Simulation Models on the Ecology and Management of Arable Weeds: Structure, Quantitative Insights, and Applications

In weed science and management, models are important and can be used to better understand what has occurred in management scenarios, to predict what will happen and to evaluate the outcomes of control methods. To-date, perspectives on and the understanding of weed models have been disjointed, especially in terms of how they have been applied to advance weed science and management. This paper presents a general overview of the nature and application of a full range of simulation models on the ecology, biology, and management of arable weeds, and how they have been used to provide insights and directions for decision making when long-term weed population trajectories are impractical to be determined using field experimentation. While research on weed biology and ecology has gained momentum over the past four decades, especially for species with high risk for herbicide resistance evolution, knowledge gaps still exist for several life cycle parameters for many agriculturally important weed species. More research efforts should be invested in filling these knowledge gaps, which will lead to better models and ultimately better inform weed management decision making.

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Risk-Efficiency Criteria for Evaluating Economics of Herbicide-Based Weed Management Systems in Corn

Weed Technology ◽

10.1614/wt-03-152r2 ◽

2004 ◽

Vol 18 (3) ◽

pp. 687-697 ◽

Cited By ~ 4

Author(s):

Thomas R. Hoverstad ◽

Jeffrey L. Gunsolus ◽

Gregg A. Johnson ◽

Robert P. King

Keyword(s):

Decision Making ◽

Weed Control ◽

Stochastic Dominance ◽

Weed Management ◽

Crop Production ◽

Management Systems ◽

Management Decision ◽

Pass System ◽

Application Systems ◽

Mean Variance

Evaluation of economic outcome associated with a given weed management system is an important component in the decision-making process within crop production systems. The objective of this research was to investigate how risk-efficiency criteria could be used to improve herbicide-based weed management decision making, assuming different risk preferences among growers. Data were obtained from existing weed management trials in corn conducted at the University of Minnesota Southern Research and Outreach Center at Waseca. Weed control treatments represented a range of practices including one-pass soil-applied, one-pass postemergence, and sequential combinations of soil and postemergence herbicide application systems. Analysis of risk efficiency across 23 herbicide-based weed control treatments was determined with the mean variance and stochastic dominance techniques. We show how these techniques can result in different outcomes for the decision maker, depending on risk attitudes. For example, mean variance and stochastic dominance techniques are used to evaluate risk associated with one- vs. two-pass herbicide treatments with and without cultivation. Based on these analyses, it appears that a one-pass system is preferred by a risk-averse grower. However, we argue that this may not be the best option considering potential changes in weed emergence patterns, application timing concerns, etc. The techniques for economic analysis of weed control data outlined in this article will help growers match herbicide-based weed management systems to their own production philosophies based on economic risk.

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Estimations and projections of Avena fatua dynamics under multiple management scenarios in crop fields using simplified longitudinal monitoring

PLoS ONE ◽

10.1371/journal.pone.0245217 ◽

2021 ◽

Vol 16 (1) ◽

pp. e0245217

Author(s):

Saeko Matsuhashi ◽

Motoaki Asai ◽

Keita Fukasawa

Keyword(s):

Weed Management ◽

Avena Fatua ◽

Integrated Weed Management ◽

Weed Species ◽

Management Scenarios ◽

Management Options ◽

Remarkable Effect ◽

Crop Fields ◽

Wheat Cultivation ◽

Agricultural Weed

Integrated weed management (IWM) is currently the most appropriate and effective method of agricultural weed control. To determine the most effective strategy, it is necessary to compare the effects of different control options and their rotation. Avena fatua (common wild oat) is one of the most common and economically threatening grass weed species of cereal crops worldwide. To examine the effects of non-chemical weed management options (farmland use, delayed sowing, and summer irrigation) on control of A. fatua, we recorded coverage levels and field conditions in 41 sites during the spring growing season of winter wheat for about 10 years. A transition matrix model was then constructed to project coverage levels of A. fatua under each management option using ordinal logistic regression. The results showed that farmland use had a remarkable effect on coverage; notably, planting of paddy rice and vegetables, which respectively eliminated the effect of coverage in the previous year and facilitated rapid convergence of coverage to 0%. Thus, although 90% of fields under continuous wheat cultivation were found to be at risk of A. fatua colonization, the risk was reduced to almost 0% with rotation of effective farmland use. As summer irrigation was also effective, more than 50% of wheat fields with the option continuously converged to no risk for A. fatua colonization. When the different management cycles were repeated, the effects were observed within 3 years, with a steady state reached in less than 10 years. Overall, these results suggest that simplified monitoring data could help decision-making on IWM, thereby helping to improve the efficiency of agricultural production.

