Light Quality and the Critical Period for Weed Control in Soybean

Weed Science ◽  
2012 ◽  
Vol 60 (1) ◽  
pp. 86-91 ◽  
Author(s):  
Emily Green-Tracewicz ◽  
Eric R. Page ◽  
Clarence J. Swanton
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Critical Period ◽  
Light Quality ◽  
Morphological Changes ◽  
Management Strategies ◽  
Leaf Number ◽  
Integrated Weed Management ◽  
Weed Competition ◽  
Shade Avoidance

The critical period for weed control (CPWC) is an integral component of integrated weed management strategies. Several studies have defined the CPWC in soybean under varying agronomic conditions, yet none have described the mechanisms involved in crop yield losses caused by weed competition. We hypothesized that under nonresource-limiting conditions, morphological changes resulting from the expression of shade avoidance could be used to define a period of developmental sensitivity to low red-to-far-red ratio (R : FR) that would overlap with the defined CPWC in soybean. Two experiments (a sequential harvest and a weed addition/removal series) were conducted in 2008 and 2009 under controlled environmental conditions to address this hypothesis. Two light-quality treatments were used: (1) high R : FR ratio (i.e., weed-free), and (2) low R : FR ratio (i.e., weedy). The low R : FR ratio treatment induced shade avoidance responses in soybean, which included increases in height, internode length, and the shoot : root ratio, as well as a reduction in biomass accumulation and leaf number. Using the morphological changes in biomass and leaf number observed in the weed addition/removal series, a period of developmental sensitivity to low R : FR was defined between the first trifoliate (V1) and third trifoliate (V3) stages of soybean development. This period was found to be very similar to the CPWC previously defined by field studies of soybean–weed competition.

Weed management in direct seeded rice: A review

2017 ◽  
Author(s):  
Sheeja K Raj ◽  
Elizabeth K Syriac
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Sustainable Management ◽  
Critical Period ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Integrated Weed Management ◽  
Weed Flora ◽  
Direct Seeded

Weeds are the major biological constraint in direct seeded rice (DSR) due to the concurrent emergence of competitive weeds, absence of water to suppress weeds at the time of seedling emergence and emergence of difficult to control weeds. Strategies on weed management in direct seeded rice depend on critical period of weed control, weed flora and method to be adopted. In order to achieve the long term and sustainable management of weeds in DSR an integration of different weed management strategies like integrated weed management (IWM) are essential. The literature regarding the critical period of weed control, weed flora and different methods for the sustainable management of weeds in direct seeded rice are reviewed in this paper.

scholarly journals Perspectives for using light quality knowledge as an advanced ecophysiological weed management tool

2009 ◽  
Vol 27 (2) ◽  
pp. 407-419 ◽  
Author(s):  
A. Merotto Jr. ◽  
A.J. Fischer ◽  
R.A. Vidal
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Critical Period ◽  
Light Quality ◽  
Current Knowledge ◽  
Spectral Composition ◽  
Management Tool ◽  
Light Limitation ◽  
Potential Contribution ◽  
Traditional Concept

The current knowledge of light quality effects on plant morphogenesis and development represents a new era of understanding on how plant communities perceive and adjust to available resources. The most important consequences of light quality cues, often mediated by decreasing in red far-red ratios with respect to the spectral composition of incident sunlight radiation, affecting weed-crop interaction are the increased plant height and shoot to root ratio in anticipation of competition by light quantity, water or nutrients. Although the concepts related to light quality have been extensively studied and several basic process of this phenomenon are well known, little applications of photomorphogenic signaling currently are related to agricultural problems or weed management. The objectives of this review are to describe how light quality change can be a triggering factor of interspecific interference responses, to analyze how this phenomenon can be used to predict weed interference, to reevaluate the critical periods of interference concept, and to discuss its potential contribution towards developing more weed competitive crop varieties. Knowledge on light quality responses involved in plant sensing of interspecific competition could be used to identify red/far-red threshold values, indicating when weed control should be started. Light quality alterations by weeds can affect grain crop development mainly in high yielding fields. Unlike the traditional concept or the critical period of competition, light quality mediated interference implies that the critical period for weed control could start before the effects of direct resource (water, nutrients and available light) limitation actually occur. The variability in light quality responses among crop genotypes and the identification of mutants insensitive to light quality effects indicate that this characteristic can be selected or modified to develop cultivars with enhanced interspecific interference ability. Knowledge on light quality-elicited responses represents a new possibility to understand the underlying biology of interspecific interference, and could be used in the development of new weed management technologies.

