Environmental factors including management practices as correlates of weed community composition in spring seeded crops

1992 ◽  
Vol 70 (10) ◽  
pp. 1931-1939 ◽  
Author(s):  
M. R. T. Dale ◽  
A. G. Thomas ◽  
E. A. John
Keyword(s):  
Community Composition ◽  
Correspondence Analysis ◽  
Canonical Correspondence Analysis ◽  
Environmental Variables ◽  
Management Practices ◽  
Geographic Region ◽  
Climatic Conditions ◽  
Weed Species ◽  
Weed Communities ◽  
Seed Crops

The relationship between the weed communities and environmental variables such as soil, crop, and management was investigated in two provinces of Canada. The frequencies of weed species were recorded in cereal and oilseed fields in Saskatchewan (2244 fields over 4 years) and Manitoba (864 fields over 3 years), Canada. Information on some of the physical characteristics of the fields and on the management practices imposed on them was also collected, in part by questionnaire. The two kinds of data were ordinated together using canonical correspondence analysis to assess the relationships between the species and the environmental variables. In the Saskatchewan data, there was a clear and consistent separation of the species into groups along an axis correlated with soil zone and the associated climatic gradient. In the Manitoba data, the same groups of species did not separate as clearly or as consistently, although geographic region was a major determinant of the weed communities. The greater variability may be due to the fact that the gradient of soil types is much more restricted in Manitoba and not as closely correlated with climatic conditions. In both provinces, culture practices were less important as correlates of the weed community composition than soil type or, to a certain extent, the previous crop. Key words: canonical correspondence analysis, cereal crops, oil seed crops.

Weed communities associated with arable Saskatchewan farm management systems

2000 ◽  
Vol 80 (1) ◽  
pp. 177-185 ◽  
Author(s):  
J. Y. Leeson ◽  
J. W. Sheard ◽  
A. G. Thomas
Keyword(s):  
Life History ◽  
Correspondence Analysis ◽  
Canonical Correspondence Analysis ◽  
Management System ◽  
Management Practices ◽  
Farming System ◽  
Management Systems ◽  
Weed Communities ◽  
History Of ◽  
The Impact

The objective of this study was to determine the impact of a range of management systems on weed communities in cropped fields on farms in Saskatchewan. Farms (n = 28) with management systems defined by a combination of different cropping histories and chemical input levels were selected. Fields were surveyed on each farm in 1995, 1996, and 1997 after any post-emergent weed control to ensure that their weed communities reflected the impact of all agronomic management practices typical of the management system. Canonical correspondence analysis was used to determine whether weed communities were significantly correlated with management system after removal of variance due to ecoregion and year. The largest difference in weed communities attributable to farming system was between the systems with annual cropping histories and those that included perennials in the cropping history. Thus, the life history of the weeds reflected the life history of the crops. Herbicide use was correlated with the next largest difference between systems. A significant association between weed communities and different management systems indicates that weed species are being selected for by these systems. If such selection pressure continues, these species may become a threat to the system's sustainability. Key words: Weed communities, chemical input level, cropping history, canonical correspondence analysis, correspondence analysis, farming system

Weed species diversity in spring barley varies with crop rotation and tillage, but not with nutrient source

Weed Science ◽  
1997 ◽  
Vol 45 (6) ◽  
pp. 798-806 ◽  
Author(s):  
F. Craig Stevenson ◽  
Anne Légère ◽  
Régis R. Simard ◽  
Denis A. Angers ◽  
Denis Pageau ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Crop Rotation ◽  
Spring Barley ◽  
Climatic Conditions ◽  
Dairy Manure ◽  
Weed Species ◽  
Nutrient Source ◽  
Weed Communities ◽  
Weed Species Richness

The development of sustainable farming systems depends on our ability to predict and manage the response of weed communities to changes in cropping practices. A study was established at Normandin, Québec, Canada, to investigate the influence of liquid dairy manure and mineral fertilizer, as well as chisel and moldboard plow tillage systems, in a spring barley monoculture and a 3-yr spring barley-forage rotation that included red clover and timothy. Weed species richness (Margalef's DMG), evenness (Shannon's E), and diversity (Shannon's H') were examined in these treatments from 1992 to 1995. Nutrient source had no effect on any of the three diversity indices. Evenness values were extremely low in all years, suggesting dominance of a few weed species in most treatments. Weed species richness and diversity generally were greater in the barley-forage rotation compared with the monoculture. Tillage effects on richness and diversity varied with crop rotation. Margalef's DMGand Shannon's H' were greater in 1993 and 1995, but they were lower in 1994 when chisel was compared with moldboard plowing in the monoculture. In 1994, chickweed density was about five times greater in the chisel-plowed monoculture compared with other treatment combinations of rotation and tillage. In 1995, only one species with a density of six plants m−2occurred in the moldboard-plowed monoculture compared with three to six species and densities of 51 to 832 plants m−2in the other rotation by tillage treatments. Climatic conditions and herbicide use patterns in the different crop rotation treatments may have contributed to the more dynamic nature of weed species diversity in the barley monoculture. Reduced frequency of tillage and herbicide application; management of the forage stands, especially with regard to their termination; and improved soil resource availability likely explained the increased but more stable diversity of the weed communities in the barley-forage rotation.

