scholarly journals Multivariate analysis of vegetation of the salted lower-cheliff plain, Algeria

2019 ◽  
Vol 85 ◽  
pp. 59
Author(s):  
Adda Ababou ◽  
Mohammed Chouieb ◽  
Mohammed Khader ◽  
Khalladi Mederbal ◽  
Djamel Saidi ◽  
...  
Keyword(s):  
Plant Communities ◽  
Soil Structure ◽  
Redundancy Analysis ◽  
Multivariate Analyses ◽  
Detrended Correspondence Analysis ◽  
Vegetation Distribution ◽  
Edaphic Factors ◽  
Soil Factors ◽  
Soil Variables ◽  
Close Relationship

The main objectives of this study were to identify the edaphic factors that could be related to vegetation distribution in the lower-Cheliff plain (35.750° - 36.125°N, 0.5° - 1°E) one the largest salted plains of northwestern Algeria and to establish the relationships between these soil factors and the main plant communities. Soil and vegetation data were obtained from 133 relevés. Species in Chenopodiaceae and Asteraceae were dominant in the salted plain. Soil variables measured included electrical conductivity, elevation, soil texture, soil structure, organic matter, CaCO3, pH, Ca++, Na+, Cl-, CaMg and color of soil. Multivariate analyses including detrended correspondence analysis (DCA) and redundancy analysis (RDA) were performed to analyze the collected data. The results showed that the vegetation distribution pattern was mainly related to conductivity and elevation. Separation of relevés into groups according to the first two axes of RDA provided four vegetation units, each one composed of several diagnostic species with highly significant fidelity value according to Fisher’s test. The theoretical maps produced by kriging revealed a close relationship between these vegetation units and conductivity.

Infections of bean plant and field soil are linked to region, root rot pathogen, and agro-ecosystem

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
B. Naseri ◽  
M. Gheitury ◽  
M. Veisi
Keyword(s):  
Root Rot ◽  
Multivariate Analyses ◽  
Control Method ◽  
Control Strategies ◽  
Fusarium Species ◽  
Macrophomina Phaseolina ◽  
Soil Variables ◽  
Plant Infection ◽  
Pathogen Prevalence ◽  
Soil Infestation

SummaryUnderstanding pathogen-agrosystem interaction is particularly essential when applying a control method to minimize pathogen prevalence prior to plant infection. To meet this requirement, frequency of major root rot pathogens isolated from bean root and seed, and their soil populations were examined in farmers’ fields. Multivariate analyses evidenced more frequent isolations of Fusarium solani and Rhizoctonia solani from root and seed compared to Macrophomina phaseolina and Fusarium oxysporum. Two Fusarium species had denser soil populations than R. solani and M. phaseolina. More frequent isolations of pathogens were detected in root and seed collected from Abhar and Khodabandeh compared to Kheirabad region. Agronomic and soil variables corresponded less closely to root infections compared to soil infestation and seed infections. Bean market class, herbicide application, and planting depth were linked to root, seed and soil infestations. Such information provides a basis for increased confidence in choosing appropriate control strategies for a pathogen and region in sustainable agriculture.

scholarly journals Plant communities of the Soutpansberg Arid Northern Bushveld

Koedoe ◽  
2009 ◽  
Vol 51 (1) ◽  
Author(s):  
Theo H.C. Mostert ◽  
George J. Bredenkamp ◽  
Rachel E. Mostert
Keyword(s):  
Plant Communities ◽  
Computer Software ◽  
Detrended Correspondence Analysis ◽  
Adansonia Digitata ◽  
Data Set ◽  
Themeda Triandra ◽  
Sociological Approach ◽  
Event Driven ◽  
Vegetation Maps ◽  
Single Data

