scholarly journals Defining Integrated Weed Management: A Novel Conceptual Framework for Models

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 747
Author(s):  
Jonathan Storkey ◽  
Joseph Helps ◽  
Richard Hull ◽  
Alice E. Milne ◽  
Helen Metcalfe
Keyword(s):  
Population Dynamics ◽  
Conceptual Framework ◽  
Herbicide Resistance ◽  
Weed Management ◽  
Integrated Weed Management ◽  
Management Options ◽  
Weed Population ◽  
Weed Population Dynamics ◽  
Population Dynamics Models ◽  
Dynamics Models

Weed population dynamics models are an important tool for predicting the outcome of alternative Integrated Weed Management (IWM) scenarios. The growing problem of herbicide resistance has increased the urgency for these tools in the design of sustainable IWM solutions. We developed a conceptual framework for defining IWM as a standardised input template to allow output from different models to be compared and to design IWM scenarios. The framework could also be used as a quantitative metric to determine whether more diverse systems are more sustainable and less vulnerable to herbicide resistance using empirical data. Using the logic of object-oriented programming, we defined four classes of weed management options based on the stage in the weed life cycle that they impact and processes that mediate their effects. Objects in the same class share a common set of properties that determine their behaviour in weed population dynamics models. Any weed control “event” in a system is associated with an object, meaning alternative management scenarios can be built by systematically adding events to a model either to compare existing systems or design novel approaches. Our framework is designed to be generic, allowing IWM systems from different cropping systems and countries to be compared.

Weed Demography and Population Dynamics: Implications for Threshold Management

1992 ◽  
Vol 6 (1) ◽  
pp. 184-190 ◽  
Author(s):  
Nicholas Jordan
Keyword(s):  
Population Dynamics ◽  
Seed Dispersal ◽  
Weed Management ◽  
Threshold Value ◽  
Soil Factors ◽  
Factors Affecting ◽  
Weed Population Dynamics ◽  
Population Dynamics Models ◽  
Dynamics Models ◽  
Optimum Threshold

Threshold weed management methods have recently been elaborated to consider effects of threshold management on weed population dynamics. Such economic optimum thresholds are calculated using population-dynamics models which require detailed information about weed demography, including seed production (as affected by events between germination and seed dispersal), seed dispersal, and seed survival and movement in soil. Factors affecting any of these aspects of demography appear likely to modulate the growth rate of a sub-threshold population and therefore to influence the economic optimum threshold value. To test this conjecture and evaluate weed threshold management, including associated risk, improved understanding is particularly needed of weed seed dispersal, seedbank processes, and unpredictable demographic variation.

Noxious Weed Population Dynamics Education Model

1997 ◽  
Vol 11 (1) ◽  
pp. 182-188 ◽  
Author(s):  
Bruce D. Maxwell ◽  
Roger L. Sheley
Keyword(s):  
Population Dynamics ◽  
Weed Management ◽  
Educational Software ◽  
Management Options ◽  
Community Interactions ◽  
Weed Population ◽  
Weed Population Dynamics ◽  
Demographic Processes ◽  
Noxious Weed ◽  
Population Demographic

An educational software program was developed to demonstrate the interactions among weed population demographic processes, plant community interactions, and grassland noxious weed management options. The software includes an example model parameterized to simulate yellow starthistle population dynamics and graphic output. The software allows students to change weed and competing grass population demographic parameters, herbicide, and biological control management options. The graphic output allows the user to observe the outcome of integration of weed biology and various weed management options.

scholarly journals The R Package PROSPER: An Environment for Modeling Weed Population Dynamics and the Evolution of Herbicide Resistance

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 958
Author(s):  
Christoph von Redwitz ◽  
Friederike de Mol
Keyword(s):  
Population Dynamics ◽  
Herbicide Resistance ◽  
R Package ◽  
Model Parameters ◽  
Weed Species ◽  
Management Options ◽  
Phenotypic Resistance ◽  
Weed Population ◽  
Weed Population Dynamics ◽  
The Impact

Weed management is a challenge for farmers worldwide, and the problem is exacerbated by the spread of weed herbicide resistance. Simulation models that combine population dynamics and genetics are valuable tools for predicting the impact of competing management options on weed density, allele frequency, and phenotypic resistance levels. The new R package PROSPER provides functions for the forward simulation of weed population dynamics on a field scale, the selection of individuals according to their sensitivity to herbicides, and the recombination of alleles during reproduction. Objects are provided to enter and save model parameters in a clear structure, and to save output data for further processing in R. The basic functions are extensible with R code. PROSPER combines individual-based population dynamics with monogenic or polygenic diploid inheritance and flexible selection pressure. Stochasticity can be included at all model steps. Two examples of the population dynamics of two annual weed species with herbicide resistance are presented. All parameters and the models are available in PROSPER. In addition to simulation, PROSPER is intended for sharing and publishing population dynamic parameters and models, which is easily done thanks to R.

