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In this study, the effect of arbuscular mycorrhizal fungus − AMF Rhizophagus intraradices inoculum (prior or with transplanting) to different pepper type (Capsicum annuum L.) cv. Arlequin F1 (long fruits) and Raiko F1 (bell pepper), on plant growth and physiological parameters in response to elevated soil P concentrations from organic greenhouse production with enhanced soil salinity, was investigated. To explain the physiological growth of mycorrhizal inoculated (M) and non-mycorrhizal inoculated (NM) plants, the parameters of fungal root length colonization, shoot concentration of P an N during growth, plant height, width of stem, yield, number of fruit per plant and also the quality parameters of fruits such as soluble solid content (SSC), fruit color, mineral profile, total soluble phenolics (TSP) and antioxidant activity (FRAP), were determined. This study showed that application of AMF in cv. Raiko cultivated in high P saline soil generally enhanced growth, fruit yield and number of fruits per plant when inoculated at planting time in the greenhouse. AM inoculated plants, regardless of the time of application in cv. Arlequin grown under the same conditions, did not have any significant differences in comparison with NM plants. Arbuscular mycorrhizal inoculation has great potential in enhancing the pepper growth and yield even in high soil P, however, because of the complexity and interaction of involved genotypes of pepper and AMF, the method and time of inoculation, the system of pepper production and environmental conditions, as well as assays have to be performed to verify positive effects.
The aim of the present research was to evaluate whether or not, and to what extent, exclusive mineral fertilisation affects the content of water-soluble ions determining the soil salinity. The soil was sampled from the arable layer of a multi-year field experiment carried out in 1974-2007. The research involved differentiated nitrogen fertilisation (factor I, n=3) and potassium fertilisation (factor II, n=4). The content of water-soluble ions was defined in water extract, in the soil to water ratio of 1:5; cations K+, Na+, Ca2+ were determined with the method of emission spectrometry and Mg2+ – with atomic absorption. Anions were analysed with the argentometric (Cl-) and nephelometric (SO4 2-) methods. In addition, electrolytic conductivity (R) was tested with the conductometric method, based on which the salt concentration in the solution (C) and the ionic strength (I) were calculated. The present results were statistically verified. The prolonged application of intensive nitrogen and potassium fertilisation (32 years) significantly differentiated the content of cations: K+, Na+, Ca2+ and Mg2+ as well as anions: Cl- and SO4 2- in soil solution. The contents of K+, Na+, Ca2+, Mg2+ in the soil solutions differed and fell within the range of (mean value) 0.136-0.507 (0.281) K+, 0.398-0.555 (0.472) Na+, 1-2.192 (1.350) Ca2+ and 0.211- 0.365 (0.272) Mg2+ mmol(+)⋅kg-1. The highest nitrogen dose significantly limited the concentration of SO4 2- in the soil solution, while the different doses of potassium did not result in such significant changes in the concentration of the above ions. The content of chlorine ions in the soil solution did not depend significantly on differentiated nitrogen and potassium fertilisation. No effect of the long-term mineral fertilisation on soil salinity was noted.
Spatial variation of soil salinity and sodicity is a typical characteristic of Songnen Plain grasslands in northeast China. Best management practices and grassland productivity improvement require further understanding of the relationships among the causal factors at field scale. A field soil survey for the interactions among salinity, microtopography, and vegetation was conducted on a 2.8 hectare saline sodic grassland at Da’an Sodic Land Experimental Station, Chinese Academy of Sciences, northeast China. Salinity of the soil decreases by depth increment with Na+ and HCO-3 as the dominant ions. Soil salinity and sodicity parameters measured include pH, electrical conductivity for 1 to 5 soil-water extracts (EC1:5), apparent electrical conductivity (ECa), sodium adsorption ratio, and exchangeable sodium percentage. Soil salinity is in an order of slope > mound > depression for microtopography and soil under S. corniculata community is in severe salinity, while there is no significant difference under P. australis-A. mongolica and P. australis communities. The water and salt regime in various microtopographical conditions also is discussed.
The effect of salinity on the activity of glutamine synthetase (GS EC 6.3.1.2.) and glutamate dehydrogenase (NAD(P)H-GDH EC 1.4.1.2-4) in shoots and roots of triticale seedlings was investigated. Stressed plants were cultured hydroponically on the 100 mM NaCl-enriched medium for 7 days and the physiological responses were measured. Apart from changes in morphology of plants, alterations in GS and NAD(P)H-GDH activity were reported. GS activity in roots of stressed plants grew slightly and in shoots it decreased by approx. 30% as compared to control plants. In shoots of both control and stressed plants two GS isoforms were detected: cytoplasmic (GS1) and chloroplastic (GS2). A drop in total GS activity in shoots of NaCl-treated plants was due to the drop in activity of GS2 isoform. The activity of GS1 grew slightly under saline stress. After staining of gels for GDH activity, no changes in isoforms were noted as compared with the control plants.