The Soutpansberg Arid Northern Bushveld is one of eight major vegetation types (MVT) described for the Soutpansberg-Blouberg region. The plant communities of this MVT are described in detail. Main ecological drivers of the vegetation structure and species composition of these communities are discussed and some conservation recommendations are made. Phytosociological data from a subset of 72 Braun-Blanquet sample plots collected in the Soutpansberg Arid Northern Bushveld were classified using Two-way Indicator Species Analysis (TWINSPAN) and ordinated using a Detrended Correspondence Analysis (DECORANA). The resulting classification was further refined with table-sorting procedures based on the Braun-Blanquet floristic-sociological approach to vegetation classification using the computer software MEGATAB and JUICE. Eight plant communities were identified and described as Commiphora tenuipetiolata-Adansonia digitata short open woodland, Ledebouria ovatifolia-Commiphora mollis short bushland, Phyllanthus reticulatus-Acacia nigrescens short bushland, Tinnea rhodesiana-Combretum apiculatum short bushland, Dichrostachys cinerea subsp. africana-Spirostachys africana low thickets, Themeda triandra-Pterocarpus rotundifolius short closed grassland on steep basaltic slopes, Cyperus albostriatus-Syzygium cordatum sandveld wetlands, and Sesamothamnus lugardii-Catophractes alexandri tall sparse shrubland. These plant communities are event-driven ecosystems, predominantly infl uenced by frequent droughts, exposure to desiccation and unpredictable rainfall events. The complex topography of the Soutpansberg further contributes to the aridity of these ecosystems. The classifi cation and ordination analyses show similar groupings in the vegetation of the Soutpansberg Arid Mountain Bushveld. This confi rms the usefulness of complimentary analysis, using both classifi cation and ordination methods on a single data set in order to examine patterns and to search for group structure.Conservation implications: The results from this study will alter existing regional vegetation maps profoundly. The described plant communities of these arid event-driven ecosystems should be used as benchmark examples of the region’s primary vegetation. Conservation and management planning should be based on these vegetation units.

scholarly journals The vegetation types and management units of Goedverwacht farm in the mixed bushveld of the Northern Province, South Africa

Koedoe ◽  
1997 ◽  
Vol 40 (2) ◽  
Author(s):  
L. Breebaart ◽  
M. Deutschlander
Keyword(s):  
Plant Communities ◽  
Correspondence Analysis ◽  
Canonical Correspondence Analysis ◽  
Environmental Gradient ◽  
Detrended Correspondence Analysis ◽  
Northern Province ◽  
Computer Programme ◽  
Data Set ◽  
Management Units ◽  
Floristic Data

An analysis of the vegetation of Goedverwacht farm in the mixed bushveld of the Northern Province is presented. Releves were compiled in 33 stratified random sample plots. Eight distinct plant communities were identified by means ofBraun-Blanquet pro-cedures. Detrended correspondence analysis (DCA) was applied to the floristic data set using the computer programme DECORANA (Detrended Correspondence Analysis) to determine a probable environmental gradient and to facilitate in the identification of management units. The computer programme CANOCO (Canonical Correspondence Analysis) was used to apply canonical correspondence analysis (CCA) to the floristic data set. Two management units were determined by means of vegetation ordinations and soil data. A classification, description and ecological interpretation of the plant communities as well as a description of the management units are presented.

scholarly journals Mountain pastures of Qilian Shan: plant communities, grazing impact and degradation status (Gansu province, NW China)

Hacquetia ◽  
2016 ◽  
Vol 15 (2) ◽  
pp. 21-35 ◽  
Author(s):  
Alina Baranova ◽  
Udo Schickhoff ◽  
Shunli Wang ◽  
Ming Jin
Keyword(s):  
Plant Community ◽  
Plant Communities ◽  
Plant Cover ◽  
Management Strategies ◽  
Detrended Correspondence Analysis ◽  
Gansu Province ◽  
Grazing Impact ◽  
Vegetation Patterns ◽  
Pasture Management ◽  
Nw China

Abstract Environmental degradation of pasture areas in the Qilian Mountains (Gansu province, NW China) has increased in recent years. Soil erosion and loss of biodiversity caused by overgrazing is widespread. Changes in plant cover, however, have not been analysed so far. The aim of this paper is to identify plant communities and to detect grazing-induced changes in vegetation patterns. Quantitative and qualitative relevé data were collected for community classification and to analyse gradual changes in vegetation patterns along altitudinal and grazing gradients. Detrended correspondence analysis (DCA) was used to analyse variation in relationships between vegetation, environmental factors and differential grazing pressure. The results of the DCA showed apparent variation in plant communities along the grazing gradient. Two factors - altitude and exposure - had the strongest impact on plant community distribution. Comparing monitoring data for the most recent nine years, a trend of pasture deterioration, plant community successions and shift in dominant species becomes obvious. In order to increase grassland quality, sustainable pasture management strategies should be implemented.

