herbicide residues in soil plant system, bioherbicide, allelopathic variety, weed competetive variety, mechanical weeder with related technological developments need a multidimensional approach for ecologically sustainable integrated weed management. Such a system will work toward a socially permissible, environmentally sound, economically feasible, productive and sustainable agricultural system. Bangladesh Rice J. 24 (2): 133-159, 2021

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Weed Control, Environmental Impact, and Economics of Weed Management Strategies in Glyphosate-Resistant Soybean

Weed Technology ◽

10.1614/wt-d-10-00116.1 ◽

2011 ◽

Vol 25 (4) ◽

pp. 535-541 ◽

Cited By ~ 13

Author(s):

Christie L. Stewart ◽

Robert E. Nurse ◽

Laura L. Van Eerd ◽

Richard J. Vyn ◽

Peter H. Sikkema

Keyword(s):

Environmental Impact ◽

Weed Control ◽

Weed Management ◽

Management Strategies ◽

Cost Effective ◽

Weed Species ◽

Visible Injury ◽

The One ◽

Gross Margins ◽

Herbicide Programs

With the number of glyphosate-resistant weed species increasing in North America and a lack of new herbicide chemistries being developed, growers are shifting toward using older herbicides that are more expensive and may be less environmentally friendly. Therefore, to determine which weed management strategies are most cost effective and have the lowest impact on the environment we evaluated the efficacy, environmental impact, and the profitability of several weed management strategies in glyphosate-resistant soybean over a 3-yr period (2007 to 2009) at three locations in southwestern Ontario, Canada. No visible injury to soybean was observed with the herbicide treatments evaluated. A sequential application of glyphosate consistently provided high levels of weed control (99 to 100%) at 56 d after treatment in comparison with one- or two-pass herbicide programs. Soybean yield did not differ between the two-pass herbicide programs and glyphosate applied early POST; however, a yield benefit was found with a sequential application of glyphosate or a PRE herbicide followed by glyphosate compared with glyphosate applied only at late POST. The two-pass herbicide programs had higher environmental impact (EI) (> 23) than the one-pass herbicide programs (< 15), except when imazethapyr was followed by or tank-mixed with glyphosate, which had an equivalent EI (∼ 14) to the one-pass herbicide programs. Not surprisingly because of the low purchase price of glyphosate, gross margins were highest for treatments that included glyphosate. However, to reduce the selection pressure on glyphosate-resistant weed biotypes, to reduce environmental impact, and to increase gross margins a combination of glyphosate with another mode of action would be most beneficial. In this study glyphosate + imazethapyr was the best alternative to a sequential two-pass glyphosate program.

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Growth and Phenology of Vulpia Myuros in Comparison with Apera Spica-Venti, Alopecurus Myosuroides and Lolium Multiflorum in Monoculture and in Winter Wheat

Plants ◽

10.3390/plants9111495 ◽

2020 ◽

Vol 9 (11) ◽

pp. 1495

Author(s):

Muhammad Javaid Akhter ◽

Bo Melander ◽

Solvejg Kopp Mathiassen ◽

Rodrigo Labouriau ◽

Svend Vendelbo Nielsen ◽

...

Keyword(s):

Winter Wheat ◽

Weed Management ◽

Lolium Multiflorum ◽

Management Strategies ◽

Integrated Weed Management ◽

Growth Stages ◽

Neighborhood Design ◽

Alopecurus Myosuroides ◽

Winter Cereals ◽

Arable Weed

Vulpia myuros has become an increasing weed problem in winter cereals in Northern Europe. However, the information about V. myuros and its behavior as an arable weed is limited. Field and greenhouse experiments were conducted in 2017/18 and 2018/19, at the Department of Agroecology in Flakkebjerg, Denmark to investigate the emergence, phenological development and growth characteristics of V. myuros in monoculture and in mixture with winter wheat, in comparison to Apera spica-venti, Alopecurus myosuroides and Lolium multiflorum. V. myuros emerged earlier than A. myosuroides and A. spica-venti but later than L. multiflorum. Significant differences in phenological development were recorded among the species. Overall phenology of V. myuros was more similar to that of L. multiflorum than to A. myosuroides and A. spica-venti. V. myuros started seed shedding earlier than A. spica-venti and L. multiflorum but later than A. myosuroides. V. myuros was more sensitive to winter wheat competition in terms of biomass production and fecundity than the other species. Using a target-neighborhood design, responses of V. myuros and A. spica-venti to the increasing density of winter wheat were quantified. At early growth stages “BBCH 26–29”, V. myuros was suppressed less than A. spica-venti by winter wheat, while opposite responses were seen at later growth stages “BBCH 39–47” and “BBCH 81–90”. No significant differences in fecundity characteristics were observed between the two species in response to increasing winter wheat density. The information on the behavior of V. myuros gathered by the current study can support the development of effective integrated weed management strategies for V. myuros.

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An evaluation of a shoulder rehabilitation class in a UK hospital following evidence-based modifications

Physiotherapy Practice and Research ◽

10.3233/ppr-200408 ◽

2021 ◽

pp. 1-8

Author(s):

Emily Kell ◽

John A. Hammond ◽

Sophie Andrews ◽

Christina Germeni ◽

Helen Hingston ◽

...

