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Zbigniew Kaczmarek, Piotr Gajewski, Andrzej Mocek, Wojciech Owczarzak and Bartłomiej Glina

Abstract

The paper presents the characteristics of selected physical, chemical, and water properties of four mineral arable soils characterized with heavy and very heavy texture. Soil samples from genetic horizons of black earths from areas near Kętrzyn, Gniew and Kujawy, and alluvial soils from Żuławy were used. The following properties were determined in the samples of undisturbed and disturbed structure: texture, particle density, bulk density, porosity, natural and hygroscopic moistures, maximal hygroscopic capacity, saturated hydraulic conductivity, potential of water bonding in soil, total and readily available water, total retention in the horizon of 0–50 cm, drainage porosity, content of organic carbon and total nitrogen Parent rocks of these soils were clays, silts and loams of various origin. High content of clay fraction strongly influenced the values of all the analyzed properties. All the examined soils had high content of organic carbon and total nitrogen and reaction close to neutral or alkaline. High content of mineral and organic colloids and, what follows, beneficial state of top horizons’ structure, determined – apart from heavy texture – low soil bulk density and high porosity. The investigated soils were characterized by high field water capacity and wide scopes of total and readily available water. The saturated hydraulic conductivity was low and characteristic to heavy mineral arable soils. The parameter which influenced the variability of analyzed parameters most was texture.

Open access

Katarzyna Maj-Zajezierska and Piotr Koszelnik

Abstract

The aim of the present study was to determine the level of contamination of the bottom sediments in the Rzeszow reservoir by the selected heavy metals Pb, Cd and Zn, and to identify the potential environmental risks of heavy metals content basing on available assessments and classification of bottom sediments. The Rzeszow reservoir is situated on the Wisłok River in the Podkarpackie Voivodeship, southeaster Poland, was constructed on 1974. Nowadays, as a result of silting, the reservoir reduced its surface and depth, which does not have a positive effect on the assumed functions it is to perform. The study was conducted in 2016. The samples of sediment were collected in five locations. Samples were taken twice: in June and in October. The following concentrations have been determined: cadmium - 0.01 ÷ 0.92 mg•kg–1, zinc - 54.39 ÷ 128 mg•kg–1, lead - 2.98 ÷ 25.42 mg•kg–1. The decline trend in the sediment is following: Zn > Pb > Cd. For the assessment of sediment contamination, following methods: aquatic sediment quality classification used by the Polish Geological Institute - I class, Regulation of the Minister of Environment of April 16 2002 on the types and concentrations of substances contaminating the excavated material – unpolluted and LAW sediment classification – Pb - I/I-II, Cd - I/I-II/II and Zn - I/I-II. The obtained results were compared with the results obtained by the other authors in earlier years, which led to the estimated changes in the concentration of the tested metals.

Open access

Al-Amin D. Bello, Noor B. Hashim and Ridza M. Haniffah

Abstract

Abundant rainfall areas promote sediment yield at both sub-watershed and watershed scale due to soil erosion and increase siltation of river channel, but it can be curtailed through planned urbanization. The urbanization of Skudai watershed is analysed from historical and future perspective. A GIS-based model (Hydrological Simulation Programme-FORTRAN-HSPF) is used to modelled sediment flow using basin-wide simulation, and the output result is utilized in evaluating sediment yield reduction due to increased urbanization by swapping multiple temporal land-use of decadent time-steps. The analysis indicates that sediment yield reduces with increase urban built-up and decrease forest and agricultural land. An estimated 12 400 tons of sediment will be reduced for every 27% increase in built-up areas under high rainfall condition and 1 490 tons at low rainfall. The sensitivity analysis of land-use classes shows that built-up, forest and barren are more sensitive to sediment yield reduction compared to wetland and agricultural land at both high and low rainfall. The result of the study suggests that increased urbanization reduced sediment yield in proportion to the rainfall condition and can be used as an alternative approach for soil conservation at watershed scale independent of climate condition.