Planting date influences critical period of weed control in sweet corn

Weed Science ◽  
2006 ◽  
Vol 54 (5) ◽  
pp. 928-933 ◽  
Author(s):  
Martin M. Williams
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Critical Period ◽  
Sweet Corn ◽  
Relative Yield ◽  
Planting Date ◽  
Integrated Weed Management ◽  
Yield Losses ◽  
Yield Data ◽  
Weed Interference

The critical period for weed control (CPWC) identifies the phase of the crop growth cycle when weed interference results in unacceptable yield losses; however, the effect of planting date on CPWC is not well understood. Field studies were conducted in 2004 and 2005 at Urbana, IL, to determine CPWC in sweet corn for early May (EARLY) and late-June (LATE) planting dates. A quantitative series of treatments of both increasing duration of interference and length of weed-free period were imposed within each planting-date main plot. The beginning and end of the CPWC, based on 5% loss of marketable ear mass, was determined by fitting logistic and Gompertz equations to the relative yield data representing increasing duration of weed interference and weed-free periods, respectively. Weed interference stressed the crop more quickly and to a greater extent in EARLY, relative to LATE. At a 5% yield-loss level, duration of weed interference for 160 and 662 growing-degree days (GDD) from crop emergence marked the beginning of the CPWC for EARLY and LATE, respectively. When maintained weed-free for 320 and 134 GDD, weeds emerging later caused yield losses of less than 5% for EARLY and LATE, respectively. Weed densities exceeded 85 plants m−2for the duration of the experiments and predominant species included barnyardgrass, common lambsquarters, common purslane, redroot pigweed, and velvetleaf. Weed canopy height and total aboveground weed biomass were 300% and 500% higher, respectively, for EARLY compared with LATE. Interactions between planting date and CPWC indicate the need to consider planting date in the optimization of integrated weed management systems for sweet corn. In this study, weed management in mid-June–planted sweet corn could have been less intensive than early May–planted corn, reducing herbicide use and risk of herbicide carryover to sensitive rotation crops.

scholarly journals A REVIEW ON NON-CHEMICAL WEED MANAGEMENT IN MAIZE (ZEA MAYS L.)

2021 ◽  
Vol 1 (1) ◽  
pp. 46-51
Author(s):  
A. Duwadi ◽  
A. Acharya ◽  
S. Gautam
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Critical Period ◽  
Weed Competition ◽  
Chemical Application ◽  
Organic System ◽  
Sustainable Solutions ◽  
Weed Population ◽  
Mechanical Methods ◽  
Crop Weed Competition

Weed is omnipresent species that compete with major crops for light, nutrients, space, and water for their growth and development and ultimately deteriorate the ideal environment for crops growth. In the present context, herbicide application is the easiest and seemingly economical approach for weed control in south-Asian countries. In contrary, the side effects of herbicide on health and environment impose to adopt for the non-chemical method of weed management. This paper reviewed the menace of herbicide, crop weed association, the critical period of crop-weed competition, and different methods of organic weed control implemented especially for maize. The main objective of this review is to maneuver a weed control strategy for maize other than the chemical application. The findings of different research suggested that a critical period of crop-weed competition in maize lies between 2 to 8 weeks after crop sowing. Many mechanical methods for weed control in maize proved efficient but seemed labour intensive and biological methods provided maximum security against specific weed species. The cultural method in combination with other methods effectively reduced the weed population in the maize field. It was found that, if various components of non-chemical weed management are implemented systematically, we can control the weed population with higher economic return and achieve the goal of organic food production with sustainable solutions. Weed control in the organic system focuses on management techniques designed to prevent weed emergence, give a competitive advantage to the main crop, and act for sustainable solutions. The non-chemical integrated weed management system is recommended to reduce the use of herbicide and for sustainable production. A review of non-chemical weed management in maize could be helpful for researchers to provide useful, sustainable, and environmentally friendly solutions to farmers to solve the problem of weed infestation in the maize crop along with substantial yield improvement.

A Systems Comparison of Contrasting Organic Weed Management Strategies

Weed Science ◽  
2017 ◽  
Vol 66 (1) ◽  
pp. 109-120 ◽  
Author(s):  
Bryan Brown ◽  
Eric R. Gallandt
Keyword(s):  
Seed Production ◽  
Weed Management ◽  
Critical Period ◽  
Yield Loss ◽  
Sweet Corn ◽  
Management Strategies ◽  
Weed Competition ◽  
Weed Seed ◽  
Period System ◽  
Organic Weed Management

