The Role of Weed Seed Contamination in Grain Commodities as Propagule Pressure

Abstract The international grain trade is a major pathway for the introduction of alien plants because grain commodities can be contaminated with various weed seeds. To evaluate how alien weed seeds derived from imported grain commodities affect local vegetation in international trading ports, we conducted a vegetation survey on a set of grain landing ports and non-grain landing ports in nine regions throughout Japan to compare the vegetation between these two types of ports. We also surveyed weed seed contamination of wheat imported into Japan, and the contamination rate was calculated for each species based on our survey and previous studies on weed seed contamination. The vegetation clearly differed between the grain landing ports and the non-grain ports. In the grain landing ports, alien species were more abundant than in non-grain landing ports. All indicator species of the grain landing ports were reported to be contaminants in grain commodities. Furthermore, there was a tendency for the more abundant species at the grain landing ports to show higher contamination rates in grain commodities. These results indicate that contaminant seeds spill from imported grain in grain landing ports, and highly contaminated species are likely to become established. We clearly show that weed seed contamination in grain commodities plays an important role in propagule pressure. Gathering information about the prevalence of weeds in grain-exporting countries and monitoring the weed species composition in imported grain commodities is becoming increasingly important for predicting the unintentional introduction of troublesome weeds and identifying effective weed management options.

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Effects of Initial Seed-Bank Density on Weed Seedling Emergence during the Transition to an Organic Feed-Grain Crop Rotation

Weed Science ◽

10.1614/ws-09-031.1 ◽

2009 ◽

Vol 57 (5) ◽

pp. 533-540 ◽

Cited By ~ 10

Author(s):

Richard G. Smith ◽

Randa Jabbour ◽

Andrew G. Hulting ◽

Mary E. Barbercheck ◽

David A. Mortensen

Keyword(s):

Seed Bank ◽

Weed Management ◽

Cover Crop ◽

Management Practices ◽

Transition Period ◽

Red Clover ◽

Weed Seed ◽

Weed Species ◽

Organic Certification ◽

Weed Seeds

The transition period to certified organic production can present a significant weed management challenge for growers. Organic certification requires that prohibited fertilizers and pesticides must not have been used for 36 mo before harvest of the first organic crop. Understanding how organic management practices and initial weed seed-bank densities affect weed population dynamics during the transition period may improve weed management efficacy and adoption of organic practices. We examined how tillage systems (full or reduced) and cover crop species planted during the first transition year (rye or a mixture of timothy and red clover) affect the seedling densities of three common annual weed species, common lambsquarters, velvetleaf, and foxtail spp., during the 3-yr transition period. Weed seeds were applied in a one-time pulse at the beginning of the study at three densities, low, medium, and high (60, 460, and 2,100 seeds m−2, respectively), and cumulative seedling densities of each species were assessed annually. Treatment factors had variable and species-specific effects on weed seedling densities. In general, the full-tillage system, with an initial cover crop of timothy and red clover, resulted in the lowest density of weed seedlings following seed-bank augmentation. There was little consistent association between the initial densities of applied weed seeds in the weed seed bank at the start of the transition and weed seedling densities at the end of the transition period. This suggests that when multiple crop and weed cultural management practices are employed during the organic transition period, initial failures in weed management may not necessarily lead to persistent and intractable annual weed species management problems following organic certification.

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The nature and consequence of weed spread in cropping systems

Weed Science ◽

10.1017/s004317450009295x ◽

1997 ◽

Vol 45 (3) ◽

pp. 337-342 ◽

Cited By ~ 42

Author(s):

Donald C. Thill ◽

Carol A. Mallory-Smith

Keyword(s):

Herbicide Resistance ◽

Weed Management ◽

Short Distance ◽

Crop Production ◽

Cropping Systems ◽

Weed Seed ◽

Management Options ◽

Crop Species ◽

Weed Seeds ◽

Pollen Movement

Weeds spread through movement of seeds and vegetative reproductive propagules. Pollen movement can spread weedy traits, such as herbicide resistance, between related weed and crop species. Weed seeds can spread short or long distances by natural plant dehiscence mechanisms, wind, water, animals, and man&s activities. This symposium paper is a practical review of short-distance spread of weed seeds in and between nearby arable fields and noncrop lands, examining some of the causes of spread and subsequent effects on crop production. Pollen movement, as it affects the spread of herbicide resistance, also is considered a component of short-distance weed spread. Specific weed management options can be used to reduce man-caused weed seed spread within and between nearby fields, thus reducing potential crop yield losses. Long-term management will be more difficult for weed seed spread by natural dispersal mechanisms.

