scholarly journals Weeds occurrence and importance under distinct intercropping systems

2011 ◽  
Vol 29 (4) ◽  
pp. 811-819
Author(s):  
G Concenço ◽  
G Ceccon ◽  
F Schwerz ◽  
I.C Fonseca ◽  
L.F Leite
Keyword(s):  
Seed Bank ◽  
Yield Loss ◽  
Soil Seed Bank ◽  
Weed Species ◽  
Short Term ◽  
Control Practice ◽  
Weed Communities ◽  
Weed Infestation

Intercropping systems involving corn are often subjected to stress caused by weeds, which usually result in 30-70 per cent yield loss when no control practice is applied. This study aimed to assess the composition of weed communities due to soil coverage, at neighboring areas submitted to distinct soil managements. The soil was collected at field and the study was conducted under a greenhouse in three steps: (1) weeds composition and importance within each treatment; (2) comparison between treatments (distinct crop and intercropping managements); (3) infestation in the area as a whole. The weed composition in the short term is influenced by the management of the area, but this shift requires some more years to be reflected at the soil seed bank. Some weed species occur in high densities and even this way they may not be the most serious weed species present in a given field. Just a few species are adapted to a given system of management in a level enough to be a troublesome weed. Areas differed in relation to weed infestation as a function of management adopted and number of years the new management was applied.

SIMULATION OF INTEGRATED CONTROL STRATEGIES FOR OROBANCHE SPP. BASED ON A LIFE CYCLE MODEL

2001 ◽  
Vol 37 (1) ◽  
pp. 37-51 ◽  
Author(s):  
E. KEBREAB ◽  
A. J. MURDOCH
Keyword(s):  
Seed Bank ◽  
Control Strategies ◽  
Soil Seed Bank ◽  
Integrated Control ◽  
Integrated Approach ◽  
Cultural Control ◽  
Computer Simulation Model ◽  
Weed Species ◽  
Hand Weeding ◽  
High Level

A computer simulation model was developed to investigate strategies for control of the parasitic weed species of Orobanche. The model makes use of data from published literature and predicts infestation levels in a dynamic and deterministic way. It is predicted that sustainable control of the parasite can only be achieved by reducing the soil seed bank to levels of 1000–2000 seeds m−2 and maintaining it at that level in subsequent years. When cultural control methods such as hand weeding, trap/catch cropping, delayed planting, resistant cultivars and solarization were considered individually, a relatively high level of effectiveness was required to contain the soil seed bank. An integrated approach with a selection of appropriate cultural methods is therefore recommended for further testing and validation in the field. The simulations demonstrate the importance of preventing new seeds entering the soil seed bank and that although reducing the soil seed bank may not increase yield for the first few years, it will ultimately increase production.

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

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.

scholarly journals Biodiversity of Segetal Weed Communities when Chlorsulfuron-Based Weed Control is Being Used on Continuous Winter Wheat

2014 ◽  
Vol 54 (3) ◽  
pp. 300-305
Author(s):  
Zbigniew Pawlonka ◽  
Katarzyna Rymuza ◽  
Krzysztof Starczewski ◽  
Antoni Bombik
Keyword(s):  
Winter Wheat ◽  
Initial Study ◽  
Short Term ◽  
Weed Communities ◽  
The Status ◽  
Weed Infestation ◽  
Weedy Species ◽  
The Relationship ◽  
Experimental Plots ◽  
Segetal Communities

Abstract The purpose of the study was to determine the relationship between herbicide rate and weed community biodiversity in continuous wheat. A six-year field experiment was conducted to examine the effect of four chlorsulfuron rates in comparison with untreated (the control) plots, on the status and severity of weed infestation - in successive study years of cultivating winter wheat in monoculture. In addition, the following indices were calculated: Shannon-Wiener and Simpson’s index of biodiversity, and Simpson’s index of domination. A total of 36 weedy species were identified in the experimental plots. The richest segetal communities were established in the control plots. An application of herbicide reduced the biodiversity of the agrophytocensosis. A short-term monoculture did not impoverish the species richness of the weed community established in winter wheat. The average number of species in the community was significantly greater in the second study year. In the initial study years of monoculture, the biodiversity of the segetal community increased markedly compared with rotation-based cultivation. The calculated indices of biodiversity were not significantly affected by herbicide rate or monoculture but the indices confirmed the trends outlined by an analysis of the status and level of weed infestation.

scholarly journals Biodiversity of weed communities in common wheat and spelt following various forecrops

2018 ◽  
Vol 71 (4) ◽  
Author(s):  
Maria Wanic ◽  
Mariola Parzonka ◽  
Dariusz Załuski
Keyword(s):  
Species Diversity ◽  
Common Wheat ◽  
Oilseed Rape ◽  
Dry Weight ◽  
Wiener Index ◽  
Weed Species ◽  
Spelt Wheat ◽  
Weed Communities ◽  
Weed Infestation ◽  
Heading Stage