Open access

Vishwas Kale, Hema Achyuthan, Manoj Jaiswal and Somasis Sengupta

Palaeoflood Records from Upper Kaveri River, Southern India: Evidence for Discrete Floods During Holocene

A record of six discrete middle Holocene floods has been established based on sedimentological and stratigraphical studies in the upper Kaveri catchment at Siddapur. The flood events are represented by six discrete, sharp-bounded, sand-silt couplets. Texturally and geochemically the suite of couplets is quite distinct from the overlying and underlying structureless fluvial deposits. Based on OSL ages the suite of couplets cover the Holocene from ~8 to ~2 ka. Such evidence is not present or reported from any other river originating in the Western Ghat in the Indian Peninsula. We argue that the six couplets represent short-term, high discharge events or flash floods. The initiation of this phase of flash floods broadly corresponds with the southward migration of ITCZ and a gradual decline in Indian summer monsoon precipitation starting at ~7.8 ka. Comparison of the elevation of the highest couplet with the high flood level (HFL) of the 1961 extraordinary flood on Kaveri demonstrates that the 20th century flood was higher than the mid-Holocene palaeofloods.

Open access

X. Y. Li, Q. Z. Liu, Y. Z. Wang, H. Y. Sun, C. Q. Bai and E. E. Lewis

Abstract

Long-term changes of soil nematode diversity and distribution patterns in replant peach orchard (RPO) and continuous-planting peach orchard (CPPO) were assessed to evaluate different effects on nematode community and function by RPO and CPPO, in relation to peach replant problem from the point of soil fauna. Observations were conducted on a silt loam soil, and soil sampling was performed four times through the growing season of peach trees in the period from 2006 to 2008 in Pinggu, Beijing. The result showed that RPO differed from CPPO by its higher abundance of plant feeding nematodes but lower abundance of bacterivore nematodes, as well as significantly higher values of plant parasite index but lower nematode biodiversity. Obviously, the absolute abundance of Paratylenchus in RPO was higher than that in CPPO, which could be a key factor for the peach replant problems from the part of soil nematode. Nematode function indices and weighted nematode fauna profile analysis were no significantly different in the two peach ecosystems, but they represented an indication of high disturbance, N-enriched, bacterial decomposition pathway.

Open access

Agnieszka Hejduk and Leszek Hejduk

Abstract

Variability of suspended sediment grain size distribution in winter floods. The work presents the results of research concern variability of suspended sediment grain size, transported during the winter floods in agricultural catchment, in the period of hydrological years 2012-2015. The information about grain size distribution from nine winter flood events were collected over the study period, which allowed to analyze the variability of suspended sediment particle size during the various events. Grain size of sediment was determined using a laser particle size analyzer Mastersizer Microplus from Malvern Instruments Ltd. Variability of individual particle size classes were observed in each flood. Sand fraction dominated in seven of nine measured events. There was no significant increase of suspended sediment size in relation to the maximum of discharge. It can be explain by a relatively low discharge of recorded events. The percentage of material classified as clay (<4 μm) ranged from 0.08 to 1.01%, silt-sized material (>4 and <63 μm) ranged between 9.31 and 67.17% and sand-size material (>63 μm) ranged from 32.01 to 90.61%. The relationship between the particle size and the discharge requires further studies. The diameter d10, d50 and d90 and a standard deviation were calculated for each flood. Mean values of d50 for individual flood ranged between 41.05 and 191.32 μm with average value of 99.01 μm and average standard deviation of 32.57.

Open access

Ramadan Shawky

Abstract

Shawky R., 2018: Effect of edaphic factors on vegetation zonation in some littoral and inland salt marshes of Egypt. - Botanica, 24(2): 202-210. The segregation of a few dominant plant species into distinctive zones is characteristic of salt marshes. Vegetation zonation was investigated in the littoral salt marshes (South Marsa Alam region) and the inland salt marshes (Wadi El-Natrun region) of Egypt. Twenty taxa belonging to 18 genera and 11 families were recorded and classified into two sets at the two studied sites and subdivided into four groups by TWINSPAN, according to a relevance value: group A) co-dominated by Juncus acutus and Juncus rigidus; B) - dominated by Aeluropus lagopoides; C, D) - Limonium axillare. The analysis of species diversity in the inland salt marshes as well as the Shannon and the Simpson indices showed the highest species richness compared to that in the littoral salt marshes. The soil of the inland salt marshes was characterized by high percentages of silt, clay, also the soluble anion SO4 -2was the highest. While the most effective factor in the littoral salt marshes was EC, sand fractions, moisture content, soluble cations as Na+, Ca+2, soluble anions as Cl-, organic matter and CaCO3. The proximity matrix between the two types of salt marshes indicated that they were different, except for the stands of Juncus rigidus, the elucidation distance was the smallest and they were similar together.