Weed seed return as influenced by the critical weed-free period in corn (Zea mays L.)

1999 ◽  
Vol 79 (1) ◽  
pp. 165-167 ◽  
Author(s):  
Clarence J. Swanton ◽  
Kevin Chandler ◽  
Anil Shrestha
Keyword(s):  
Weed Management ◽  
Zea Mays L ◽  
Soil Surface ◽  
Management Systems ◽  
Integrated Weed Management ◽  
Critical Periods ◽  
Weed Seed ◽  
Weed Population ◽  
Weed Population Dynamics ◽  
Total Seed

Seed return from later emerging weeds is a concern in weed management systems based on critical periods of control. A study in Ontario found that estimated weed seed return to the soil surface was influenced by the duration of weed control in corn and the prevailing environmental conditions. Weeds emerging after the 8- to 11-leaf stage of corn growth did not cause an increase in total seed number compared to the residual seed bank in the weed-free control. Key words: Seedbank, weed population dynamics, integrated weed management

scholarly journals Simulation of crop-weed competition : Models and their applications

2005 ◽  
Vol 77 (1) ◽  
pp. 3-11 ◽  
Author(s):  
S.E. Weaver
Keyword(s):  
Weed Management ◽  
Systems Approach ◽  
Management Strategies ◽  
Simulation Models ◽  
Weed Competition ◽  
Weed Population Dynamics ◽  
Resource Levels ◽  
Population Dynamics Models ◽  
Crop Weed Competition ◽  
Dynamics Models

Competition between crops and weeds is a complex phenomenon. Comprehensive, process-oriented simulation models which treat competition in a mechanistic rather than an empirical fashion, can offer insight into relationships among competition, crop and weed density, relative time of emergence, various morphological and physiological traits, and resource levels. They can also be used for prediction as part of a Systems approach to weed management. This paper reviews the features of a number of recent simulation models of crop-weed competition, the species for which they have been parameterized, and their applications. To date, these models have been used primarily to predict crop yield losses due to weed competition. Their ability to simulate weed seed production in response to the environment has not been exploited. The next step is to link simulation models of crop-weed competition to weed population dynamics models, in order to improve our ability to predict the effect of various weed management strategies over time. Advantages and drawbacks of a modeling approach to weed management problems are discussed.

scholarly journals Upgrading the RIM Model for Improved Support of Integrated Weed Management Extension Efforts in Cropping Systems

2014 ◽  
Vol 28 (4) ◽  
pp. 703-720 ◽  
Author(s):  
Myrtille Lacoste ◽  
Stephen Powles
Keyword(s):  
Herbicide Resistance ◽  
Weed Management ◽  
Cropping Systems ◽  
Integrated Management ◽  
Integrated Weed Management ◽  
Weed Species ◽  
Management Options ◽  
Rigid Ryegrass ◽  
And Control

RIM, or “Ryegrass Integrated Management,” is a user-friendly weed management software that integrates long-term economics. As a model-based decision support system, RIM enables users to easily build 10-year cropping scenarios and evaluate the impacts of management choices on annual rigid ryegrass populations and long-term profitability. Best used in a workshop format to enable learning through interactions, RIM can provide insights for the sustainable management of ryegrass through “what-if” scenarios in regions facing herbicide resistance issues. The upgrade of RIM is presented, with changes justified from an end-user perspective. The implementation of the model in a new, intuitive software format is presented, as well as the revision, update, and documentation of over 40 management options. Enterprises, establishment systems, and control options were redefined to represent current practices, with the notable inclusion of customizable herbicide options and techniques for weed seed control at harvest. Several examples of how RIM can be used with farmers to demonstrate the benefits of adopting recommended practices for managing or delaying the onset of herbicide resistance are presented. Originally designed for the dryland broadacre systems of the Australian southern grainbelt, RIM's underlying modeling was restructured to facilitate future updates and adaptation to other weed species and cropping regions.

Nonlinear Population Dynamics: Models, Experiments and Data

1998 ◽  
Vol 194 (1) ◽  
pp. 1-9 ◽  
Author(s):  
J.M. Cushing ◽  
R.F. Costantino ◽  
Brian Dennis ◽  
R.A. Desharnais ◽  
Shandelle M. Henson
Keyword(s):  
Population Dynamics ◽  
Population Dynamics Models ◽  
Dynamics Models

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 Challenging population dynamics models with new data: how accurate were our inferences?

2020 ◽  
Vol 27 (1) ◽  
pp. 008-016
Author(s):  
Verónica C. Andreo ◽  
Mauricio Lima ◽  
Jaime J. Polop ◽  
M. Cecilia Provensal
Keyword(s):  
Population Dynamics ◽  
Population Dynamics Models ◽  
Dynamics Models
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