Environmentally-friendly solutions are increasingly often applied in crop cultivation technologies. These include, among others, the return of old crops (e.g., spelt wheat) and crop rotation. Ensuring a proper forecrop is essential, especially in the cultivation of winter wheat, which is susceptible to infestation by weeds. However, there is only sparse information on infestation by weeds in the cultivation of winter spelt. In this study, it was assumed that this crop is invaded by weeds to a lesser extent than wheat, especially after unfavorable forecrops. The study was based on a field experiment conducted in the east part of Poland. The aim was to compare the weed infestation of common wheat and spelt wheat grown after peas, oilseed rape, and after itself. Analyses of weed infestation were conducted in 2014–2016. The weed species composition and population size were determined as well as their dry weight. The following indices were calculated: index of species richness, Simpson’s domination index, Shannon–Wiener index of species diversity, and Pielou’s index of evenness. The weed infestation of spelt wheat was higher than that of common wheat during the tillering stage. It was similar in both species during the heading stage. The lowest weed infestation in both cereals was observed on a field where peas had grown. Growing after oilseed rape and after themselves contributed to an increase in weed infestation. Biomass of weeds in a field of spelt was similar after all forecrops, unlike that in wheat, where more biomass was observed after oilseed rape and wheat. A greater share of <em>Apera spica-venti</em> and <em>Viola arvensis</em> was observed in common wheat and spelt grown after oilseed rape and after themselves. Weed communities in spelt were more diverse than in wheat. The forecrops did not differentiate the species diversity in either crop.

scholarly journals The seed bank of a gallery forest in Southeastern Brazil

2004 ◽  
Vol 47 (5) ◽  
pp. 793-797 ◽  
Author(s):  
Maria Tereza Grombone-Guaratini ◽  
Hermógenes de Freitas Leitão Filho ◽  
Paulo Yoshio Kageyama
Keyword(s):  
Community Composition ◽  
Forest Fragmentation ◽  
Seed Bank ◽  
Soil Seed Bank ◽  
Southeastern Brazil ◽  
Gallery Forest ◽  
Weed Species ◽  
Wet Season ◽  
Important Variation ◽  
Number Of Seeds

The soil seed bank was studied in a gallery forest in Southeastern Brazil. Samples were collected from edge to edge along transects perpendicular to the river during the wet (December, 1990) and dry (August, 1991) seasons. The number of seeds found in the seed bank samples was greater in the dry season than in the wet season indicating that there was important variation in the seed stocks in these two periods. The similarity values between the seed bank and the community composition were low. The high density of weed species might be reflecting forest fragmentation and indicating a degree of perturbation.

scholarly journals Seed loss and volunteer seedling establishment of rapeseed in the northernmost European conditions: potential for weed infestation and GM risks

2014 ◽  
Vol 23 (4) ◽  
pp. 327-339 ◽  
Author(s):  
Pirjo Peltonen-Sainio ◽  
Katri Pahkala ◽  
Hannu Mikkola ◽  
Lauri Jauhiainen
Keyword(s):  
Seed Bank ◽  
Seedling Establishment ◽  
Soil Seed Bank ◽  
Seedling Emergence ◽  
Major Effect ◽  
Seed Loss ◽  
Management Measures ◽  
Seed Bank Dynamics ◽  
Substantial Risk ◽  
Weed Infestation

Rapeseed soil seed bank development and volunteer plant establishment represent substantial risk for crop infestation and GM contamination. This study was designed to complement such investigations with novel understanding from high latitude conditions. Four experiments were designed to characterise seed loss at harvest, persistence, viability and capacity for volunteer seedling establishment, as well as impact of management measures on soil seed bank dynamics. Oilseed rape was the primary crop investigated due to the availability of GM cultivars and because of the increasing importance. Harvest losses and soil seed bank development were significant. Volunteer seedlings emerged at reasonably high rates, especially in the first autumn after harvest, but about 10% of buried seeds maintained their viability for at least three years. Soil incorporation methods had no major effect on numbers of volunteer seedlings, but herbicide treatments controlled volunteer seedlings efficiently, though not completely, due to irregular timing of seedling emergence.

scholarly journals Effect of Different Weed Management Strategies on Population Changing Pattern of Pennisetum polystachion in Coconut Plantations of Sri Lanka

CORD ◽  
2019 ◽  
Vol 35 (01) ◽  
pp. 8
Author(s):  
S.H.S. Senarathne
Keyword(s):  
Sri Lanka ◽  
Weed Management ◽  
Soil Seed Bank ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Soil Surface ◽  
Weed Species ◽  
Cover Cropping ◽  
Weed Seeds ◽  
Weed Infestation

