Mapping the occurrence and spatial distribution of noxious weed species with multisource data in degraded grasslands in the Three-River Headwaters Region, China

2021 ◽  
Vol 801 ◽  
pp. 149714
Author(s):  
Fei Xing ◽  
Ru An ◽  
Benlin Wang ◽  
Jun Miao ◽  
Tong Jiang ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Weed Species ◽  
Noxious Weed

scholarly journals Herbicides for lamb's quarters control in soybean crops

2021 ◽  
Vol 51 (4) ◽  
pp. 33-41
Author(s):  
V. N. Morokhovets ◽  
Z. V. Basay ◽  
T. V. Morokhovets ◽  
A. A. Baimulianova ◽  
N. S. Skorik ◽  
...  
Keyword(s):  
Chenopodium Album ◽  
Far East ◽  
Weed Species ◽  
Average Growth ◽  
Soybean Seedlings ◽  
Series Of Experiments ◽  
Toxicity Level ◽  
Lamb’S Quarters ◽  
Noxious Weed ◽  
Active Substances

The results of the study of toxicity level for the lamb's quarters (Chenopodium album L.) of well-known herbicides used in soybean crops as well as herbicides promising for soybean production in the Far East are presented. Lamb's quarters (Chenopodium album L.) is a highly noxious weed species that is widespread in the south of the region. Weediness monitoring conducted in 2006-2020 showed that this species was present in the Primorsky Territory on 63-100% of fields occupied by soybeans with an average growth density of 3-117 pcs/m2. In 2013-2020 in a series of experiments, conducted in the conditions of the vegetation house and on the experimental fields of the institute, the toxicity level for Common lamb's quarters was determined by 20 herbicides (based on 14 active substances) used in soybean crops. It was found that the control of this weed species is most effective when applying herbicides in the soil and treating plants with a height of up to 4-11 cm at the early stages of development - 1-3 pairs of leaves. Reliable suppression of lamb's quarters in experiments was provided by the soil (before sowing or before soybean seedlings) use of herbicides containing active substances metribuzin, imazetapir, trifluralin, pendimetalin and acetochlor. Among the active ingredients of the tested foliar herbicides, fomesafen, combinations of bentazone + acifluorfen and imazamox + chlorimuron-ethyl were the most toxic for lamb's quarters. It is recommended to use the following herbicidal preparations to control the spread of lamb's quarters: before sowing or sprouting of soybeans - Lazurit, Zenkor Ultra, Pivot, Proponit, Fabian; for processing vegetative plants - Flex, Galaksi Top, Concept, Classic Forte (Harmony Classic), Proponit.

scholarly journals Biology and Management of Praxelis (Praxelis clematidea) in Ornamental Crop Production

EDIS ◽  
2020 ◽  
Vol 2020 (4) ◽  
Author(s):  
Yuvraj Khamare ◽  
Chris Marble ◽  
Shawn Steed ◽  
Nathan Boyd
Keyword(s):  
Crop Production ◽  
Plant Protection ◽  
Ornamental Plants ◽  
Weed Species ◽  
Green Industry ◽  
Noxious Weed ◽  
Industry Professionals

Praxelis is a newly emerging weed species in Florida, one that Plant Protection and Quarantine (PPQ) is considering adding to the federal noxious weed list. The plant can be easily misidentified and confused with Ageratum houstonianum (bluemink) and Conoclinium coelestinum (blue mistflower) as well as several other species that have similar flower characteristics. This new 5-page article is written for green industry professionals and others to aid in the identification and management of praxelis in and around ornamental plants. Written by Yuvraj Khamare, Chris Marble, Shawn Steed, and Nathan Boyd, and published by the UF/IFAS Environmental Horticulture Department.https://edis.ifas.ufl.edu/ep585

scholarly journals Infestation maps and spatial stability of main weed species in maize culture

2014 ◽  
Vol 32 (2) ◽  
pp. 275-282 ◽  
Author(s):  
I.M. Calha ◽  
E. Sousa ◽  
J.L. González-Andújar
Keyword(s):  
Spatial Distribution ◽  
Chenopodium Album ◽  
Species Number ◽  
First Year ◽  
Distribution Analysis ◽  
Herbicide Application ◽  
Weed Species ◽  
Spatial Stability ◽  
Representative Species ◽  
The Difference