Seedbank and Emerged Weed Communities Following Adoption of Glyphosate-Resistant Crops in a Long-Term Tillage and Rotation Study

Weed Science ◽  
2009 ◽  
Vol 57 (3) ◽  
pp. 261-270 ◽  
Author(s):  
Lynn M. Sosnoskie ◽  
Catherine P. Herms ◽  
John Cardina ◽  
Theodore M. Webster
Keyword(s):  
Community Composition ◽  
Indicator Species ◽  
Conventional Tillage ◽  
Management Program ◽  
No Tillage ◽  
Weed Species ◽  
Continuous Corn ◽  
Weed Communities ◽  
Rotation Study

The compositions of the germinable weed seedbank and aboveground weed communities in a long-term tillage and rotation study were characterized 4, 5, and 6 yr (2002 to 2004) after the adoption of glyphosate-tolerant corn and soybean. Averaged across rotation, mean germinable weed seed density and diversity were greatest in the no-tillage treatment as compared to the minimum- and conventional-tillage treatments. Averaged over tillage, density and diversity were greater in the corn–oat–hay (ryegrass + alfalfa) system as compared to the continuous corn and corn–soybean rotations. Similar trends in density and diversity were observed for the aboveground weed communities. Differences in community composition among treatments were quantified with the use of a multiresponse permutation procedure. Results indicated that the weed seedbank community in a corn–oat–hay rotational system differed from the communities associated with the continuous corn and corn–soybean rotational systems. Weed seedbank communities developing under a no-tillage operation differed from those in minimum- and conventional-tillage scenarios. Compositional differences among the aboveground weed communities were less pronounced in response to tillage and rotation. Indicator species analyses indicated that the number of significant indicator weed species was generally higher for no tillage than minimum or conventional tillage for both the seedbank and the aboveground weed communities. The number of significant indicator species for the seedbank and weed communities was generally greater in the three-crop rotation as compared to the continuous corn and corn–soybean rotations. The trends observed in density, diversity, and community composition after the adoption of glyphosate-tolerant corn and soybeans, and a glyphosate-dominated weed management program, were also observed when soil-applied herbicides were included in the study. We suggest that the switch to a POST-glyphosate protocol did not significantly alter weed communities in the short term in this study.

WEED COMMUNITY ANALYSIS IN MAIZE CROP IN NATURAL CLIMATE OF KHAIRPUR DISTRICT, PAKISTAN

2021 ◽  
Vol 27 (1) ◽  
pp. 35-41
Author(s):  
Naeema Khatoon Khaskheli ◽  
Muzafar Hussain Sirohi ◽  
Abdul Razak MAhar ◽  
Ameer Ahmed Mirbahar ◽  
Mumtaz Ali Saand ◽  
...  
Keyword(s):  
Community Composition ◽  
Weed Management ◽  
Management Practices ◽  
Community Analysis ◽  
Growth And Yield ◽  
Weed Species ◽  
Maize Crop ◽  
Trianthema Portulacastrum ◽  
Plant Families ◽  
Study Sites

Weeds are the noxious plants that stunt growth and yield of many crops. This study recorded the community composition of weeds in maize crops grown at District Khairpur, Sindh Pakistan. The weeds were collected from the maize crops at three different localities using the quadrat method (60 quadrats/site). The species were identified and herbarium samples were preserved in Herbarium, Shah Abdul Latif University, Khairpur, Sindh Pakistan, for future reference. The species community composition, habit, and life span were determined. The study confirmed 35 weed species belonging to 14 plant families. The weed community was dominated by the plant families Poaceae (8 spp.), Amaranthaceae (7 spp.), and Aizoaceae (3 spp.). The most frequent species with relatively higher densities include Digera muricata (Amaranthaceae), Trianthema portulacastrum (Aizoaceae), and Corchorus olitorius (Malvaceae). The weed community was dominated with annual herbs. The community composition among the study sites was highly comparable. The study found a lack of weed management practices across the sites.