Pennisetum polystachion is a major problematic monocotyledonous weed species and a perennial problem in intermediate zone of coconut plantations in Sri Lanka. This study was carried out to evaluate the impacts of different management systems on P. polystachion seedling emergence patterns.The tested treatments were application of glyphosate (T1), cover cropping with Pueraria phaseoloides (T2), tractor harrowing (T3), tractor slashing (T4) and tractor ploughing (T5). All the treatments were applied twice a year except T2. As T2 cover crop at the initiation of the experiment and over grown conditions were managed by harrowing once a year. Based on the reduction in weed biomass, cover cropping (T2) was the best to reduce the P. polystachion population and to reduce P. polystachion seedling emergence density in the field. Chemical weeding was the second-best method to control the P. polystachion population in the field. The effectiveness of slashing in reducing weed seedling emergence density was lower than cover cropping and chemical weeding methods. The weed seedling emergence densities were almost similar in ploughed and harrowed plots. The seed depth of emerged seedling was very high in harrowed and ploughed treatments when compared to other treatments. Results given by T3 and T5 indicates that loosening the soil creates more favorable environment for the germination of weed seeds buried in soil. Therefore, it can be argued that the elimination of weed seeds in the top 2cm or 4cm in the soil seed bank by any means is likely to reduce the level of weed infestation by about 60% to 95%. Results also indicated that burying rhizomes in ploughing and harrowing treatment plots at the depths below 30 - 40 cm is effective in controlling germination of this weed species. This experiment also suggested that keeping rhizomes on the soil surface without burying for durations of 5 – 15 days would produce weak plants with poor development.

Weed Seed Population Response to Tillage and Herbicide Use in Three Irrigated Cropping Sequences

Weed Science ◽  
1990 ◽  
Vol 38 (6) ◽  
pp. 511-517 ◽  
Author(s):  
Daniel A. Ball ◽  
Stephen D. Miller
Keyword(s):  
Seed Bank ◽  
Soil Seed Bank ◽  
Weed Seed ◽  
Weed Species ◽  
Pronounced Increase ◽  
Common Lambsquarters ◽  
Hairy Nightshade ◽  
Redroot Pigweed ◽  
Cropping Sequence ◽  
Herbicide Use

Research was conducted to evaluate the effects of primary tillage (moldboard plowing and chisel plowing), secondary tillage (row cultivation), and herbicides on weed species changes in the soil seed bank in three irrigated row cropping sequences over a 3-yr period. The cropping sequences consisted of continuous corn for 3 yr (CN), continuous pinto beans for 3 yr (PB), and sugarbeets for 2 yr followed by corn in the third year (SB). A comparison between moldboard and chisel plowing indicated that weed seed were more prevalent near the soil surface after chisel plowing. The density of certain annual weed seed over the 3-yr period increased more rapidly in the seed bank after chisel plowing compared to moldboard plowing. Species exhibiting the most pronounced increase included hairy nightshade and stinkgrass in the PB cropping sequence and redroot pigweed and common lambsquarters in the SB sequence. Conversely, kochia seed density in the SB sequence decreased more rapidly in chisel-plowed plots. Row cultivation generally reduced seed bank densities of most species compared to uncultivated plots. Herbicide use in each cropping sequence produced a shift in the weed seed bank in favor of species less susceptible to applied herbicides. In particular, seed of hairy nightshade became prevalent in the PB cropping sequence, and seed of kochia, redroot pigweed, and common lambsquarters became prevalent in the SB sequence.

Wetland Weeds

2011 ◽  
Author(s):  
Nick Romanowski
Keyword(s):  
Weed Control ◽  
Seed Bank ◽  
Aquatic Ecosystems ◽  
Native Plants ◽  
Soil Seed Bank ◽  
Pragmatic Approach ◽  
Short Term ◽  
Future Potential ◽  
Culinary Uses ◽  
Taking Action

This comprehensive guide to wetland weeds covers both native and introduced species, ranging from minor or localised environmental problems to those that should not be tolerated in any situation. The author takes a pragmatic approach to weed control, recognising that some weeds may not be possible to eradicate, and emphasising the need to assess the extent and future potential of any infestation before taking action. Weed control should be planned in the context of the overall management goals for any type of wetland, the types of habitat weeds provide or overrun, and whether they can be replaced successfully with more appropriate plants. A range of strategies for controlling wetland weeds are considered, from containment actions to prevent the development of a soil seed bank to physical removal, and biological approaches from biocontrol to shading, overplanting and use of turbidity. The widespread use of chemical controls is also discussed, with the warning that these are often only a short-term cure and can cause more harm to aquatic ecosystems than the weeds they are holding at bay. More than 130 species of established weeds are included with information on their origins, nutrient responses, environmental effects, habitat values, prospects for containment or eradication, and even culinary uses. Other sections look at native plants as weeds, including a number of species of uncertain origins, and potential weeds still being legally sold through the aquarium and nursery trades.

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