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    Wyświetlanie 1-4 z 4
    Tytuł:
    Wplyw poziomu azotanow na emisje N20 z wybranych gleb w badaniach modelowych
    The influence of nitrates (V) level on N2O emission from selected soils in model investigations
    Autorzy:
    Stepniewska, Z
    Szmagara, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1401792.pdf
    Data publikacji:
    2000
    Wydawca:
    Polska Akademia Nauk. Instytut Agrofizyki PAN
    Tematy:
    gleby
    azotany
    poziom azotanow
    emisja gazow
    podtlenek azotu
    denitryfikacja
    badania modelowe
    soil
    nitrate
    nitrate level
    gas emission
    nitrous oxide
    denitrification
    model research
    Opis:
    Celem pracy było określenie wpływu poziomu azotanów w glebie na tempo denitryfikacji, mierzonej ubytkiem azotanów oraz ilością emitowanego podtlenku azotu. Do badań wybrano: glebę płową- Apglp.glp oraz dwie gleby brunatne - Bli i Bpgm-gc.sk, które wzbogacono dawkami azotanów do wartości odpowiadającej nawożeniu 100 i 200 kg N-NO3/ha. Emisja podtlenku azotu z gleby rozpoczęła się już w pierwszych trzech dniach, a jej wielkość maksymalna zależała nie tylko od dawki wprowadzonych azotanów (V), ale była przede wszystkim związana z cechami rodzajowymi gleby, które określają jej potencjalną zdolność do denitryfikacji i przy tym samym poziomie azotanów (V) była dwukrotnie większa w glebie brunatnej, w której zawartość węgla organicznego wynosiła 0,98% w porównaniu z glebą A o poziomie węgla organicznego równym 0,73%.
    The aim of this work was determination, influence on level of nitrate (V) in soil on denitrification rate, which was measured by amount of emitted nitrous oxide.For studies podzolic soil - Apglp.glp and two brown soils - Bli and Bpgm-gc.sk were selected. Native level of nitrate (V) in these soils was riched by addition of nitrates, up to the level of fertilization 100 and 200 kg N-NO3/ha. Emission of nitrous oxide from soil began before third day of incubation.Maximum emission depend not only on doses provided nitrates, but first of all was connected with soil properties.These properties determinate potential ability of soil to denitrification and was two times higher in soil B, with organic carbon level 0,98% than in soil A, which contained 0,73%C org. at the same level if nitrates.
    Źródło:
    Acta Agrophysica; 2000, 38; 209-219
    1234-4125
    Pojawia się w:
    Acta Agrophysica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wplyw zlokalizowanego stresu tlenowego w glebie na rozwoj korzeni i czesci nadziemnych kukurydzy [ modelowe badania rizotronowe ]
    Effect of localized soil oxygen stress on root and shoot development in maize ( a model rhizotrone study)
    Autorzy:
    Bennicelli, R P
    Powiązania:
    https://bibliotekanauki.pl/articles/1628361.pdf
    Data publikacji:
    1994
    Wydawca:
    Polska Akademia Nauk. Instytut Agrofizyki PAN
    Tematy:
    agrofizyka
    gleby
    kukurydza
    system korzeniowy
    wzrost roslin
    badania modelowe
    badania rizotronowe
    dynamika rozwoju
    powietrze glebowe
    aeracja
    stres tlenowy
    agrophysics
    soil
    maize
    root system
    plant growth
    model research
    development dynamics
    soil air
    aeration
    oxygen stress
    Opis:
    The aim of the study was to test the usefulness of split rhizotrone technique to investigate the effect of localized soil anoxia on root and shoot developement, using maize as a test plant. The experiment was performed in 6 split rhizotrons enabling differentiation of soil aeration status in each half of the rhizotron by blowing nitrogen or air through them. The rhizotrone consists of two parts (each 16.6 dm3 in volume) inclined with an angle 60°. Each part is constructed of 1 mm thick stainless steel plate with a glass inner wall for root observation and has dimensions 84 cm x 40.5 cm x 5.0 cm. The rhizotrons were filled in with a brown loess soil material (Eutric Camhisol) from Ap horizon (from Eli/6wka, near Lublin). Maize seedlings with the roots splitted between the rhizotrone halves (eukivars KLG 2210 and DEA) were used in the experiments. Until the stress period the soil moisture tension of 20-80 kPa provided good water and air conditions. At a stage of 8 leaves three treatments were applied for a period of 7 days; an oxic control (P/P), a localized anoxia with 50% of the roots in nitrogen treated part (P/A), and a complete anoxia (A/A) with