Weed seedbank diversity and sustainability indicators for simple and more diverse cropping systems

Liebman, Matt; Nguyen, Huong; Woods, M.; Hunt, Natalie; Hill, Jason

doi:10.1111/wre.12466

Cited by 14 publications

(20 citation statements)

References 57 publications

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“…The absence of changes in population growth for most species resulted in similar weed richness among herbicide programmes for the entire duration of the experiment. This could be beneficial because a more diverse weed seedbank supports greater agroecosystem sustainability (Liebman et al, 2021;Storkey and Neve, 2018), especially if most of the weed community is comprised of species that do not represent an important threat to crop productivity.…”

Section: Weed Species Richness and Community Structurementioning

confidence: 99%

Population growth rates of weed species in response to herbicide programme intensity and their impact on weed community

et al. 2021

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The adoption of dicamba-tolerant crops has reduced the challenge of controlling glyphosate-resistant Amaranthus palmeri in these crops. However, introducing herbicide programmes with new mechanisms of action and different intensities can favour major shifts in weed communities. This can affect not only the functionality of the agroecosystem, but also resource availability to the most problematic species. The objectives of this work were to evaluate how herbicide programme structure and intensity affect (a) weed diversity, (b) population growth rate (λ) of weed species and (c) weed community structure based on λ dynamics in a dicamba-tolerant cotton monoculture. To achieve these objectives, a cotton field experiment was established to compare four herbicide programmes from 2011 to 2018. The herbicide programmes differed in the first 4 years (i.e. glyphosate every year, alternating glyphosate and glyphosate plus dicamba every other year, glyphosate plus dicamba every year, and residual herbicide and glyphosate plus dicamba every year). During the last 4 years, all programmes received glyphosate plus dicamba. The weed seedbank was evaluated every spring and λ calculated. Environmental variation from year to year was more important in determining weed richness than herbicide programmes, which exhibited similar richness across all treatments during the eight years of the study. Regardless of herbicide programme, most species maintained λ between zero and one. Only a few species were the exception with λ values above one, such as A. palmeri, Mollugo verticillata and Eleusine indica. Although glyphosate plus dicamba reduced λ for several species, this herbicide mix was less effective in reducing λ for other weeds compared with glyphosate alone, suggesting a potential antagonism that could change weed community composition. The limited changes in λ for most species suggest the capacity of weeds to adjust reproduction and survival to overcome changes in mortality rates caused by increases in herbicide use intensity.

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Section: Weed Species Richness and Community Structurementioning

confidence: 99%

Population growth rates of weed species in response to herbicide programme intensity and their impact on weed community

et al. 2021

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“…All soil types present at the site are Mollisols (Chen et al, 2014). A detailed description of the experiment site and crop management can be found in Liebman et al (2021) and the field layout and experiment design are provided in Nguyen and Liebman (accepted). Briefly, a randomized complete block, split-plot design with four replications was used to study three different crop rotation systems (2-, 3-, or 4-year; the crop sequence in each rotation was presented in Table 1 of Nguyen and Liebman, accepted).…”

Section: Methodsmentioning

confidence: 99%

“…Increased reliance on glyphosate-based weed management has caused weed floras to shift to dominance by hard-to-control species (Owen, 2008), but it is unclear whether reduction in herbicide use would cause the same problem. Liebman et al (2021) provided empirical evidence to support the hypothesis that seedbank diversity could be used as an indicator of cropping system sustainability (Storkey and Neve, 2018).…”

Section: Introductionmentioning

confidence: 91%

Weed Community Composition in Simple and More Diverse Cropping Systems

Nguyen

Liebman

2022

Front. Agron.