A study on the spatial distribution of the major weeds in maize was carried out in 2007 and 2008 in a field located in Golegã (Ribatejo region, Portugal). The geo-referenced sampling focused on 150 points of a 10 x 10 m mesh covering an area of 1.5 ha, before herbicide application and before harvest. In the first year, 40 species (21 botanical families) were identified at seedling stage and only 22 during the last observation. The difference in species richness can be attributed to maize monoculture favouring reduction in species number. Three of the most representative species were selected for the spatial distribution analysis: Solanum nigrum, Chenopodium album and Echinochloa crus-galli. The three species showed an aggregated spatial pattern and spatial stability over both years, although the herbicide effect is evident in the distribution of some of them in the space. These results could be taken into account when planning site-specific treatments in maize.

scholarly journals EVOLUTION OF WEED FLORA IN SUGAR BEET CROPS UNDER DIFFERENT DEGREESOF ANTHROPOGENIC LOAD IN THE 20TH CENTURY AND EARLY 21STCENTURY

2021 ◽  
pp. 5-12
Author(s):  
D.V. Bochkarev ◽  
◽  
Yu.N. Nedayborshch ◽  
A.N. Nikolskiy ◽  
A.N. Slugin ◽  
...  
Keyword(s):  
Sugar Beet ◽  
Species Composition ◽  
Crop Protection ◽  
Crop Productivity ◽  
Early Spring ◽  
Weed Species ◽  
Couch Grass ◽  
The North ◽  
Elytrigia Repens ◽  
Noxious Weed

The south of the Non-Chernozem Region is the north-ern boundary of sugar beet production in the Russian Fed-eration. An important factor restraining the growth of crop productivity is the high weed infestation of crops. To devel-op an effective system of crop protection against weeds, it is necessary to study their species composition in order to determine the most occurring and noxious weed species. The available data of geobotanical surveys since the 1930s showed that at different levels of anthropogenic impact the core of the most noxious weed species was formed. Under extensive agriculture conditions, the following species were the most widespread ones: Elytrigia repens(L.) Nevski, Equiseeum arvenseL., Sonchus arvensis L., Convolvulus arvensisL., Cirsium setosum(Willd.) Besser., Artemisia absinthiumL., Chenopodium albumL., Polygonum avicula-reL., Apera spica-ventiL., etc. The introduction of mechan-ical plowing decreased the population density of A. spica-ventiL., Dracocephalum thymiflorumL., and P. aviculareL. Further intensification of agriculture contributed to the narrowing of the weed species composition. Avena fatuaL., not previously found, appeared in abundance in crops and surpassed all other species in terms of number and frequency of occurrence, as well as species resistant to herbicides from the 2.4-D dimethylamine group -Poaceae, Galium aparineL., Tripleurospermum inodorum(L.) Sch. Bip. Couch grass(Elytrigia repens(L.) Nevski) was com-pletely substituted. Currently, the agrophytocenoses con-tain the most harmful rhizome and root-sucker weeds and spring species. Thefollowing early spring weeds are par-ticularly harmful and highly spread in crops: common wild oat (Avena fatuaL.), hemp-nettle species (Galeopsis), and Chenopodium albumL.; overwintering weeds resistant to 2.4-D dimethylamine which seeds accumulate in the soil during the cultivation of other crops in crop rotations where weed control is not so intense.

The impact of sown grass strips on the spatial distribution of weed species in adjacent boundaries and arable fields

2012 ◽  
Vol 155 ◽  
pp. 35-40 ◽  
Author(s):  
Stéphane Cordeau ◽  
Sandrine Petit ◽  
Xavier Reboud ◽  
Bruno Chauvel
Keyword(s):  
Spatial Distribution ◽  
Weed Species ◽  
Arable Fields ◽  
The Impact

Weed Decision Threshold as a Key Factor for Herbicide Reductions in Site-Specific Weed Management

2016 ◽  
Vol 30 (4) ◽  
pp. 888-897 ◽  
Author(s):  
Carolina San Martín ◽  
Dionisio Andújar ◽  
Judit Barroso ◽  
Cesar Fernández-Quintanilla ◽  
José Dorado
Keyword(s):  
Spatial Distribution ◽  
Weed Management ◽  
Crop Yields ◽  
Decision Threshold ◽  
Weed Species ◽  
Site Specific ◽  
Patch Spraying ◽  
Key Factor ◽  
Sampling Procedures ◽  
Herbicide Use