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Studies on Weed Diversity and Phytosociology in Wheat Crop

Journal of AgriSearch ◽

10.21921/jas.v7i03.18695 ◽

2020 ◽

Vol 7 (03) ◽

Author(s):

SANJEEV KUMAR ◽

SHIVANI JAN

Keyword(s):

Weed Management ◽

Winter Season ◽

Cropping System ◽

Management Decision ◽

Wheat Crop ◽

Weed Species ◽

Large Area ◽

Importance Value Index ◽

Importance Value ◽

Phalaris Minor

Rice-wheat is the dominant cropping system in Patna district where wheat is generally grown in winter season and a large area is sown by using seed drill machines. The present investigation is based on the study of biodiversity of weeds under zero tilled condition in Patna district of Bihar. The weed inventory surveys and phytosociological studies in wheat fields were conducted during 2016-19 to identify the weed flora composition, density, frequency and Importance value index of 30 major weed species in wheat. In the study, Asteraceae was found as the largest family in respect of weed species whereas Poaceae and Leguminosaefamilystood at the second position in terms of weed species. Phytosociological studies further revealed that Phalaris minor (6.48) and Cynodon dactylon (5.03) have larger relative frequency among other weed species while Chenopodiumalbum(5.18)and Avena fatua(4.44)have larger relative abundance in the study area. Studies on relative density of weeds revealed that densities of Phalaris minor (7.06) and Chenopodium album (5.65) were higher over other weed species and similar trends were also observed in respect of Importance value index of weeds. Therefore, while planning effective weed management strategy, these two weeds (P. minor and C. album) must be focused. The study will provide an appraisal of species through quantitative characters and will allow effective weed management decision.

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Integrating Insect, Resistance, and Floral Resource Management in Weed Control Decision-Making

Weed Science ◽

10.1614/ws-d-16-00052.1 ◽

2016 ◽

Vol 64 (4) ◽

pp. 743-756 ◽

Cited By ~ 9

Author(s):

Antonio DiTommaso ◽

Kristine M. Averill ◽

Michael P. Hoffmann ◽

Jeffrey R. Fuchsberg ◽

John E. Losey

Keyword(s):

Decision Making ◽

Weed Management ◽

Crop Production ◽

European Corn Borer ◽

Crop Yields ◽

Optimal Decision ◽

Management Decision ◽

Egg Mass ◽

Transgenic Crop ◽

Corn Borer

Managing agricultural pests with an incomplete understanding of the impacts that tactics have on crops, pests, and other organisms poses risks for loss of short-term profits and longer-term negative impacts, such as evolved resistance and nontarget effects. This is especially relevant for the management of weeds that are viewed almost exclusively as major impediments to crop production. Seldom considered in weed management are the benefits weeds provide in agroecosystems, which should be considered for optimal decision-making. Integration of weed costs and benefits will become increasingly important as management for pests transitions away from nearly complete reliance on herbicides and transgenic crop traits as the predominant approach for control. Here, we introduce a weed-management decision framework that accounts for weed benefits and exemplify how in-crop weed occurrence can increase crop yields in which a highly damaging insect also occurs. We highlight a case study showing how management decision-making for common milkweed, which is currently controlled primarily with glyphosate in herbicide-tolerant corn, can be improved by integrating management of the European corn borer (ECB), which is currently controlled primarily by the transgenic toxin Cry1 inBacillus thuringiensiscorn. Our data reveal that milkweed plants harboring aphids provide a food source (honeydew) for parasitoid wasps, which attack ECB eggs. Especially at high ECB population densities (> 1 egg mass leaf–1), maintaining low milkweed densities (< 1 stem m–2), effectively helps to minimize yield losses from ECB and to increase the economic injury level of this aggressive perennial weed. In addition, milkweed is the host for the monarch butterfly, so breeding-ground occurrences of the plant, including crop fields, may help sustain populations of this iconic insect. Using a more-holistic approach to integrate the management of multiple crop pests has the capacity to improve decision-making at the field scale, which can improve outcomes at the landscape scale.

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Implications of weed seedbank dynamics to weed management

Weed Science ◽

10.1017/s0043174500092948 ◽

1997 ◽

Vol 45 (3) ◽

pp. 329-336 ◽

Cited By ~ 161

Author(s):

Douglas D. Buhler ◽

Robert G. Hartzler ◽

Frank Forcella

Keyword(s):

Weed Control ◽

Weed Management ◽

Plant Ecology ◽

Management Systems ◽

Integrated Weed Management ◽

Management Decision ◽

Plant Responses ◽

Weed Seed ◽

Weed Species ◽

Tillage Practices

The species composition and density of weed seed in the soil vary greatly and are closely linked to the cropping history of the land. Altering tillage practices changes weed seed depth in the soil, which plays a role in weed species shifts and affects efficacy of control practices. Crop rotation and weed control practices also affect the weed seedbank. Information on the influence of cropping practices on the weed seedbank should be a useful tool for integrated weed management. Decision aid models use information on the weed seedbank to estimate weed populations, crop yield loss, and recommend weed control tactics. Understanding the light requirements of weed seed may provide new approaches to weed management. Improving and applying our understanding of weed seedbank dynamics is essential to developing improved weed management systems. The principles of plant ecology must be integrated with the science of weed management to develop strategies that take advantage of basic plant responses in weed management systems for agronomic crops.

