The Critical Period for Weed Control: Revisiting Data Analysis

Knežević, Stevan Z.; Datta, Avishek

doi:10.1614/ws-d-14-00035.1

Cited by 66 publications

(82 citation statements)

References 23 publications

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“…Las menores densidades se registraron en los tratamientos LC 10 y LC 20 , los cuales se mantuvieron libres de competencia los primeros 10 y 20 días del cultivo. En la Tabla 6, se muestra la prueba de Tukey (α=0,05) para la producción de raíces de zanahoria, donde las relaciones de los datos reportados muestran como la producción total fue favorecida cuando los tratamientos estuvieron libres de competencia desde el inicio del cultivo (Knezevic et al, 2015).…”

Section: Resultados Y Discusiónunclassified

Período crítico de competencia de la Zanahoria (Daucus carota L.) y malezas asociadas al cultivo

Dotor

Mendoza

Morillo

2018

rcia

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RESUMENLas malezas constituyen uno de los problemas fitosanitarios que afectan la rentabilidad de los cultivos. El periodo crítico de competencia con el cultivo (PCC), permite prever el nivel de interferencia de las malezas sobre la producción del cultivo de interés. El objetivo de esta investigación fue determinar el PCC entre zanahoria y las plantas asociadas al cultivo, en el municipio de Ventaquemada, departamento de Boyacá, implementando un diseño en Bloques Completos al Azar, con 12 tratamientos y cuatro repeticiones, el cual incluía un grupo de tratamientos libres de malezas por un periodo de tiempo (10, 20, 30, 40 ó 50 días), al término del cual se permitía el crecimiento de las mismas en el cultivo, de modo que el cultivo estuviese primero libre y luego en competencia (LC) y en el segundo grupo de tratamientos se permitía primero el desarrollo del proceso de competencia entre la maleza y el cultivo por un intervalo de tiempo igual al del grupo anterior y luego se retiraban las malezas. El mayor número de plantas cosechadas se obtuvo en la parcela libre de competencia durante los primeros 50 días después de emergencia. El mayor rendimiento se obtuvo en el tratamiento que se mantuvo limpio

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Section: Resultados Y Discusiónunclassified

Período crítico de competencia de la Zanahoria (Daucus carota L.) y malezas asociadas al cultivo

Dotor

Mendoza

Morillo

2018

rcia

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“…Although the sigmoid model is not recommended for additive design, it is one of the most commonly used and appropriate models in other weed research topics. Sigmoid curves are extensively utilised for predicting weed emergence (Werle et al ., ,b), herbicide dose–response (Ritz et al ., ) and critical time for weed removal (Knezevic & Datta, ). For example, in herbicide dose–response studies, the parameter e is meaningful and important for comparison of herbicides doses that control 50% of a weed population (Oliveira et al ., ).…”

Section: Discussionmentioning

confidence: 99%

“…Studies of crop–weed competition show that yield loss (YL) is sensitive to differences in the period between crop and weed emergence (Knezevic et al ., ; Hock et al ., ). It brings to light the importance of the concepts of a critical period of weed control (Knezevic et al ., ; Knezevic & Datta, ) and economic thresholds (Coble & Mortensen, ; Wilkerson et al ., ). A weed threshold is described as ‘a point at which weed density causes important crop losses’ (Knezevic et al ., ).…”

Section: Introductionmentioning

confidence: 99%

Additive design: the concept and data analysis

et al. 2018

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Crop-weed competition is extensively studied in weed science. The additive design, in which weed density varies and the crop density is kept constant, is the most commonly utilised design in plant competition studies. The additive design is important to calculate economic weed thresholds and improve weed control decision-making. Crop-weed competition studies are usually conducted by weed scientists, who sometimes report misleading conclusions because of lack of statistical knowledge needed for data analysis of such studies. Therefore, the objective of this manuscript is to provide the concept of additive design and demonstrate the model selection approach for describing crop-weed density relationship to non-statisticians. We evaluated three models routinely used in the literature to interpret data from additive designs, including polynomial quadratic, sigmoid and rectangular hyperbola curves. Based on the described statistical criteria, we demonstrated the rectangular hyperbola to be the most appropriate model to describe data from an additive design study looking at Richardia brasiliensis and Commelina benghalensis competition with maize (Zea mays). Moreover, we describe step-by-step how to perform the statistical analysis in R software and interpret the results of crop-weed competition studies. We suggest the use of the rectangular hyperbola as a standardised model for crop-weed competition in additive design.

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“…The CPWC often coincides with time of ground cover in cowpea. The magnitude of acceptable yield loss solely depends on the discretion of the farmers (Knezevic & Datta, 2015). It provides farmers a decision tool necessary to manage their limited resources effectively on weed management.…”

Section: Impact Of Weed Interference Duration and Critical Time Of Wementioning

confidence: 99%

Weed Interference and Control in Cowpea Production: A Review

Osipitan¹

2017

JAS

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In spite of the great economic potential of cowpea as both domestic and commercial crop, a number of constraints, which include insect pests, diseases and weeds, limits its production in West and many parts of Africa. Weeds reduced cowpea yield and value by competing for light, water and nutrients. Cowpea suffers from weeds particularly when the crop is in the early growth stages before ground cover. Yield losses cause by weeds alone in cowpea production can be as high as 76% depending on the cowpea cultivar, environment and weed management practices. A timely weed removal at the critical period, which falls within the first 40 days of cowpea growth, would help to prevent an unacceptable yield. Weed management in cowpea has been with low technology. Hand weeding is the most widely used weed control method in cowpea but they are usually expensive and labour intensive. Cultural practices such as narrow row spacing and planting of early maturing varieties are also used for weed control in cowpea. Herbicides, which are relatively easy to use and less expensive, have not been widely adopted for weed control in cowpea. There are limited number of selective herbicides with wide spectrum for weed control in cowpea. However, an integrated practices that involved pre-emergence weed control using herbicides or physical weeding, and a supplementary weed removal that would ensure weed control up to 40 days after cowpea emergence could substantially prevent yield losses associated with weed interference.

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The Critical Period for Weed Control: Revisiting Data Analysis

Cited by 66 publications

References 23 publications

Período crítico de competencia de la Zanahoria (Daucus carota L.) y malezas asociadas al cultivo

Período crítico de competencia de la Zanahoria (Daucus carota L.) y malezas asociadas al cultivo

Additive design: the concept and data analysis

Weed Interference and Control in Cowpea Production: A Review

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