The objective of this research was to explore the influence that weed decision threshold (DT; expressed as plants m−2), weed spatial distribution patterns, and spatial resolution of sampling have on potential reduction in herbicide use under site-specific weed management. As a case study, a small plot located in a typical corn field in central Spain was used, constructing very precise distribution maps of the major weeds present. These initial maps were used to generate herbicide prescription maps for each weed species based on different DTs and sampling resolutions. The simulation of herbicide prescription maps consisted of on/off spraying decisions based on information from two different approaches for weed detection: ground-based vs. aerial sensors. In general, simulations based on ground sensors resulted in higher herbicide savings than those based on aerial sensors. The extent of herbicide reductions derived from patch spraying was directly related to the density and the spatial distribution of each weed species. Herbicide savings were potentially high (up to 66%) with relatively sparse patchy weed species (e.g., johnsongrass) but were only moderate (10 to 20%) with abundant and regularly distributed weed species (e.g., velvetleaf). However, DT has proven to be a key factor, with higher DTs resulting in reductions in herbicide use for all the weed species and all sampling procedures and resolutions. Moreover, increasing DT from 6 to 12 plants m−2resulted in additional herbicide savings of up to 50% in the simulations for johnsongrass and up to 28% savings in the simulations for common cocklebur. Nonetheless, since DT determines the accuracy of patch spraying, the consequences of using higher DTs could be leaving areas unsprayed, which could adversely affect crop yields and future weed infestations, including herbicide-resistant weeds. Considering that the relationship between DT and accuracy of herbicide application depends on weed spatial pattern, this work has demonstrated the possibility of using higher DT values in weeds with a clear patchy distribution compared with weeds distributed regularly.

A Containment Facility for Research on Foreign Noxious Weeds

1987 ◽  
Vol 1 (1) ◽  
pp. 52-55 ◽  
Author(s):  
Richard A. Creager
Keyword(s):  
North American ◽  
Standard Operating Procedure ◽  
Control Technology ◽  
Weed Species ◽  
Noxious Weeds ◽  
Weed Seeds ◽  
Standard Operating ◽  
Growth Chambers ◽  
Noxious Weed ◽  
American Agriculture

Two conventional greenhouses were modified into a containment facility for the study of foreign noxious weed species that could be dangerous to North American agriculture. The facility was designed for research on the biology, ecology, and weed control technology of foreign noxious weeds, without the escape of propagules. Two growth chambers and a germinator are located within the containment facility for evaluations under controlled environmental conditions. A standard operating procedure is followed to preclude the escape of weed seeds or propagules while minimizing restrictions to research. The facilities are locked and located in a secure fenced area to reduce the probability of accidental or intentional damage. Procedures for emergencies have been designed to facilitate aid without compromising the containment security. Knowledge concerning weeds that have the potential to threaten North American agriculture will be gained from research performed within this facility.

Spatial Pattern of Weeds Based on Multispecies Infestation Maps Created by Imagery

Weed Science ◽  
2016 ◽  
Vol 64 (3) ◽  
pp. 474-485 ◽  
Author(s):  
Louis Longchamps ◽  
Bernard Panneton ◽  
Robin Reich ◽  
Marie-Josée Simard ◽  
Gilles D. Leroux
Keyword(s):  
Spatial Distribution ◽  
Image Segmentation ◽  
Spatial Pattern ◽  
Weed Management ◽  
Herbicide Application ◽  
Weed Species ◽  
Site Specific ◽  
Weed Cover ◽  
Weed Infestation ◽  
Level Of Aggregation

Weeds are often spatially aggregated in maize fields, and the level of aggregation varies across and within fields. Several annual weed species are present in maize fields before postemergence herbicide application, and herbicides applied will control several species at a time. The goal of this study was to assess the spatial distribution of multispecies weed infestation in maize fields. Ground-based imagery was used to map weed infestations in rain-fed maize fields. Image segmentation was used to extract weed cover information from geocoded images, and an expert-based threshold of 0.102% weed cover was used to generate maps of weed presence/absence. From 19 site-years, 13 (68%) demonstrated a random spatial distribution, whereas six site-years demonstrated an aggregated spatial pattern of either monocotyledons, dicotyledons, or both groups. The results of this study indicated that monocotyledonous and dicotyledonous weed groups were not spatially segregated, but discriminating these weed groups slightly increased the chances of detecting an aggregated pattern. It was concluded that weeds were not always spatially aggregated in maize fields. These findings emphasize the need for techniques allowing the assessment of weed aggregation prior to conducting site-specific weed management.