Weed management strategies differ in their ability to control weeds, and often have unique agroecological implications. To provide growers with an improved sense of trade-offs between weed control and ecological effects, we implemented several prominent organic weed management strategies in yellow onion in 2014 and 2015. Strategies included cultivation of weed seedlings during the early, weed-sensitive “critical period” of the crop; frequent cultivation events to ensure “zero seed rain”; and weed suppression with polyethylene or natural mulches. As expected, end-of-season weed biomass and weed seed production were greatest in the critical period system and nearly zero for the zero seed rain system. Weeds were also well controlled in natural mulch systems. Average onion yield per treatment was 50.7 Mg ha−1. In 2014, the critical period system and the polyethylene mulch systems demonstrated yield loss, likely due to weed competition and excessive soil temperature, respectively. Onion soluble solids content was also diminished in these systems in 2014, but bulb firmness was greatest in unmulched systems. Carabid beetles, earthworms, soil compaction, soil nitrate, and microbial biomass were affected by weed management strategy, with natural-mulched systems generally performing most favorably. However, these effects were not substantial enough to affect yield of a subsequent sweet corn crop grown in weed-free conditions. In contrast, sweet corn managed with only early-season cultivations demonstrated yield loss (P=0.004) in plots where the critical period treatment was implemented the prior year, indicating that weed competition resulting from abundant weed seed production in that system was the most influential legacy effect of the weed management strategies.

scholarly journals Critical Period of Weed Control in Aerobic Rice

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
M. P. Anwar ◽  
A. S. Juraimi ◽  
B. Samedani ◽  
A. Puteh ◽  
A. Man
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Critical Period ◽  
Yield Loss ◽  
Field Trials ◽  
Integrated Weed Management ◽  
Aerobic Rice ◽  
View Point ◽  
Weed Interference ◽  
Economic View

Critical period of weed control is the foundation of integrated weed management and, hence, can be considered the first step to design weed control strategy. To determine critical period of weed control of aerobic rice, field trials were conducted during 2010/2011 at Universiti Putra Malaysia. A quantitative series of treatments comprising two components, (a) increasing duration of weed interference and (b) increasing length of weed-free period, were imposed. Critical period was determined through Logistic and Gompertz equations. Critical period varied between seasons; in main season, it started earlier and lasted longer, as compared to off-season. The onset of the critical period was found relatively stable between seasons, while the end was more variable. Critical period was determined as 7–49 days after seeding in off-season and 7–53 days in main season to achieve 95% of weed-free yield, and 23–40 days in off-season and 21–43 days in main season to achieve 90% of weed-free yield. Since 5% yield loss level is not practical from economic view point, a 10% yield loss may be considered excellent from economic view point. Therefore, aerobic rice should be kept weed-free during 21–43 days for better yield and higher economic return.

Extending the critical period for weed control model to better include weed succession using common sunflower as a mimic weed in high-yielding cotton

2021 ◽  
pp. 1-27
Author(s):  
Graham W. Charles ◽  
Ian N. Taylor
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Critical Period ◽  
Yield Loss ◽  
Logistic Function ◽  
Integrated Weed Management ◽  
Traditional Practice ◽  
Crop Planting ◽  
Logistic Functions ◽  
Weed Emergence

Abstract The critical period for weed control (CPWC) adds value to integrated weed management by identifying the period during which weeds need to be controlled to avoid yield losses exceeding a defined threshold. However, the traditional application of the CPWC does not identify the timing of control needed for weeds that emerge late in the critical period. In this study, CPWC models were developed from field data in high yielding cotton crops during three summer seasons from 2005 to 2008, using the mimic weed; common sunflower, at densities of 2 to 20 plants m−2. Common sunflower plants were introduced at up to 450 growing degree days (GDD) after crop planting and removed at successive 200 GDD intervals after introduction. The CPWC models were described using extended Gompertz and logistic functions that included weed density, time of weed introduction and time of weed removal (logistic function only) in the relationships. The resulting models defined the CPWC for late emerging weeds, identifying a period after weed emergence before weed control was required to prevent yield loss exceeding the yield-loss threshold. Where weeds emerged in sufficient numbers toward the end of the critical period, the model predicted that crop yield loss resulting from competition by these weeds would not exceed the yield-loss threshold until well after the end of the CPWC. These findings support the traditional practice of ensuring weeds are controlled before crop canopy closure, with later weed control inputs used as required.

scholarly journals Weed Management in 2050: Perspectives on the Future of Weed Science

Weed Science ◽  
2018 ◽  
Vol 66 (3) ◽  
pp. 275-285 ◽  
Author(s):  
James H. Westwood ◽  
Raghavan Charudattan ◽  
Stephen O. Duke ◽  
Steven A. Fennimore ◽  
Pam Marrone ◽  
...  
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
New Technologies ◽  
Management Strategies ◽  
Integrated Weed Management ◽  
World Population ◽  
Plant Interactions ◽  
Weed Science ◽  
Modes Of Action ◽  
The Future