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A Review of the Soil Seedbank from a Weed Scientists Perspective

Agronomy ◽

10.3390/agronomy9070369 ◽

2019 ◽

Vol 9 (7) ◽

pp. 369 ◽

Cited By ~ 9

Author(s):

Lauren M. Schwartz-Lazaro ◽

Josh T. Copes

Keyword(s):

Weed Management ◽

Weed Species ◽

Short Term ◽

Management Options ◽

Herbicide Resistant ◽

The Past ◽

Weed Seeds ◽

Soil Seedbank ◽

Management Tactics

Despite efforts to eliminate weeds, they continue to thrive. Weed persistence is reliant upon the soil seedbank. Knowledge of the soil seedbank is continually expanding, but with the rising threat of herbicide-resistant weeds in agriculture, weed scientists have, in the past, focused their management tactics to more short-term solutions that tackle the aboveground problems, rather than long-term solutions. This article summarized the soil seedbank dynamics of weed seeds and derives management options, from a North American weed scientists’ perspective, that (i) favor the depletion of the seedbank, (ii) favor the germination of the seedbank, and (iii) reduce the possibilities of seed produced by the seedlings that germinated to return the soil. These options can potentially deter herbicide resistance and are successful in the short term for reducing field weed infestations, but are likely to take many years to affect recruitment to the weed seedbank, including recruitment of weed species with a high risk for resistance. The natural longevity of the seedbank suggests that alternative or additional weed management tactics are required to reduce the store of weed seeds in the active seedbank.

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Weed Seed Bank Dynamics: Weed Seed Bank Modulation Through Tillage and Weed Management

Planta Daninha ◽

10.1590/s0100-83582018360100083 ◽

2018 ◽

Vol 36 (0) ◽

Author(s):

Q. MAQSOOD ◽

R.N. ABBAS ◽

A. KHALIQ ◽

Z.A. ZAHIR

Keyword(s):

Seed Bank ◽

Weed Management ◽

Management Practices ◽

Movement Pattern ◽

Soil Core ◽

Seed Density ◽

Weed Seed ◽

Weed Species ◽

Seed Bank Dynamics ◽

Weed Seeds

ABSTRACT: A field trial was conducted with the aim of assessing weed seed bank status of soil under maize cultivation. It was worked out by sampling from soil corer at different depths ranging from 0-5, 5-10, 10-15, 15-20 and 20-25 cm. Weed seed bank was monitored with a cultivator, a rotavator, a mouldboard plough (MB) and a chisel plough in tilled plots under Atrazine 330 EC at 1.00 kg a.i. ha-1 at 20 DAS, hand weeding at 20 and 40 DAS and no weeding. Sixteen weed species were identified in soil samples, four species contributing about 72% of the total weed seed bank. Tillage system was more important determinant of weed seed density than the weed management practices. Movement pattern of weed seeds by all tillage treatments differ significantly over three weeding management practices at 0-5 cm soil core. Horse purslane (28%) and jungle rice (20%) were with high relative abundance. In both years, change in weed seed bank in upper 0-5 cm soil was significant as seeds germinating from this layer were either removed by hand or killed with chemical or left unchecked. Only chisel plough tapped the soil core below 20 cm and caused a small reduction in weed seed density. Mouldbold plough effectively buried weed seeds below 10 cm but not beyond 20 cm and hand hoeing reduced weed seed bank by killing weeds at seedling stage.

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Influence of crop rotation, tillage, and management inputs on weed seed production

Weed Science ◽

10.1017/s0043174500091591 ◽

1999 ◽

Vol 47 (2) ◽

pp. 175-183 ◽

Cited By ~ 44

Author(s):

George O. Kegode ◽

Frank Forcella ◽

Sharon Clay

Keyword(s):