Spatial Distribution Patterns of Weed Communities in Corn Fields of Central Spain

Weed Science ◽  
2015 ◽  
Vol 63 (4) ◽  
pp. 936-945 ◽  
Author(s):  
Carolina San Martín ◽  
Dionisio Andújar ◽  
Cesar Fernández-Quintanilla ◽  
José Dorado
Keyword(s):  
Spatial Distribution ◽  
Distribution Patterns ◽  
Scale Dependence ◽  
Individual Species ◽  
Weed Species ◽  
Central Spain ◽  
Purple Nutsedge ◽  
Spatial Distribution Patterns ◽  
Distribution Maps ◽  
Sampling Grid

The overall objective of this study was to identify common patterns in the spatial distribution of the major weed species present in the corn-growing region of central Spain, exploring the scale dependence of these patterns and the possible associations or dissociations between individual species. Weed density was assessed in 16 commercial fields using digital images acquired in a 9-m by 9-m sampling grid. A set of six species was found in all the fields: black nightshade, common cocklebur, fierce thornapple, johnsongrass, purple nutsedge, and velvetleaf. Spatial analysis by distance indices and inverse distance weighting interpolation methods were performed to create weed distribution maps. The results showed aggregated spatial distribution patterns for all individual species regardless their life cycle, annual or perennial. Some associations and dissociations among species were found in the analysis of interactions. Nevertheless, the spatial patterns of co-occurrence of weed species were field-specific and therefore cannot be considered general patterns of weed co-occurrence. In order to explore the scale dependence of these results, an additional study was conducted in an experimental field located in the same area using a 1.0-m by 0.75-m sampling grid. Although this resolution allowed for a better definition of the positions of the weed patches and weed-free gaps, the results obtained revealed similar patterns to those observed with a coarser sampling resolution.

scholarly journals An invasive shrub Lantana camara L. alters the flora and soils in tropical dry deciduous forests of Central India

2021 ◽  
Author(s):  
Parvaiz Ahmad Lone ◽  
Javid Ahmad Dar ◽  
Subashree Kothandaraman ◽  
Mohammed Latif Khan
Keyword(s):  
Soil Properties ◽  
Bulk Density ◽  
Native Species ◽  
Basal Area ◽  
Central India ◽  
Lantana Camara ◽  
Deciduous Forests ◽  
Weed Species ◽  
Invasive Weed ◽  
Noxious Weed

Abstract Background and AimsLantana camara is a highly noxious invasive weed species of global concern. However, its impacts on floristic and soil properties in tropical dry deciduous forests are elusive and fragmented. We aimed to assess the changes in the flora and soil properties following the invasion by Lantana camara in Central Indian forest ecosystems.MethodsThree study sites were selected and each site was further divided into two subsites: Lantana-invaded (LI) and uninvaded (UI). In total, 60 plots of 0.25 ha each (10 plots in each subsite) were laid randomly. Within each plot floristic structure, composition, diversity and soil SOC, STN, M%, pH and bulk density were assessed.ResultsLantana-invaded sites showed a significant decrease in density (D), basal area (BA), species richness (SR) and evenness (E) of seedlings (< 3cm diameter at breast height (DBH)), juveniles (> 3-9.9cm DBH), and herbs. In LI sites, a reduction of 57 and 25% has been observed in lower DBH class of trees (< 3cm and > 3-9.9cm). In all LI sites, a significant increase of soil organic carbon (SOC), soil total nitrogen (STN) and soil moisture (M%) and a significant decrease of pH and bulk density (BD) were recorded.ConclusionsLantana may greatly impact the vegetation and soil properties and, successively, these strong changes increase its invasive potential and ability to replace native species by averting their natural regeneration potential. Therefore, a proper management strategy of this noxious weed is imperative to prevent its further expansion and future problems.

Sign in / Sign up

Export Citation Format

Share Document