Keyword(s):

Patient Satisfaction ◽

Shoulder Pain ◽

Management Strategies ◽

Cost Effective ◽

Rehabilitation Programme ◽

Patient Specific ◽

Satisfaction Survey ◽

Evidence Based ◽

Patient Satisfaction Survey ◽

Significant Difference

OBJECTIVES: Shoulder pain is a common musculoskeletal disorder, which carries a high cost to healthcare systems. Exercise is a common conservative management strategy for a range of shoulder conditions and can reduce shoulder pain and improve function. Exercise classes that integrate education and self-management strategies have been shown to be cost-effective, offer psycho-social benefits and promote self-efficacy. This study aimed to examine the effectiveness of an 8-week educational and exercise-based shoulder rehabilitation programme following the introduction of evidence-based modifications. METHODS: A retrospective evaluation of a shoulder rehabilitation programme at X Trust was conducted, comparing existing anonymised Shoulder Pain and Disability Index (SPADI) and Patient-Specific Functional Scale (PSFS) scores from two cohorts of class participants from 2017-18 and 2018-19 that were previously collected by the physiotherapy team. Data from the two cohorts were analysed separately, and in comparison, to assess class efficacy. Descriptive data were also analysed from a patient satisfaction survey from the 2018-19 cohort. RESULTS: A total of 47 patients completed the 8-week shoulder rehabilitation programme during the period of data collection (2018-2019). The 2018-19 cohort showed significant improvements in SPADI (p 0.001) and PSFS scores (p 0.001). No significant difference was found between the improvements seen in the 2017-18 cohort and the 2018-19 cohort. 96% of the 31 respondents who completed the patient satisfaction survey felt the class helped to achieve their goals. CONCLUSION: A group-based shoulder rehabilitation class, which included loaded exercises and patient education, led to improvements in pain, disability and function for patients with rotator cuff related shoulder pain (RCRSP) in this outpatient setting, but anticipated additional benefits based on evidence were not observed.

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Cyanobacterial Abundance and Microcystin Profiles in Two Southern British Lakes: The Importance of Abiotic and Biotic Interactions

Toxins ◽

10.3390/toxins12080503 ◽

2020 ◽

Vol 12 (8) ◽

pp. 503 ◽

Cited By ~ 1

Author(s):

David M. Hartnell ◽

Ian J. Chapman ◽

Nick G. H. Taylor ◽

Genoveva F. Esteban ◽

Andrew D. Turner ◽

...

Keyword(s):

Water Management ◽

Linear Regression Analysis ◽

Management Strategies ◽

Biotic Interactions ◽

Cost Effective ◽

Multiple Linear Regression Analysis ◽

Tandem Mass ◽

Recreational Waters ◽

Cyanobacteria Blooms ◽

Freshwater Bodies

Freshwater cyanobacteria blooms represent a risk to ecological and human health through induction of anoxia and release of potent toxins; both conditions require water management to mitigate risks. Many cyanobacteria taxa may produce microcystins, a group of toxic cyclic heptapeptides. Understanding the relationships between the abiotic drivers of microcystins and their occurrence would assist in the implementation of targeted, cost-effective solutions to maintain safe drinking and recreational waters. Cyanobacteria and microcystins were measured by flow cytometry and liquid chromatography coupled to tandem mass spectrometry in two interconnected reservoirs varying in age and management regimes, in southern Britain over a 12-month period. Microcystins were detected in both reservoirs, with significantly higher concentrations in the southern lake (maximum concentration >7 µg L−1). Elevated microcystin concentrations were not positively correlated with numbers of cyanobacterial cells, but multiple linear regression analysis suggested temperature and dissolved oxygen explained a significant amount of the variability in microcystin across both reservoirs. The presence of a managed fishery in one lake was associated with decreased microcystin levels, suggestive of top down control on cyanobacterial populations. This study supports the need to develop inclusive, multifactor holistic water management strategies to control cyanobacterial risks in freshwater bodies.

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Self-fill oxygen technology: benefits for patients, healthcare providers and the environment

Breathe ◽

10.1183/20734735.013515 ◽

2016 ◽

Vol 12 (2) ◽

pp. 113-119 ◽

Cited By ~ 2

Author(s):

Phyllis Murphie ◽

Nick Hex ◽

Jo Setters ◽

Stuart Little

Keyword(s):

Positive Impact ◽

Healthcare Providers ◽

Cost Savings ◽

Cost Effective ◽

Evidence Base ◽

Environmental Benefits ◽

List Type ◽

Potential Cost ◽

Unlimited Supply ◽

Technology Benefits

“Non-delivery” home oxygen technologies that allow self-filling of ambulatory oxygen cylinders are emerging. They can offer a relatively unlimited supply of ambulatory oxygen in suitably assessed people who require long-term oxygen therapy (LTOT), providing they can use these systems safely and effectively. This allows users to be self-sufficient and facilitates longer periods of time away from home. The evolution and evidence base of this technology is reported with the experience of a national service review in Scotland (UK). Given that domiciliary oxygen services represent a significant cost to healthcare providers globally, these systems offer potential cost savings, are appealing to remote and rural regions due to the avoidance of cylinder delivery and have additional lower environmental impact due to reduced fossil fuel consumption and subsequently reduced carbon emissions. Evidence is emerging that self-fill/non-delivery oxygen systems can meet the ambulatory oxygen needs of many patients using LTOT and can have a positive impact on quality of life, increase time spent away from home and offer significant financial savings to healthcare providers.Educational aimsProvide update for oxygen prescribers on options for home oxygen provision.Provide update on the evidence base for available self-fill oxygen technologies.Provide and update for healthcare commissioners on the potential cost-effective and environmental benefits of increased utilisation of self-fill oxygen systems.