scholarly journals Vegetation changes in boreo–nemoral forest stands depending on soil factors and past land use during an 80 year period of no human impact

2016 ◽  
Vol 46 (3) ◽  
pp. 376-386 ◽  
Author(s):  
Ilze Kokarēviča ◽  
Guntis Brūmelis ◽  
Raimonds Kasparinskis ◽  
Arta Rolava ◽  
Oļģerts Nikodemus ◽  
...  
Keyword(s):  
Land Use ◽  
Species Composition ◽  
Plant Communities ◽  
Agricultural Land ◽  
Deciduous Forest ◽  
Tree Canopy ◽  
Temperate Deciduous Forest ◽  
Soil Factors ◽  
Nature Protection ◽  
Forest Zone

Information on the long-term changes in plant communities that occur without human interference is limited, due to insufficient studies where vegetation can be resurveyed. In 1912, a strict nature protection reserve, with non-intervention management, was established on Moricsala Island in Latvia, located in the boreo–nemoral forest zone. Prior to establishment of the nature reserve, part of the island area was used for agriculture. The island is now covered almost entirely by forest dominated by Quercus robur L. and Tilia cordata Mill. on sandy soils. Resurvey was conducted in 2011 in 17 plots in which tree layers and the understory vegetation had been described in 1930. The plots were classified into two groups based on tree species composition in 1930 to determine changes in species composition. Differences in understory and tree canopy composition between these groups persisted over the period between the studies, in relation to soil factors and past stand history. Considerable turnover of species occurred, with a decrease of species typical of open habitats and replacement by species typical of nemoral (temperate deciduous) forest plant communities. In the past, Q. robur had likely established in open habitats created by agricultural land use or past fire but is presently not regenerating in the understory.

Diversity of subalpine and alpine vegetation of the eastern part of the Nízke Tatry Mts in Slovakia: major types and environmental gradients

Biologia ◽  
2009 ◽  
Vol 64 (5) ◽  
Author(s):  
Lucia Sekulová ◽  
Michal Hájek
Keyword(s):  
Plant Communities ◽  
Environmental Gradients ◽  
Ecological Factors ◽  
Detrended Correspondence Analysis ◽  
Dwarf Shrub ◽  
Soil Reaction ◽  
Data Set ◽  
Entire Data ◽  
Second Gradient ◽  
One Year

AbstractChanges in composition and structure of alpine and subalpine plant communities in relation to ecological factors were analysed in the Nízke Tatry Mts, Slovakia. Species cover values of vascular and non-vascular plants in each vegetation plot were recorded on the nine-degree scale. A data set of 156 relevés of alpine and subalpine vegetation was sampled recently during one year in the eastern part of the Nízke Tatry National Park. The data set was analysed by cluster analysis and Detrended Correspondence Analysis. analyses were carried out on the entire data set, including the subset of short grassland and dwarf-shrub vegetation. Major gradients and clusters were ecologically interpreted using Ellenberg indicator values. In the entire data set, the major gradient in species composition was associated with nutrient availability and the second most important gradient with light. In the case of short grassland and dwarf-shrub vegetation, the gradients were different. The first one was associated with soil reaction and the second gradient was associated with moisture. Clusters proposed by numerical classification reproduced many traditional phytosociological associations, namely Seslerietum distichae, Sphagno capillifolii-Empetretum nigri, Junco trifidi-Callunetum vulgaris, Juncetum trifidi, Dryopterido dilatatae-Pinetum mugo, Luzuletum obscurae, Agrostio pyrenaiceae-Nardetum strictae, while some other associations were less clearly differentiated (communities of the alliances Calamagrostion villosae, Adenostylion alliariae, Trisetion fusci, Cratoneuro filicini-Calthion laetae or Salicion herbaceae). The next clusters included Vaccinium and Festuca supina dominated communities and artificial roadside grasslands sown 50 years ago. Bryophytes and lichens were highly represented among diagnostic species of particular associations. Distribution pattern of particular plant communities was strongly influenced by site position either on northern or southern slope of the mountains.