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WeedSOFT®: a weed management decision support system

Weed Science ◽

10.1614/p2002-154 ◽

2004 ◽

Vol 52 (1) ◽

pp. 115-122 ◽

Cited By ~ 39

Author(s):

Christophe Neeser ◽

J. Anita Dille ◽

Gopal Krishnan ◽

David A. Mortensen ◽

Jeffery T. Rawlinson ◽

...

Keyword(s):

Decision Support ◽

Decision Support System ◽

Support System ◽

Weed Management ◽

Management Strategies ◽

Maximum Yield ◽

Management Decision ◽

Weed Species ◽

Line Drawings ◽

Selection Of

WeedSOFT® is a decision support system that was developed to help farmers and consultants in Nebraska with the selection of optimal weed management strategies. WeedSOFT® evolved from HERB, a bioeconomic model for soybean that was developed in North Carolina. The program is composed of four independent modules, namely, ADVISOR, EnviroFX, MapVIEW, and WeedVIEW. ADVISOR helps the user select a treatment based on maximum yield or maximum net gain. EnviroFX and MapVIEW provide environmentally relevant herbicide information and county soil maps that indicate vulnerability to groundwater contamination. WeedVIEW is a visual library of color images and line drawings of 46 common weed species. Over 500 farmers and consultants in Nebraska and adjacent states use WeedSOFT®. As a result of the current regionalization effort, the user base is expected to increase rapidly during the next 2 or 3 yr. This article explains the algorithms implemented in the current version of WeedSOFT®.

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Influence of Early-Season Yield Loss Predictions from WeedSOFT®and Soybean Row Spacing on Weed Seed Production from a Mixed-Weed Community

Weed Technology ◽

10.1614/wt-03-150r1 ◽

2004 ◽

Vol 18 (2) ◽

pp. 412-418 ◽

Cited By ~ 6

Author(s):

Andrew A. Schmidt ◽

William G. Johnson

Keyword(s):

Seed Production ◽

Crop Yield ◽

Weed Management ◽

Yield Potential ◽

Management Decision ◽

Yield Reduction ◽

Weed Seed ◽

Weed Species ◽

Early Season ◽

Giant Foxtail

Seed production from weeds that are missed by herbicide application can affect future weed populations and management decisions. It may be possible to expand the utility of computerized weed management decision aids to include an estimate of weed seed production resulting from selected treatments based on crop yield potential. Field studies were conducted in soybean near Columbia, MO, to determine whether weed control recommendations based on crop yield potential from a computerized weed management decision aid influence weed seed production in two soybean row spacings. At approximately 28 d after planting, weed densities and heights were entered into WeedSOFT®to generate a list of treatments ranked by predicted crop yields. Treatments included: (1) highest predicted crop yield in a glyphosate-resistant system, (2) highest predicted crop yield in a nonglyphosate-resistant system, (3) a 10% yield reduction, (4) a 20% yield reduction, and (5) an untreated control. These treatments were applied to soybean grown in 38- and 76-cm rows. Treatments that provided 90% or higher control of an individual species at 22 d after treatment usually produced less seed than untreated checks. Weed seed production based on early-season herbicide efficacy showed a linear relationship and was relatively predictable (r2≥ 0.52) for the predominant weed species. For less dominant weed species, weed seed production was not strongly correlated (r2≤ 0.27) to early-season herbicide efficacy but apparently influenced by control of other weed species. Narrow row spacing reduced giant foxtail biomass both years but did not reduce common ragweed and ivyleaf morningglory biomass. Narrow rows did not decrease giant foxtail, common ragweed, and ivyleaf morningglory seed production.

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Centralization and Effectiveness of Reward Management in Multinational Enterprises

Journal of Personnel Psychology ◽

10.1027/1866-5888/a000195 ◽

2018 ◽

Vol 17 (2) ◽

pp. 55-65 ◽

Cited By ~ 1

Author(s):

Michael Tekieli ◽

Marion Festing ◽

Xavier Baeten

Keyword(s):

Decision Making ◽

Social Identity Theory ◽

Multinational Enterprises ◽

Role Identity ◽

Management Decision ◽

Role Identities ◽

Management Decision Making ◽

New Perspective ◽

Subsidiary Managers ◽

The Relationship

Abstract. Based on responses from 158 reward managers located at the headquarters or subsidiaries of multinational enterprises, the present study examines the relationship between the centralization of reward management decision making and its perceived effectiveness in multinational enterprises. Our results show that headquarters managers perceive a centralized approach as being more effective, while for subsidiary managers this relationship is moderated by the manager’s role identity. Referring to social identity theory, the present study enriches the standardization versus localization debate through a new perspective focusing on psychological processes, thereby indicating the importance of in-group favoritism in headquarters and the influence of subsidiary managers’ role identities on reward management decision making.

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