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Comparative Study of the Effect of Different Weed Management Strategies on Disease Severity and Marketable Yield of Paprika (Capsicum Annuum L.) in the Smallholder Farming Sector of Zimbabwe

Journal of Plant Protection Research ◽

10.2478/v10045-008-0011-z ◽

2008 ◽

Vol 48 (1) ◽

pp. 107-117 ◽

Cited By ~ 1

Author(s):

Maxwell Handiseni ◽

Julia Sibiya ◽

Vincent Ogunlela ◽

Irene Koomen

Keyword(s):

Comparative Study ◽

Capsicum Annuum ◽

Weed Management ◽

Leaf Spot ◽

Management Strategies ◽

Smallholder Farming ◽

Marketable Yield ◽

Weed Density ◽

Marketable Fruit ◽

Hand Weeding

Comparative Study of the Effect of Different Weed Management Strategies on Disease Severity and Marketable Yield of Paprika (Capsicum AnnuumL.) in the Smallholder Farming Sector of ZimbabweOn-farm trials were conducted in the Chinyika Resettlement Area of Zimbabwe under dryland conditions to investigate the effects of different weed management methods on disease incidence, severity and paprika (Capsicum annuum) pod yield. The weed control treatments included hand weeding at 2 and 6 weeks after transplanting (WAT); ridge re-moulding at 3,6 and 9 WAT; application 4l/ha Lasso (alachlor) immediately after transplanting, and Ronstar (oxidiazinon) at 2l/ha tank mixed with Lasso at 2l/ha one day before transplanting. The herbicide-water solution was applied at the rate of 200l/ha using a knapsack sprayer. Major diseases identified were bacterial leaf spot (Xanthomonas campestrispv.vesicatoria), cercospora leaf spot (Cercospora unamunoi), grey leaf spot (Stemphylium solani) and powdery mildew (Leveillula taurica) in both seasons. For the 2000/2001 season hand weeding at 2 and 6 WAT and ridge re-moulding at 3, 6 and 9 WAT had the greatest reduction effect on the area under disease progress curve (AUDPC) and the highest marketable fruit yield. In the 2001/2002 season, both herbicide treatments had the same effect as hand weeding and ridge re-moulding on AUDPC and marketable fruit yield. The least weed density was obtained by ridge re-moulding at 3, 6, and 9 WAT in the 2000/2001 season. Weed density was statistically the same across all treatments except the check treatment in 2001/2002 season. Hand weeding operations were significantly (p < 0.05) effective and consequently gave the highest added profits mainly because of their effect on major weeds such asDatura stramonium.

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Cucumber vs Ants: a Case Against the Myth of the Uses of Plant Extracts in Insect Pest Management

Sociobiology ◽

10.13102/sociobiology.v68i2.5813 ◽

2021 ◽

Vol 68 (2) ◽

pp. 5813

Author(s):

Matan Shelomi ◽

Bo-Jun Qiu ◽

Lin-Ting Huang

Keyword(s):

Plant Extracts ◽

Scientific Evidence ◽

Insect Pest ◽

Management Strategies ◽

Cost Effective ◽

Detectable Effect ◽

Realistic Situation ◽

Potential Impact ◽

High Concentrations ◽

Ant Repellent

An accumulation of questionable scientific reports on the use of natural plant extracts to control household pest insects, using biologically irrelevant experimental designs and extremely high concentrations, has resulted in a publication bias: “promising” studies claiming readily available plants can repel various insects, including social insects, despite no usable data to judge cost-effectiveness or sustainability in a realistic situation. The Internet provides a further torrent of untested claims, generating a background noise of misinformation. An example is the belief that cucumbers are “natural” ant repellent, widely reported in such informal literature, despite no direct evidence for or against this claim. We tested this popular assertion using peel extracts of cucumber and the related bitter melon as olfactory and gustatory repellents against ants. Extracts of both fruit peels in water, methanol, or hexane were statistically significant but effectively weak gustatory repellents. Aqueous cucumber peel extract has a significant but mild olfactory repellent effect: about half of the ants were repelled relative to none in a control. While the myth may have a grain of truth to it, as cucumber does have a mild but detectable effect on ants in an artificial setup, its potential impact on keeping ants out of a treated perimeter would be extremely short-lived and not cost-effective. Superior ant management strategies are currently available. The promotion of “natural” products must be rooted in scientific evidence of a successful and cost-effective implementation prospect.

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