Open access

Tomasz Wanic, Jan Bodziarczyk, Michał Gąsiorek, Paweł Hawryło, Agnieszka Józefowska, Bartłomiej Kajdas, Ryszard Mazurek, Marta Szostak, Michał Usień, Piotr Wężyk, Paweł ZadrożNy, Karolina Zięba-Kulawik and Tomasz Zaleski

Abstract

The primary objective of this study was to characterise the edaphic conditions of forest areas in the Pieniny National Park (PNP), and to describe the dependencies between properties of forest soils and types of forest plant communities. The “Soil Trophic Index” (SIGg) for mountainous areas was applied. The evaluation of the trophism for 74 forest monitoring employed the soil trophic index for mountainous areas SIGg or SIGgo. Plant communities in the forest monitoring areas were classified according to the Braun-Blanquet’s phytosociological method. Soils of PNP present in the forest monitoring areas were mostly classified as eutrophic brown soils (72.9%), rendzinas (10.8%), brown rendzinas (5.41%), and rubble initial soils (5.41%). Pararendzinas, dystrophic brown soils, and gley soils were less common (total below 5.5%). In the forest monitoring areas of PNP, eutrophic soils predominate over mesotrophic soils. High SIGg index of the soils is caused by high values of acidity and nitrogen content. The Carpathian beech forest Dentario glandulosae-Fagetum and thermophilic beech forest Carici albae-Fagetum associations are characterised by high naturalness and compatibility of theoretical habitats. The soils of the Carpathian fir forest Dentario glandulosae-Fagetum abietetosum subcommunity is characterised by a higher share of silt and clay particles and lower acidity as compared to the Carpathian beech forest Dentario glandulosae-Fagetum typicum subcommunity. The soils of the forest monitoring areas in PNP stand out in terms of their fertility against forest soils in other mountainous areas in Poland.

Open access

Kinga Śnieg, Dariusz Błażejczak and Małgorzata Słowik

Abstract

The objective of the research was to construct an empirical model for prediction of a unit pressure indispensable for generation of a specific compaction of soil samples. Soil material in the form of loose mass was collected from the soil layer deposited in the depth from 35 to 40 cm and then its typical properties were determined (textural group, density of solid particles, humus content, reaction, plastic and liquid limits) and in order to compact it in Proctor apparatus and in the uniaxial compression test. Results of both tests were used for construction of regression models reflecting the course of the unit strength (Pρd) necessary to generate compaction (ρdj) equal to the dry bulk density obtained in Proctor apparatus (ρdp), in relation to the sample moisture (ρdm). Searching for relations was restricted to the scope of moisure between an optimal one acc. to Proctor and the soil plastic limit. It was stated that the pressure value dp made on the soil sample in the uniaxial compression test depends significantly on w s and ρdm, and for description of this relation the use of multiple regression is sufficient. It was found out that for model samples with a textural group of silt loam and loam, differences in dry bulk density obtained in Proctor apparatus are approximately up to 0.15 g⋅cm−3.

Open access

Waldemar Świdziński

References Arias A. (1970) A measure of earthquake intensity, [in:] R. J. Hansen (ed), Seismic Design for Nuclear Power Plants , The M.I.T. Press, 438–483. Boulanger R.W. and Idriss I. M. (2006) Liquefaction susceptibility criteria for silts and clays, J. Geotech. and Geoenvir. Engrg. , ASCE, 132 (11), 1413–1426. Dyvic R. and Madhus C. (1985) ‘Measurements of G max using bender elements, Civil Engrs Convention , Detroit, New York, American Society of Civil Engineers, 1985, 186–196. PIANC (2001) Seismic Design Guidelines for Port