Species-environment relationships in three woodlands using canonical correspondence analysis

1990 ◽  
Vol 55 ◽  
Author(s):  
R. Keymeulen ◽  
H. Beeckman
Keyword(s):  
Plant Communities ◽  
Correspondence Analysis ◽  
Canonical Correspondence Analysis ◽  
Environmental Variables ◽  
Ecological Study ◽  
Basal Area ◽  
Environmental Variable ◽  
Light Penetration ◽  
Indicator Values

Relations  between plant communities and environment were investigated in an ecological  study in three woodlands in the south of Flanders, Belgium. The vegetation  was sampled and three environmental variables (light penetration, chemical  composition of the soil and species composition of the tree and shrub layer)  were measured. By application of canonical correspondence analysis (CCA),  relations between the vegetation and the environmental variables could be  evaluated. The percentage of Fagus sylvatica in the basal area seemed to be the most decisive environmental  variable determining the presence of plant communities. It could be derived  as well that CCA can be a very useful technique for the determination of the  indicator values of the species for their environment.

Weed Communities in Strip-Tillage Corn/No-Tillage Soybean Rotation and Chisel-Plow Corn Systems after 10 Years of Variable Management

Weed Science ◽  
2018 ◽  
Vol 66 (5) ◽  
pp. 651-661
Author(s):  
Nathaniel M. Drewitz ◽  
David E. Stoltenberg
Keyword(s):  
Community Composition ◽  
Chenopodium Album ◽  
Cropping System ◽  
Production Costs ◽  
No Tillage ◽  
Weed Species ◽  
Weed Communities ◽  
Chisel Plow ◽  
Strip Tillage

AbstractPrevious research has shown that strip-tillage (ST) systems conserve soil, reduce production costs, and save time for growers compared with intensive-tillage systems. In contrast to these well-documented benefits, we have limited information on weed community dynamics and management risks in ST corn (Zea maysL.) production systems in the northern Corn Belt. Therefore, we conducted research in 2015 and 2016 to characterize weed community composition, emergence patterns, and aboveground productivity in an ST corn/no-tillage (NT) soybean [Glycine max(L.) Merr.] rotation that was established in 2007 compared with a long-term intensive-tillage chisel-plow (CP) continuous-corn system. Fifteen or more weed species were identified in nontreated quadrats in each cropping system in each year. Common lambsquarters (Chenopodium albumL.) was the most abundant weed species across systems and years.Chenopodium albumdensities were similar between CP and ST corn phases and were approximately 2-fold greater compared with the NT soybean phase. Other abundant weed species occurred at much lower densities thanC. album. In each year, cumulative emergence of nontreated weed communities was described best by a logistic function in each cropping system. Maximum weed community emergence was greater in CP corn than ST corn phases in 2015, but did not differ in 2016. In the ST corn phase, most (about 75%) weed community emergence occurred in the in-row (tilled) zone compared with the between-row (nondisturbed) zone. Total late-season weed shoot biomass did not differ between nontreated CP and ST corn phases in either year, withC. albumaccounting for >85% of total weed biomass in these phases. These results suggest that weed community composition, total emergence, and productivity were similar between CP and ST corn phases after 10 yr. Our findings, coupled with previous research that showed favorable agronomic performance and greater soil conservation associated with the long-term ST corn/NT soybean system, suggest that production risks are no greater than a CP corn system, while processes that underpin ecosystem services are enhanced. These results provide strong evidence to support grower adoption of ST practices as an alternative to intensive tillage.

scholarly journals Determinants of terrestrial arthropod community composition at Cape Hallett, Antarctica

2006 ◽  
Vol 18 (3) ◽  
pp. 303-312 ◽  
Author(s):  
Brent J. Sinclair ◽  
Matthew B. Scott ◽  
C. Jaco Klok ◽  
John S. Terblanche ◽  
David J. Marshall ◽  
...  
Keyword(s):  
Community Composition ◽  
Correspondence Analysis ◽  
Canonical Correspondence Analysis ◽  
Management Plan ◽  
Arthropod Community ◽  
Free Living ◽  
Spatial Variables ◽  
Victoria Land ◽  
Penguin Colony ◽  
Free Area