AbstractThe discipline of weed science is at a critical juncture. Decades of efficient chemical weed control have led to a rise in the number of herbicide-resistant weed populations, with few new herbicides with unique modes of action to counter this trend and often no economical alternatives to herbicides in large-acreage crops. At the same time, the world population is swelling, necessitating increased food production to feed an anticipated 9 billion people by the year 2050. Here, we consider these challenges along with emerging trends in technology and innovation that offer hope of providing sustainable weed management into the future. The emergence of natural product leads in discovery of new herbicides and biopesticides suggests that new modes of action can be discovered, while genetic engineering provides additional options for manipulating herbicide selectivity and creating entirely novel approaches to weed management. Advances in understanding plant pathogen interactions will contribute to developing new biological control agents, and insights into plant–plant interactions suggest that crops can be improved by manipulating their response to competition. Revolutions in computing power and automation have led to a nascent industry built on using machine vision and global positioning system information to distinguish weeds from crops and deliver precision weed control. These technologies open multiple possibilities for efficient weed management, whether through chemical or mechanical mechanisms. Information is also needed by growers to make good decisions, and will be delivered with unprecedented efficiency and specificity, potentially revolutionizing aspects of extension work. We consider that meeting the weed management needs of agriculture by 2050 and beyond is a challenge that requires commitment by funding agencies, researchers, and students to translate new technologies into durable weed management solutions. Integrating old and new weed management technologies into more diverse weed management systems based on a better understanding of weed biology and ecology can provide integrated weed management and resistance management strategies that will be more sustainable than the technologies that are now failing.

scholarly journals The Critical Period for Weed Control: Revisiting Data Analysis

Weed Science ◽  
2015 ◽  
Vol 63 (SP1) ◽  
pp. 188-202 ◽  
Author(s):  
Stevan Z. Knezevic ◽  
Avishek Datta
Keyword(s):  
United States ◽  
Data Analysis ◽  
Weed Control ◽  
Crop Yield ◽  
Weed Management ◽  
Critical Period ◽  
The United States ◽  
Growth Cycle ◽  
Integrated Weed Management ◽  
Yield Losses

There is an ever-larger need for designing an integrated weed management (IWM) program largely because of the increase in glyphosate-resistant weeds, not only in the United States but also worldwide. An IWM program involves a combination of various methods (cultural, mechanical, biological, genetic, and chemical) for effective and economical weed control (Swanton and Weise 1991). One of the first steps in designing an IWM program is to identify thecritical period for weed control(CPWC), defined as a period in the crop growth cycle during which weeds must be controlled to prevent crop yield losses (Zimdahl 1988).

Weed Management in Pulses: A Review

2020 ◽  
Author(s):  
Sheeja K. Raj ◽  
J. K. Sinchana
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Abiotic Stresses ◽  
Critical Period ◽  
Management Practices ◽  
Yield Loss ◽  
Threshold Level ◽  
Weed Competition ◽  
Initial Growth ◽  
Biotic And Abiotic Stresses

Pulses are the important crop after cereals and is the cheapest source of dietary protein. After the Green revolution, the production of pulses in India remain stagnant over the years due to various biotic and abiotic stresses. Among the various biotic stresses, weeds are the major one which causes severe yield loss in pulses. Due to initial slow growth of pulses, weeds emerge first and gain competitive advantage over the crop and exhibit smothering effect on crop. Moreover, major area of pulses (84 per cent) are under rainfed condition and grown in combination with non-legume crop. As a result, pulses are subjected to various types of biotic and abiotic stresses. Weeds besides causing direct loss in yield also hinder farm activities and serve as alternate host to many pests. Weed management in pulses is essential to bring the weeds below the threshold level to maximize the seed yield and quality. The literature regarding the importance of weed management in pulses, weed flora, critical period of crop weed competition and different weed management methods of weed control are collected and presented in this paper.Weeds are the predominant biological constraint in pulse production due to the slow initial growth of the crop. Strategies’ of weed management depends on the weed competition, types of weeds present and weed control method adopted. In general, critical period of weed competition for short duration pulses is up to 30 days and for long duration pulse crops it is up to 60 days. The major three types of weeds viz., grasses, broad leaved weeds and sedges were found in association with pulses. Intensity of weed infestation varies with agroecological conditions and crop management practices followed. A system approach is necessary to maintain the weed population below the economic threshold level thereby reducing the yield loss. Integrated weed management (IWM) which has been proved to be more effective than any single method in alleviating the buildup of weeds in pulse crop.

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