scholarly journals Plant communities and associations of root crops of the Kałuszyńska Upland

2012 ◽  
Vol 61 (2) ◽  
pp. 121-129
Author(s):  
Teresa Skrajna ◽  
Janina Skrzyczyńska

A phytosociological classification and the characteristics of weed communities developing in root crops of the Kałuszyńska Upland are given in this paper. The presence of three associations: <i>Digitarietum ischaemi</i>, <i>Echinochloo-Setarietum</i> and <i>Lamio-Veronicetum politae</i>, as well as of two communities: <i>Setaria pumila</i>-<i>Setaria viridis</i> and <i>Panico-Setarion</i> alliance, has been found. The differentiation in trophic and soil moisture conditions of habitats results in the floristic diversity of communities, divided into lower phytosociological units. Two variants have been distinguished within the association <i>Digitarietum ischaemi</i>, whereas <i>Echinochloo-Setarietum</i> has been divided into 2 subassociations and 6 variants.

2012 ◽  
Vol 60 (1) ◽  
pp. 191-205
Author(s):  
Zofia Rzymowska ◽  
Janina Skrzyczyńska

This present paper, focused on root crop communities of light soils, is a part of the wide range characteristics of segetal communities of the Podlaski Przełom Bugu (Podlasie Bug River Gorge) mesoregion. On the basis of 160 phytosociological relevés made according to the Braun-Blanquet method, phytocenoses representing the <i>Panico-Setarion</i> alliance were distinguished. Most often, patches of the association <i>Echinochloo-Setarietum</i> were recorded in the study area. Heterogeneous habitat conditions affect its floristic diversity. Two subassociations of the phytocenosis, divided according to the species composition into 9 lower syntaxa, were identified on light soils. The following subassociations were distinguished: <i>Echinochloo-Setarietum setarietosum glaucae</i> in a typical variant and a variant with <i>Juncus bufonius</i>, both with subvariants with <i>Digitaria ischaemum</i>, as well as a typical variant of <i>Echinochloo-Setarietum typicum</i>, a variant with <i>Juncus bufonius</i> and a subvariant with <i>Oxalis stricta</i> in the typical and wet variant. Another association found in root crops on light soils of the Podlaski Przełom Bugu mesoregion is <i>Digitarietum ischaemi</i>. Its patches were observed in cultivations on light, acidic, poor soils. The characteristic feature of this community is the occurrence of numerous acidophilous species. In habitat conditions typical for the Podlaski Przełom Bugu mesoregion, <i>Digitarietum ischaemi</i> is differentiated into the typical and wet variant. Quite frequent patches of the <i>Setaria pumila-Setaria viridis</i> community were noted in intermediate habitat conditions, between those characteristic for <i>Digitarietum ischaemi</i> and <i>Echinochloo-Setarietum</i>.


1977 ◽  
Vol 14 (4) ◽  
pp. 445-465 ◽  
Author(s):  
E. Karl Sauer ◽  
E. A. Wilson

Natural vegetation can be a useful indicator of terrain conditions and thus has significant geotechnical implications especially in identifying moisture, groundwater conditions, and strati-graphic changes. A pilot study was initiated to study physiographic, climatic, biotic, and compensating factors as they affect plant communities in the Langham area, near Saskatoon, Saskatchewan. The study area is located at the transition between the Dark Brown and Black Soil Zones, which are colour zones of the surface soil horizon as influenced by climate and vegetation. It is suggested that the findings at Langham can be extrapolated over a wide band across the province where the soil zones and geomorphic units are similar. It was found that trees or shrubs are more reliable indicators of soil moisture conditions than low-growing plants and that plant communities are better indicators than individual species. In some places, the recognition of changes in vegetation patterns could make a significant contribution to geotechnical projects. A direct correlation was found between the number of species occurring in a plant community and soil moisture conditions. Drier sites had fewer species.