Seed Production ◽

Crop Rotation ◽

Crop Production ◽

Conservation Tillage ◽

Farming Systems ◽

Crop Rotations ◽

Weed Seed ◽

Weed Species ◽

Weed Seeds ◽

Ridge Tillage

Approaches to crop production that successfully reduce weed seed production can benefit farming systems by reducing management inputs and costs. A 5-yr rotation study was conducted in order to determine the effects that interactions between crop rotation, tillage, and amount of herbicide and fertilizer (management inputs) have on annual grass and broad-leaved weed seed production and fecundity. There were 10 crop rotation and tillage system combinations and three levels of management inputs (high, medium, and low). Green and yellow foxtail were the major weed species, and together they yielded between 76 and 93% of collected weed seeds. From 1990 to 1994, average grass weed seed productions were 7.3 by 103, 3.7 by 1036.1 by 103and 5.7 by 103seeds m−-2, whereas average broad-leaved weed seed productions were 0.4 by 103, 0.4 by 103, 1.4 by 103, and 0.4 by 103seeds m−-2in crop rotations using conventional tillage (moldboard plow), conservation tillage, no tillage, and ridge tillage, respectively. Crop rotations using conventional or ridge tillage consistently produced more grass and broad-leaved weed seeds, especially in low-input plots. There was little difference in weed seed production among input levels for crop rotations using conservation tillage. Comparing rotations that began and ended with a corn crop revealed that by increasing crop diversity within a rotation while simultaneously reducing the amount of tillage, significantly fewer grass and broad-leaved weed seeds were produced. Among the rotations, grass and broad-leaved weed fecundity were highly variable, but fecundity declined from 1990 to 1994 within each rotation, with a concomitant increase in grass and broad-leaved weed density over the same period. Crop rotation in combination with reduced tillage is an effective way of limiting grass and broad-leaved weed seed production, regardless of the level of management input applied.

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Relation between Soil Weed Seedbank and Weed Management Practises and Diversity in Farms in Kisii Central Sub County, Nyanza

Journal of Horticulture and Plant Research ◽

10.18052/www.scipress.com/jhpr.10.1 ◽

2020 ◽

Vol 10 ◽

pp. 1-14

Author(s):

Charles N. Nyamwamu ◽

Rebecca Karanja ◽

Peter Mwangi

Keyword(s):

Seed Bank ◽

Weed Management ◽

Management Practices ◽

Soil Seed Bank ◽

Shannon Index ◽

Weed Seed ◽

Weed Species ◽

Western Kenya ◽

Weed Diversity ◽

Hand Weeding

This study sought to determine the relation between soil weed seed bank and weed management practices and diversity in farms in Kisii Central Sub County, Western Kenya. Eight administrative sub-locations were randomly selected. Ten farms were selected at equal distance along transect laid across each sub-location. Weed soil seed bank was assessed from soil samples collected from each of the farms; a sub-sample was taken from a composite sample of ten soil cores of 5cm diameter and 15cm deep and placed in germination trays in a greenhouse. Weed diversity in soil weed seedbank was calculated using the Shannon index (H’). Twelve weed species from 12 genera of nine families were recorded. Diversity of the weed species in soil weed seed bank was (H'=1.48). Weed management practises significantly affected weed species soil weed seedbank reserves. Use of inefficient and ineffective hand-weeding techniques resulted in high weed species diversity and abundance.

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Poecilus lucublandus (Coleoptera: Carabidae) and Pterostichus mutus Do Not Feed on Hair Fescue, Red Sorrel, and Poverty Oatgrass Seeds

Journal of Insect Science ◽

10.1093/jisesa/iez027 ◽

2019 ◽

Vol 19 (2) ◽

Author(s):

Alexandre M M C Loureiro ◽

G Christopher Cutler ◽

Vilis O Nams ◽

Scott N White

Keyword(s):

Seed Predation ◽

Choice Test ◽

Weed Seed ◽

Weed Species ◽

Vaccinium Angustifolium ◽

Lowbush Blueberry ◽

Rumex Acetosella ◽

Weed Seeds ◽

Poecilus Lucublandus ◽

Danthonia Spicata

Abstract Poecilus lucublandus (Say), Pterostichus mutus (Say), and Harpalus rufipes (De Geer) are abundant Carabidae in lowbush blueberry fields and may contribute to weed seed predation. We used laboratory no-choice test experiments to determine if these beetles feed on seeds of hair fescue (Festuca filiformis Pourr., Poales: Poaceae), poverty oatgrass (Danthonia spicata L.), and red sorrel (Rumex acetosella L., Caryophyllales: Polygonaceae), which are common weeds in lowbush blueberry (Vaccinium angustifolium Ait., Ericales: Ericaceae) fields. Poecilus lucublandus and P. mutus did not feed on seeds of the test weed species, but H. rufipes consumed on average over 30 seeds of each species. There are other weed seeds in blueberry fields that could be palatable to P. lucublandus and P. mutus, which warrants further research on the granivory potential of these important carabid species.