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Weed communities in three cropping systems suitable for the Midwestern USA were studied from 2017 to 2020 to examine how crop diversification and the intensity of herbicide use affected weed community diversity, stand density, and aboveground mass. A baseline 2-year cropping system with corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) grown in alternate years was diversified with cool-season crops, namely oat (Avena sativa L.), red clover (Trifolium pratense L.), and alfalfa (Medicago sativa L.) in 3-and 4-year systems. Herbicide was not applied in the cool-season crops. Changing weed management regime from broadcast to banded application and interrow cultivation in corn and omitting herbicide in cool-season crops of the 3- and 4-year rotations resulted in an overall reduction of herbicide a.i mass. The reduction in the mass of herbicide active ingredients was associated with increases in weed stand density, aboveground mass, and community diversity. Increased weed abundance under herbicide mass reduction was not associated with crop yield loss. In the cool-season crops phases of the 3- and 4-year rotations, weed emergence was increased but weed growth was not, as compared with the warm-season crop environments. The dominance of aggressive weed species such as common waterhemp (Amaranthus tuberculatus (Moq ex DC) J.D. Sauer) and common lambsquarter (Chenopodium album L.) tended to be greater in corn and soybean phases of the rotations than in oat, red clover, and alfalfa.

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“…Empirical measurements of waterhemp biomass and fecundity were made in 2018 at Iowa State University's Marsden Farm in Boone County, Iowa, USA, (42 • 01'N, 93 • 47'W, 333 m above sea level). The site description and crop management practices were described by Liebman et al (2021). The experiment was initiated in 2001 on a 9-hectare field to compare the performance of three different crop rotations.…”

Section: Experiments Designmentioning

confidence: 99%

Impact of Cropping System Diversification on Vegetative and Reproductive Characteristics of Waterhemp (Amaranthus tuberculatus)

Nguyen

Liebman

2022

Front. Agron.

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Corn- and soybean-dominated cropping systems create and maintain a favorable environment for summer annual weeds whose emergence and growth phenology are similar to these annual summer crops. Cropping system diversification can be an effective approach for controlling noxious weeds without increasing reliance on chemical herbicides. Diversification may be especially important for managing waterhemp, a dioecious, summer annual weed that is becoming increasingly prevalent in the US Corn Belt due to its life history characteristics and herbicide resistance profile. Compared to corn and soybean, alfalfa and oat emerge and establish earlier and are thus more competitive with warm-season weeds like waterhemp. Knowledge of vegetative and reproductive characteristics in a range of crop environments can be valuable for planning weed management strategies. However, most of the relevant characteristics for a population dynamics model were available in corn and soybean monocultures. We examined the relationship between waterhemp's aboveground mass and fecundity under four crop species' presence within three crop rotation systems: a 2-year sequence of corn and soybean; a 3-year sequence of corn, soybean, and oat intercropped with red clover; and a 4-year sequence of corn, soybean, oat intercropped with alfalfa, and alfalfa. All the rotation systems were treated with conventional or reduced rates of herbicides. We established eighteen linear equations to predict waterhemp's fecundity from dried aboveground mass in each crop and associated crop management program since measuring the latter allows for quicker estimation of fecundity compared to counting seeds on each individual plant. Rotation system and crop phase within rotation system had significant effects on all the response variables but weed control regime on some. The sex ratios at maturity were slightly female-biased in oat and alfalfa. Mature waterhemp plants were larger in corn and soybean than in oat and alfalfa. Oat and alfalfa were planted earlier than corn and soybean and successfully competed for resources against waterhemp despite the absence of herbicide or interrow cultivation. Frequent hay cuts in alfalfa served as physical weed control and contributed to suppressing waterhemp and other weeds substantially.

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Weed seedbank diversity and sustainability indicators for simple and more diverse cropping systems

Abstract: This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Cited by 14 publications

References 57 publications

Population growth rates of weed species in response to herbicide programme intensity and their impact on weed community

Population growth rates of weed species in response to herbicide programme intensity and their impact on weed community

Weed Community Composition in Simple and More Diverse Cropping Systems

Impact of Cropping System Diversification on Vegetative and Reproductive Characteristics of Waterhemp (Amaranthus tuberculatus)

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