Soil structure interaction analysis: modeling the interface

2002 ◽  
Vol 39 (3) ◽  
pp. 620-628 ◽  
Author(s):  
Morched Zeghal ◽  
Tuncer B Edil
Keyword(s):  
Soil Structure ◽  
Interaction Analysis ◽  
Laboratory Data ◽  
Contact Problems ◽  
Constitutive Law ◽  
Shear Stresses ◽  
Grain Crushing ◽  
Wide Range ◽  
Close Relationship ◽  
Element Technique

The sand–structure interface, developed under monotonic loading, was modeled based on physical observations. The model takes into account the macroscopic conditions to yield a general constitutive law applicable to a wide range of contact problems and the microstructural considerations constitute the specialization of the general equations to a specific problem. The surface of slippage was idealized to be sinusoidal based on an intensive numerical simulation program that made use of the discrete element technique. The model incorporates the effect of grain crushing found to play a major role in the behavior of the interface. Analysis of laboratory data revealed a close relationship between grain crushing and the work dissipated plastically during shear. The proposed elastoplastic model, requiring a limited number of parameters, predicts the shear stresses for the modified direct shear test and reproduces the shaft resistance of the shaft–sand interface pullout tests in a satisfactory manner.Key words: sand-structure interface, microstructure, grain crushing, plastic work.

The patterning of plant communities and edaphic factors along a high arctic coastline: implications for succession

1994 ◽  
Vol 72 (8) ◽  
pp. 1095-1107 ◽  
Author(s):  
L. C. Bliss ◽  
W. G. Gold
Keyword(s):  
Plant Communities ◽  
High Arctic ◽  
Organic Soils ◽  
Similar Species ◽  
Edaphic Factors ◽  
Beach Ridges ◽  
Cushion Plant ◽  
Devon Island ◽  
Isostatic Rebound ◽  
Biological Development

Isostatic rebound and the periodic development of ice-push beach ridges have created topography suitable for development of biologically rich polar oases along the northeast coast of Devon Island, Canada. Distinct patterning of both plant communities and edaphic factors from coastal shoreline areas inland indicate primary succession with a directional species replacement At Rocky Point (emergent < 2000 BP) biological development along the shore is initiated by marine algae that are invaded by cyanobacteria. These organic mats are colonized by Puccinellia on the shoreline of these brackish lagoons. Where the topography grades upslope, via concave areas, the toposequence from Puccinellia proceeds through Dupontia → Carex → Salix hummocks → cushion plant–lichen communities. In drier, convex areas Puccinellia proceeds through rosette-herb hummocks → cushion plant–lichen communities as a toposequence. Reduced levels of salinity and of nitrogen fixation upslope (from the shore) along with increased depth of organic soils and ability of soils to hold more soil water appear important in the conversion of Puccinellia- to Dupontia- to Carex-dominated meadows. This is the major chronosequence at Rocky Point and it is these Carex meadows that occupy most of the wetlands of Truelove Lowland. The Salix hummocks and cushion plant–lichen communities of all drier habitats resemble communities of similar species composition on the beach ridges of the lowland. Key words: arctic Canada, succession, plant communities, soil factors, polar oasis.

Effect on yield and juice quality of sugarcane following rice

1987 ◽  
Vol 109 (3) ◽  
pp. 599-600 ◽  
Author(s):  
D. V. Yadav ◽  
R. D. Singh
Keyword(s):  
Adverse Effects ◽  
Soil Structure ◽  
Growth And Yield ◽  
Juice Quality ◽  
Soil Factors ◽  
Physical Conditions ◽  
Effect On Yield ◽  
Harmful Effects

Sugarcane is usually grown after paddy in tropical and subtropical India; this rotation is adopted when sugarcane is planted in October (autumn planting). Soil puddling is required for paddy, but puddling disturbs the soil structure and impedes development of roots beyond the puddled layer. Adverse effects on growth and yield of sugarcane are therefore expected, but contrary to such expectations, sustained or increased yields of cane after paddy have been observed (Alvarez & Snyder, 1984; Anon. 1984; Snyder el al. 1986). It appears that certain other soil factors overcome the harmful effects of adverse soil physical conditions. Therefore, the present study was undertaken to investigate such factors.

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