Ecological Implications of Using Thresholds for Weed Management

Norris, Robert S.

doi:10.1300/j144v02n01_03

Cited by 65 publications

(64 citation statements)

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“…The principles of threshold-based weed management indicate that low levels of weed competition often do not cause serious crop yield losses and may not merit the implementation of active weed control strategies [26]. Although the concerns that sub-threshold weed populations may contribute to the long-term weed seed bank are duly noted [3], there is a growing body of data suggesting that primary seed dormancy and secondary metabolites in seed as seed bank persistence mechanisms may be greatly curtailed in sub-threshold weed populations maturing under resource-limiting conditions. As such, precocious germination, which can be easily managed with broad-spectrum herbicides or mechanical means, or rapid seed death is likely to occur in seed bank additions from sub-threshold stress grown weeds.…”

Section: Discussionmentioning

confidence: 99%

“…Although sub-threshold weed communities may not be economically competitive with crops, they are still likely to produce seed, which may contribute to the long-term soil weed seed bank. Such contributions to the soil weed bank may be a major problem with threshold-based weed management, potentially leading to the proliferation of weed communities in the longer term [3].…”

Section: Introductionmentioning

confidence: 99%

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Implications of Environmental Stress during Seed Development on Reproductive and Seed Bank Persistence Traits in Wild Oat (Avena fatua L.)

et al. 2013

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Weeds produce seed under a wide range of conditions, depending on timing of emergence, prevailing crop, soil microsites, and climatic conditions, among other factors. We hypothesized that the maturation environment during weed seed development will influence reproductive allocation and seed persistence traits, such as seed dormancy and vigor, and needs to be considered when formulating weed management strategies. This research evaluated the effects of shade and drought stress on reproductive allocation, seed dormancy and seed vigor in select lines of wild oat (Avena fatua L.). Plants were grown in the greenhouse under drought stress and shade. Harvested seed were subjected to controlled after-ripening and aging regimes. Drought and shade reduced reproductive allocation and resulted in seed with less intense primary dormancy compared to the plants grown under resource-rich conditions, but had no apparent effect on seed vigor. Our data provide additional support to the hypothesis that seed dormancy within a species is a highly plastic trait that can be strongly influenced by the growth conditions of the mother plant. Such plasticity may have important implications for establishing ecologically-based weed control criteria on which threshold-based weed management systems are implemented. OPEN ACCESSAgronomy 2013, 3 538

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Implications of Environmental Stress during Seed Development on Reproductive and Seed Bank Persistence Traits in Wild Oat (Avena fatua L.)

et al. 2013

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“…Interest in the application of thresholds to the management of weeds in agricultural systems developed as an extension of their use in managing arthropod pests in crops (Norris 1999). Fundamental differences in the biology of pest animals and weeds, in particular the existence of seed banks in the latter, meant that major differences in population dynamics had to be taken into account if thresholds were to be at all useful.…”

Section: Thresholds and Management For Biodiversity Valuesmentioning

confidence: 99%

Managing for biodiversity: impact and action thresholds for invasive plants in natural ecosystems

Panetta¹,

Gooden²

2017

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Some studies examining the impacts of invasive plant species in native plant communities have demonstrated non-linear damage functions, whereby community components, such as species richness, are seemingly unaffected by the presence of an invader until it has attained relatively high levels of abundance, whereupon there is a marked decrease with further increases in abundance. Given chronic limitations in the resources available for managing invasive species, it has been argued that the most damaging invaders would be controlled most efficiently by maintaining their abundances below such threshold levels. Because many impact studies do not involve sampling over a wide range of invader abundances it is not possible to estimate the prevalence of threshold relationships. Furthermore, studies that have employed appropriate sampling methods have shown that different life forms exhibit different threshold responses, indicating that maintenance management for biodiversity values should be designed to protect the most sensitive species or groups of species. Since control costs increase with invader abundance, economic and ecological considerations are aligned when invaders are sustainably maintained at relatively low abundances. Adopting such an approach should also minimise negative impacts where damage functions are linear.

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“…O NDE depende de variáveis biológicas, como o rendimento de grãos da cultura, a perda percentual de rendimento da cultura por unidade de planta daninha e a eficiência do herbicida; e de variá-veis econômicas, como o custo de controle das infestantes e o preço do produto colhido (Lindquist & Kropff, 1996). Os NDEs, como apoio à decisão de manejo de infestantes, têm sido pouco empregados na herbologia, em razão da imprevisibilidade das variáveis biológicas (Norris, 1999) e econômicas (Kalsing & Vidal, 2010).…”

Section: Introductionunclassified

Rendimento de grãos de feijão e nível de dano econômico sob dois períodos de competição com Euphorbia heterophylla

et al. 2015

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RESUMO -O objetivo deste estudo foi avaliar o impacto da interferência deEuphorbia heterophylla (EPHHL) em diferentes densidades e épocas de semeadura sobre o rendimento do feijoeiro e seus componentes e o nível de dano econômico (NDE). O experimento foi conduzido em campo em delineamento de blocos ao acaso, em parcelas subdivididas, com quatro repetições. Nas parcelas principais foram alocadas oito densidades de EPHHL (0, 6, 10, 17, 29, 49, 83 e 142 pl m -2 ) e, nas subparcelas, duas épocas de semeadura da infestante (12 dias antes da semeadura do feijoeiro e simultaneamente à cultura). As perdas de rendimento da cultura do feijão foram diretamente proporcionais à densidade de plantas de EPHHL. A implantação simultânea das espécies cultivada e daninha resultou em perda máxima de 48% no rendimento de grãos de feijão, enquanto a semeadura de EPHHL 12 dias antes do feijoeiro resultou em perda de 60% no rendimento de grãos. O número de legumes por planta foi o principal componente do rendimento afetado pela competição. Cada planta de EPHHL reduziu em 2,4 e 5,5% o rendimento de grãos de feijoeiro, para as situações de implantação simultânea e 12 dias antes da semeadura da cultura, respectivamente. Análise de sensibilidade indicou que os valores de NDE dependeram da época de implantação da planta daninha, da expectativa de rendimento da cultura, da eficiência do herbicida, do valor do produto colhido e do custo do controle. Entretanto, em todas as simulações, o NDE foi muito baixo (<3,3 plantas m -2 ), enfatizando a necessidade de herbicidas residuais para evitar perdas econômicas na cultura.Palavras-chave: competição, Phaseolus vulgaris, perda de rendimento, nível crítico de dano, hipérbole retangular. (0, 6, 10, 17, 29, 49, 83 and 142 pl m -2 ) were allocated; and on the subplots, there were two sowings of weeds (12 days ABSTRACT -This study aimed to assess the impact of Euphorbia heterophylla (EPHHL) interference at different densities and sowing dates on common bean grain yield and its components, and to determine crop weed economic threshold (WET). The field experiment consisted of a randomized block design in a split plot arrangement of the treatments, with four replicates. On the main plots, eight densities of EPHHL

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Ecological Implications of Using Thresholds for Weed Management

Cited by 65 publications

References 0 publications

Implications of Environmental Stress during Seed Development on Reproductive and Seed Bank Persistence Traits in Wild Oat (Avena fatua L.)

Implications of Environmental Stress during Seed Development on Reproductive and Seed Bank Persistence Traits in Wild Oat (Avena fatua L.)

Managing for biodiversity: impact and action thresholds for invasive plants in natural ecosystems

Rendimento de grãos de feijão e nível de dano econômico sob dois períodos de competição com Euphorbia heterophylla

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