The distribution and abundance of free-living arthropods from soil and under stones were surveyed at the Cape Hallett ice-free area (ASPA No. 106), North Victoria Land, Antarctica. A total of 327 samples from 67 plots yielded 11 species of arthropods comprised of three Collembola: Cryptopygus cisantarcticus, Friesea grisea and Isotoma klovstadi and eight mites: Coccorhagidia gressitti, Eupodes wisei, Maudheimia petronia, Nanorchestes sp., Stereotydeus belli, S. punctatus, Tydeus setsukoae and T. wadei. Arthropods were absent from areas occupied by the large Adélie penguin colony. There was some distinction among arthropod communities of different habitats, with water and a lichen species (indicative of scree slope habitats) ranking as significant community predictors alongside spatial variables in a Canonical Correspondence Analysis. Recent changes to the management plan for ASPA No. 106 may need to be revisited as the recommended campsite is close to the area of greatest arthropod diversity.

scholarly journals Timing of Tillage as a Driver of Weed Communities

Weed Science ◽  
2017 ◽  
Vol 65 (4) ◽  
pp. 504-514 ◽  
Author(s):  
Stéphane Cordeau ◽  
Richard G. Smith ◽  
Eric R. Gallandt ◽  
Bryan Brown ◽  
Paul Salon ◽  
...  
Keyword(s):  
Community Structure ◽  
Community Composition ◽  
Management Practice ◽  
Cropping Systems ◽  
Block Design ◽  
Growing Season ◽  
Soil Tillage ◽  
Weed Species ◽  
Weed Communities ◽  
The Impact

Tillage is a foundational management practice in many cropping systems. Although effective at reducing weed populations and preparing a crop seedbed, tillage and cultivation can also dramatically alter weed community composition. We examined the impact of soil tillage timing on weed community structure at four sites across the northeastern United States. Soil was tilled every 2 wk throughout the growing season (late April to late September 2013), and weed seedling density was quantified by species 6 wk after each tillage event. We used a randomized complete block design with four replicates for each tillage-timing treatment; a total of 196 plots were sampled. The timing of tillage was an important factor in shaping weed community composition and structure at all sites. We identified three main periods of tillage timing that resulted in similar communities. Across all sites, total weed density tended to be greatest and weed evenness tended to be lowest when soils were tilled early in the growing season. From the earliest to latest group of timings, total abundance decreased on average from 428±393 to 159±189 plants m−2, and evenness increased from 0.53±0.25 to 0.72±0.20. The effect of tillage timing on weed species richness varied by site. Our results show that tillage timing affects weed community structure, suggesting that farmers can manage weed communities and the potential for weed interference by adjusting the timing of their tillage and cropping practices.

scholarly journals Arable Weed Patterns According to Temperature and Latitude Gradient in Central and Southern Spain

Atmosphere ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 853
Author(s):  
María Luisa Gandía ◽  
Carlos Casanova ◽  
Francisco Javier Sánchez ◽  
José Luís Tenorio ◽  
María Inés Santín-Montanyá
Keyword(s):  
Climate Change ◽  
Climatic Conditions ◽  
Effect Of Temperature ◽  
Weed Species ◽  
Stellaria Media ◽  
Climate Gradients ◽  
Weed Communities ◽  
Arable Weed ◽  
Temperature Ranges ◽  
Local Species

(1) Background: In agro-ecosystems, the success of the crops has a strong connection to biodiversity in the landscape. In the face of climate change, it is important to understand the response to environmental variation of weed species by means of their distribution. In the last century, biodiversity has been impacted due to a variety of stresses related to climate change. Although the composition of vegetation tends to change at a slower rate than climate change, we hypothesize species present in weed communities are distributed in diverse patterns as a response to the climate. Therefore, the general aim of this paper is to investigate the effect of temperature, using latitude as an indicator, on the composition and distribution of weed communities in agro-ecosystems. (2) Methods: Weeds were monitored in georeferenced cereal fields which spanned south and central Spanish regions. The graphic representation according to latitude allowed us to identify groups of weeds and associate them to a temperature range. We classified weeds as generalist, regional, or local according to the range of distribution. (3) Results: The monitoring of species led to the classification of weeds as generalist, regional or local species according to latitude and associated temperature ranges. Three weed species that were present in all latitude/temperature regions, were classified as generalist (Linaria micrantha (Cav) Hoffmanns & Link, Sonchus oleraceous L., and Sysimbrium irium L.). The species were classified as regional or local when their presence was limited to restricted latitude/temperature ranges. One weed, Stellaria media (L.) Vill., was considered a local species and its distribution dynamics can be considered an indicator of temperature. (4) Conclusions: The novel methodology used in this study to assign weed distribution as an indicator of climatic conditions could be applied to evaluate climate gradients around the world.

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