1978 ◽  
Vol 1 (2) ◽  
pp. 142 ◽  
Author(s):  
GF Gifford

Infiltrometer studies were conducted within several plant communities near Alice Springs, Northern Territory. Plant commu- nities studied included mulga-perennial, mulga-shortgrass, savanna woodland, gilgai, flood-plain grassland, and scalded areas (no vegetation). Attempts were made to quantify the impact of surface crusting, antecedent soil moisture conditions, and time of year on infiltration rates and potential sediment yields. Results indicate that the infiltration process within certain plant communities is often complex, and hydrologic differences which occur both within and among the plant communities should be acknowledged. Sediment yields from a floodplain-grassland unit and a scald situation were about 2 and 5 times greater, respectively, than those from various mulga communities, woodland, or gilgai circumstances. With one exception, antecedent soil moisture had little influence on sediment yields. Removal of surface soil crusts significantly increased sediment yields, regardless of antecedent soil moisture conditions. The relationship between soil movement and loss and ecosystem stability needs to be established for most rangeland environments, but little has been done to satisfy this need.


HortScience ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 599E-600
Author(s):  
Regina P. Bracy ◽  
Richard L. Parish

Improved stand establishment of direct-seeded crops has usually involved seed treatment and/or seed covers. Planters have been evaluated for seed/plant spacing uniformity, singulation, furrow openers, and presswheel design; however, effects of presswheels and seed coverers on plant establishment have not been widely investigated. Five experiments were conducted in a fine sandy loam soil to determine effect of presswheels and seed coverers on emergence of direct-seeded cabbage and mustard. Seed were planted with Stanhay 870 seeder equipped with one of four presswheels and seed coverers. Presswheels included smooth, mesh, concave split, and flat split types. Seed coverers included standard drag, light drag, paired knives, and no coverer. Soil moisture at planting ranged from 8% to 19% in the top 5 cm of bed. Differences in plant counts taken 2 weeks after planting were minimal with any presswheel or seed coverer. Visual observation indicated the seed furrow was more completely closed with the knife coverer in high soil moisture conditions. All tests received at least 14 mm of precipitation within 6 days from planting, which may account for lack of differences in plant emergence.


2021 ◽  
Vol 256 ◽  
pp. 107086
Author(s):  
Pingzong Zhu ◽  
Guanghui Zhang ◽  
Hongxiao Wang ◽  
Baojun Zhang ◽  
Yingna Liu

2021 ◽  
Author(s):  
Nunziarita Palazzolo ◽  
David J. Peres ◽  
Enrico Creaco ◽  
Antonino Cancelliere

&lt;p&gt;Landslide triggering thresholds provide the rainfall conditions that are likely to trigger landslides, therefore their derivation is key for prediction purposes. Different variables can be considered for the identification of thresholds, which commonly are in the form of a power-law relationship linking rainfall event duration and intensity or cumulated event rainfall. The assessment of such rainfall thresholds generally neglects initial soil moisture conditions at each rainfall event, which are indeed a predisposing factor that can be crucial for the proper definition of the triggering scenario. Thus, more studies are needed to understand whether and the extent to which the integration of the initial soil moisture conditions with rainfall thresholds could improve the conventional precipitation-based approach. Although soil moisture data availability has hindered such type of studies, yet now this information is increasingly becoming available at the large scale, for instance as an output of meteorological reanalysis initiatives. In particular, in this study, we focus on the use of the ERA5-Land reanalysis soil moisture dataset. Climate reanalysis combines past observations with models in order to generate consistent time series and the ERA5-Land data actually provides the volume of water in soil layer at different depths and at global scale. Era5-Land project is, indeed, a global dataset at 9 km horizontal resolution in which atmospheric data are at an hourly scale from 1981 to present. Volumetric soil water data are available at four depths ranging from the surface level to 289 cm, namely 0-7 cm, 7-28 cm, 28-100 cm, and 100-289 cm. After collecting the rainfall and soil moisture data at the desired spatio-temporal resolution, together with the target data discriminating landslide and no-landslide events, we develop automatic triggering/non-triggering classifiers and test their performances via confusion matrix statistics. In particular, we compare the performances associated with the following set of precursors: a) event rainfall duration and depth (traditional approach), b) initial soil moisture at several soil depths, and c) event rainfall duration and depth and initial soil moisture at different depths. The approach is applied to the Oltrep&amp;#242; Pavese region (northern Italy), for which the historical observed landslides have been provided by the IFFI project (Italian landslides inventory). Results show that soil moisture may allow an improvement in the performances of the classifier, but that the quality of the landslide inventory is crucial.&lt;/p&gt;


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