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Proctor method was used to measure the effect of organic matter content in two types of loess soils on their compactability and on the relation between penetration resistance, moisture content, and bulk density.Increased content of humus caused a decrease of compability of the investigated soils and a decrease of their penetration resistance in dependence to moisture content and bulk density.
Określenie cech morfologicznych strąków i nasion jest ważne ze względu na kryteria hodowlane, parametry mechaniczne oraz jakość rynkową. W pracy wykorzystano metody analizy obrazu do wyznaczenia powierzchni, obwodu i wydłużenia strąków i nasion łubinu. Badaniami objęto po dwie odmiany łubinu żółtego (Markiz, Parys) i wąskolistnego (Boruta, Sonet). Stwierdzono zróżnicowanie powierzchni oraz obwodu nasion i strąków zarówno pomiędzy łubinem żółtym a wąskolistnym, jak i w obrębie analizowanych odmian. Strąki i nasiona odmiany Parys charakteryzowały się większą powierzchnią i obwodem niż odmiany Markiz. Tak dużych różnic nie stwierdzono dla badanych odmian łubinu wąskolistnego. Powierzchnia była cechą, która bardziej różnicuje nasiona analizowanych odmian niż ich obwód i wydłużenie. W przypadku strąków natomiast - to wydłużenie w największym stopniu różnicowało analizowane odmiany.
The efficiency of a system based on porous tubes in maintaining soil water potential during water extraction by plants in growth chamber experiment was evaluated. The effect of porous tubes area, soil type and density on water flow through porous tubes as induced by various water potentials was evaluated. The rate of change of soil water potential in response to pressure change depends strongly on the area of ceramic tubes per soil volume. If rapid changes or precise control of soil water potential are needed, the area of ceramic tubes per soil volume should be large. Experiments in which porous tubes are used for maintaining water potential should reach a compromise between plant water demands and permissible disturbance caused by the presence of porous tubes in the soil environment.
Drought and heat stresses are important threat limitations to plant growth and sustainable agriculture worldwide. Our objective is to provide a review of plant responses and adaptations to drought and elevated temperature including roots, shoots, and final yield and management approaches for alleviating adverse effects of the stresses based mostly on recent literature. The sections of the paper deal with plant responses including root growth, transpiration, photosynthesis, water use efficiency, phenotypic flexibility, accumulation of compounds of low molecular mass (eg proline and gibberellins), and expression of some genes and proteins for increasing the tolerance to the abiotic stresses. Soil and crop management practices to alleviate negative effects of drought and heat stresses are also discussed. Investigations involving determination of plant assimilate partitioning, phenotypic plasticity, and identification of most stress-tolerant plant genotypes are essential for understanding the complexity of the responses and for future plant breeding. The adverse effects of drought and heat stress can be mitigated by soil management practices, crop establishment, and foliar application of growth regulators by maintaining an appropriate level of water in the leaves due to osmotic adjustment and stomatal performance.
The aim of the research was to analyse the impact of soil water potential on the concentration of aluminium and selected mineral nutrients in soil solution. Soil acidification is a natural process accelerated by agriculture, and one of the most important factors limiting crop production worldwide. Concentrations of aluminium and selected mineral nutrients in solutions obtained from soil at initial pH 4.2 and after liming at various soil water potential were measured in centrifuged soil solution. Our results showed a significant gradual increase in the concentration of Al and most of mineral nutrients (Ca, Mg and P) with decreasing soil water potential from −3.5 kPa to −0.205 MPa. The results are important in the evaluation and interpretation of plant response to aluminium toxicity when accompanied by changes in water availability.
Flooded organic soils are potentially important sources of greenhouse gases. The effect of soil temperature and moisture on the concentration of N2O and CO2 at two depths of organic soil flooded with two doses of purified wastewater was studied. Nitrous oxide concentrations at the 10-30 cm depth range were generally increased with an increase in soil moisture, showing dependence on the aeration status of soil. The maximum values of N2O concentrations were higher at the 50-100 than 10-30 cm depth range, but a similar pattern of increasing maximum values of N2O concentration with an increasing input of nitrogen in treatments at both depth ranges was observed. The maximum concentrations of carbon dioxide within the 50-100 cm depth range remained at a similar level in all treatments reaching 7.1-7.7%, which indicated weak relations with the input of water and nitrogen at this depth range. We conclude that the N2O and CO2 concentrations at 10-30 cm depths in the examined organic soil flooded with 600mm year-1 of purified wastewater exhibited a similar level as the concentrations in soil watered only by precipitation.
The physical characteristics of soil aggregates influence soil tilth, surface sealing, water infiltration and root growth. Soil management and compaction significantly affect these characteristics. The aim of this work was to determine the effects of tractor traffic across the slope on bulk density, water stability, tensile strength and sorptivity of aggregates from grass covered and cultivated sloping (18%) vineyard soils. The grass covered (G) treatment included periodical mowing and cutting back of herbage and cultivation (C) treatment consisting of autumn ploughing (18 cm) and spring and summer rotary hoeing in the vineyard inter-row zones (2.7 m). A crawler tractor (2.82 Mg) was used in the inter-row zones, moving across the slope for all tillage and chemical operations. Soil aggregates were taken from the inter-rut and the upper and lower rut areas (0-10 and 20-30 cm) in the inter-row zones and then air-dried. Bulk density and tensile strength were lowest in the inter-rut areas and highest in the lower crawler rut. Aggregate water stability was greater under the lower rut and sorptivity in the inter-rut area in comparison to the remaining inter-row areas. In comparable inter-row areas, water stability and sorptivity of soil aggregates were greater and lower under G than C, respectively. The differences in bulk density and tensile strength between G and C were not consistent and varied depending on the inter-row zone and depth.
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