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Smoke-Isolated Trimethylbutenolide Inhibits Seed Germination of Different Weed Species by Reducing Amylase Activity

Weed Science ◽

10.1614/ws-d-14-00068.1 ◽

2015 ◽

Vol 63 (1) ◽

pp. 312-320 ◽

Cited By ~ 6

Author(s):

Heino B. Papenfus ◽

Manoj G. Kulkarni ◽

Martin Pošta ◽

Jeffrey F. Finnie ◽

Johannes Van Staden

Keyword(s):

Seed Germination ◽

Weed Management ◽

Amylase Activity ◽

Management Strategies ◽

Biologically Active ◽

Weed Species ◽

Water Control ◽

Weed Seeds ◽

Dark Conditions ◽

Smoke Water

Weeds pose a great problem to farmers worldwide, and controlling weeds demands a high input cost for herbicides and labor. Because of current environmental regulations, a limited number of herbicides are commercially available (with limited modes of action) to control weeds. Smoke water and the biologically active compounds isolated from smoke affect seed germination in a significant way. Smoke water (SW) and karrikinolide (KAR1, the germination stimulant isolated from smoke) have been tested extensively for their ability to promote seed germination in a vast array of plant species. In addition to KAR1, a germination inhibitor, trimethylbutenolide (TMB), was also isolated from plant-derived smoke. The effects of SW, KAR1, and TMB were tested on five major weed species of South Africa: fleabane, hairy wild lettuce, bugweed, spilanthes, and fameflower. Seeds of these weed species were subjected to 16/8 h light/dark conditions or to constant dark conditions at constant temperatures of 20, 25, 30 C and alternating 30/20 C. SW and KAR1significantly increased germination, whereas TMB significantly inhibited germination of these weed species. Furthermore, TMB treatment reduced the amylase activity of the tested weed seeds compared with the water control. These results indicate the possibility of manipulating germination of certain weed seeds by SW, KAR1, and TMB. Thus, smoke and smoke-isolated compounds could potentially be used in new weed management strategies.

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Selecting Cost-Minimizing Herbicide Programs for Corn (Zea mays)

Weed Technology ◽

10.1017/s0890037x00040045 ◽

1996 ◽

Vol 10 (2) ◽

pp. 327-336 ◽

Cited By ~ 1

Author(s):

J. Rolf Olsen ◽

Jayson K. Harper ◽

William S. Curran

Keyword(s):

Weed Control ◽

Weed Management ◽

Conventional Tillage ◽

Programming Approach ◽

Weed Species ◽

Management Options ◽

Corn Production ◽

No Till ◽

The Cost ◽

Herbicide Programs

A computer model which selects least cost herbicide programs given a minimum desired level of weed control could provide growers with economical weed management options. Using an integer programming approach, a herbicide selection model was developed for corn production under Pennsylvania conditions. Models for three rotations (corn-soybean, corn-corn, and corn-alfalfa) under three tillage systems (conventional tillage, reduced tillage, and no-till) that evaluated 21 soil-applied and 13 postemergence herbicide options for 24 weeds were developed. Each model minimizes the cost of a herbicide program subject to a desired level of weed control. By selecting the weed species to be controlled and the level of control desired, customized herbicide programs can be generated. The models can also be used to evaluate the cost of changing the level of control desired for an individual weed species or set of weeds.

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Evaluation of New Harvesting Methods to Reduce Weeds on Arable Fields and Collect a New Feedstock

Energies ◽

10.3390/en12091688 ◽

2019 ◽

Vol 12 (9) ◽

pp. 1688 ◽

Cited By ~ 7

Author(s):

Christoph Glasner ◽

Christopher Vieregge ◽

Josef Robert ◽

Johanna Fenselau ◽

Zahra Bitarafan ◽

...

Keyword(s):

Weed Management ◽

Growing Season ◽

Integrated Weed Management ◽

Management Approach ◽

Weed Seed ◽

Galium Aparine ◽

Bromus Hordeaceus ◽

Weed Seeds ◽

Arable Fields ◽

Combine Harvester

During harvesting, grain, straw, and chaff with weed seeds are separated. The chaff is returned to the fields, resulting in weed problems in the subsequent crops. We estimated the fraction of weed seeds a combine harvester could potentially harvest and used various methods to collect the chaff and treat it with heat to kill weed seeds or reduce weed seed germination. Chaff with weed seeds was placed on top of the straw and afterwards baled with the straw as a method to remove weed seeds from the field. We exposed chaff with weed seeds to exhaust gas with various temperatures and durations to study whether this heating method could be used to reduce the input of viable weed seeds to the soil during harvesting. By collecting the shed weed seeds during the growing season, we estimated that a combine harvester could potentially harvest 41%, 11%, and 100% of the seeds produced in the growing season by Bromus hordeaceus, Cirsium arvense, and Galium aparine, respectively. When the chaff was placed on top of the straw, 45% of the weed seeds stayed in the chaff fraction on top of the straw swath after one day, 35% got into the straw swath, and 20% past through the swath to the ground. Therefore, baling straw with chaff placed on the top only had a limited effect on reducing weed seed infestation. The study showed that thermal weed seed control during harvesting could potentially be applicable and incorporated in an integrated weed management approach.

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