The effects of pH, electrical conductivity (EC), soluble cations (Na⁺, K⁺, Ca²⁺, Mg²⁺), and soluble anions (HCO₃⁻, Cl⁻, SO₄²⁻) on vegetation zonation in a salt-marsh community (Black Sea coast) were investigated on two localities at Black Sea Coast differing as to the altitude, community composition and zonation. Three zones (25–80 m wide) – lower, middle and upper were distinguished in each locality along 150 m transect and according to the vegetation types which were analysed with Braun-Blanquet method. The dominant species were following: Juncus acutus L., Salicornia prostrata Pall., Spergularia marina (L.) Gris, Hordeum geniculatum All., Plantago coronopus L. subsp. coronopus, Carex capitellata Boiss. and Bal, Artemisia santonicum L. and Juncus littoralis C. A. Mey. Soil samples were taken down to 50 cm. The results of soil analysis were evaluated by using Canonical Correspondence Analysis (CCA) from winter 1999 to autumn 2000. HCO₃⁻ concentration and inundation depth (2.22–21.44 cm) are the environmental variables that correlate the best with axis 1, whereas K⁺ concentration and inundation depth (2.22–21.44 cm) correlate the best with axis 2 during the study period. During winter 1999, HCO₃⁻ concentration showed the highest correlation with the canonical axis 1 and associated zone was H. geniculatum. In spring, summer and autumn 2000, inundation depth (3.44–19.11 cm) was the most prominent factor correlated with the first and second axes, respectively, with associated zone of C. capitellata. EC, Na⁺ and Cl⁻ concentrations were decreased during autumn in all vegetation zones except for C. capitellata and Artemisia santonicum zones in which Na⁺ and Cl⁻ concentrations and EC, respectively were increased during autumn. The C. capitellata (Cyperaceae) zone was located on the positive site of axis 1 during autumn 2000 and followed the gradient of inundation depth. S. prostrata, S. marina, H. geniculatum and P. coronopus subsp. coronopus seems to be adapted to the most saline soils, whereas C.capitellata indicates the wettest soils in the studied salt marsh. The Juncus littoralis zone followed the gradient of maximum salinity during autumn of the year 2000, but the zone was not related to the measured increase in soil salinity during winter, summer and spring. In both localities EC, Na⁺ and Cl⁻ concentrations were tended to decrease at upper zones. Inundation regime, K⁺ concentration, and HCO₃⁻ concentration are key factors affecting vegetation zonation in studied salt marshes.
W niniejszej pracy przedstawiono wyniki badań dotyczące wpływu związków ropopochodnych (olej napędowy i benzyna bezołowiowa) w glebie zasolonej NaCl na przebieg procesu nitryfikacji. Zastosowano zanieczyszczenie gleby NaCl w następujących stężeniach: 10, 100 i 1000 mmol·kg⁻¹. Kontrolę stanowiła gleba bez dodatku soli. Podwójny stres antropogeniczny otrzymano zanieczyszczając próbki z powyżej przygotowanych kombinacji olejem napędowym oraz benzyną bezołowiową w następujących dawkach: 0,1; 1 oraz 10% wag. Zasolenie gleby NaCl i jednoczesne zanieczyszczenie jej produktami ropopochodnymi wpływa niekorzystnie na przebieg procesu nitryfikacji w glebie, obniżając jego wartość. Wielkość tych zmian zależy od rodzaju i dawki wprowadzonego zanieczyszczenia. Benzyna bezołowiowa działa bardziej niekorzystnie na przebieg procesu nitryfikacji w glebie zasolonej szczególnie o zmniejszonej zawartości substancji organicznej, natomiast zaolejenie gleby zmniejsza toksyczne działanie NaCl.
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The island of Sri Lanka is free from serious natural hazards such as volcanic activity and earthquakes resulting from climatic extremes, but there are impacts of many natural disasters, such as landslides, floods and droughts, the intensity and frequency of which are increasing due to human interventions. Some areas of Sri Lanka are also periodically subject to cyclones that occur due to climatic conditions and geographical locations. Land degradation denotes all natural or anthropogenic processes that diminish or impair productivity of land. This occurs mainly through soil erosion, loss of organic matter and nutrients in the soil; salinization and large scale land degradation in Sri Lanka. Its manifestations today are heavy loss of soil, siltation in the water bodies, reservoirs and coastal waters, unplanned settlements, loss of arable land leading to declining productivity in agricultural lands and intensification of impacts of natural hazards such as flooding and landslides. Land degradation is a major problem in Eastern Coastal Area from Kalmunai MC, Karaitivu and Nintavur Divisional Secretariat Divisions (DSDs) of Ampara District. However, there is a considerable spatial heterogeneity exists within this area in terms of land use, topography, land management and socio-economic conditions. Therefore, land degradation assessment studies are very important for the sustainable development of the area. Considering the above background, this study was conducted with the objectives of developing a land degradation assessment model using a GIS based approach.
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