gas nitrogen in both parts. During the stress period diurnal elongation rates of primary roots (by marking positions of the tips each day) as well as distribution of two indicators of soil oxygenation status with depth viz. of oxygen diffusion rate (ODR) and of redox potential (Eh) in soil were measured. Shoot elongation rates were monitored with a potentiometer attached to the youngest leaf. Microscopic photographs of cross- sections of the caps and of apical meristems of primary roots at 400 magnification were made to show the changes in their anatomy due to anoxia. Chemical analysis of the shoots was performed after the stress period. For each cultivar the experiment was repeated three times. The investigations performed allowed the following conclusions to be drown out: 1. The split rhizotrone was shown to be a useful technique to study behaviour of the primary maize roots under localized anoxia conditions. 2. The ODR and Eh distribution with depth showed deterioration of oxygenation status (drop of ODR from control values above 100 |µg m-2 s-1 to the level 30 µg m-2 s-1, decrease of Eh from control values above 550 mV to the level, 300 mV) due to replacement of the soil air with gaseous nitrogen. 3. Root elongation rates under anoxic conditions (both under complete - A/A, and localized - A/P anoxia) were on the level of about 50% of the controle (P/P) during first 4 days and decreased practically to zero by the end of the stress period. In turn, the oxic part of the rhizotrone combined with localized anoxia treatment of the same plant (P/A) exhibited compensation effect and was characterized by stimulation of the root elongation rate up to 80%. This effect was especially distinct after 2-5 days of the stress duration and then tended to decrease. 4Distribution of the root mass in depth under anoxic treatments was characterized by concentration of about 80% of the root mass within first 10 cm of the soil. 5.Microscopic photographs of the root tips showed, under anoxic conditions, shorter meristematic zone, smaller number of mitosis, beginning of aerenchyma formation and dying of the cells at a distance of 1 mm from the root cap. 6.The shoots responded to applying anoxia to both rhizotrone parts by 20% reduction of the growth rate. 7.Both root and shoot elongation rates were correlated also with the temperature. 8.Oxygen deficiency in soil resulted in an increase of exchangeable manganese, what was reflected by its increased concentration in the maize shoots.
    Źródło:
    Acta Agrophysica; 1994, 03; 3-72
    1234-4125
    Pojawia się w:
    Acta Agrophysica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wplyw geometrii probki na krzywa retencji wodnej gleby - badania modelowe
    Autorzy:
    Czachor, H
    Powiązania:
    https://bibliotekanauki.pl/articles/1401810.pdf
    Data publikacji:
    2000
    Wydawca:
    Polska Akademia Nauk. Instytut Agrofizyki PAN
    Tematy:
    gleby
    wilgotnosc gleby
    retencja wodna
    krzywa retencji wodnej
    sklad granulometryczny
    osrodki granularne
    sklad chemiczny
    potencjal wodny
    badania modelowe
    soil
    soil moisture
    water retention
    water retention curve
    granulometric composition
    granular medium
    chemical composition
    water potential
    model research
    Opis:
    Przedstawiono wyniki symulacji osuszania wirtualnego trójwymiarowego ośrodka granularnego. Wynika z nich, że zależność wilgotność - potencjał macierzysty gleby powinna zależeć od geometrii próbki rozumianej jako stosunek objętości do tej części powierzchni zewnętrznej przez którą próbka kontaktuje się z otoczeniem.
    The virtual 3D virtual grain medium was created and than divided on to a set of individual pores by means of the 3D tessellation procedure. Volumes of all pores and capillary pressure of all necks have been calculated. Simulation of drainage shows that moisture relenlion curve of virtual medium depends on soil sample geometry, i.e. the ratio of volume and surface connected with the atmosphere.
    Źródło:
    Acta Agrophysica; 2000, 38; 289-301
    1234-4125
    Pojawia się w:
    Acta Agrophysica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wplyw wlasciwosci mechanicznych ziarna pszenicy na rozklad obciazenia w zbiorniku
    Load distribution in a model bin as influenced by mechanical properties of wheat grain
    Autorzy:
    Horabik, J
    Powiązania:
    https://bibliotekanauki.pl/articles/1628324.pdf
    Data publikacji:
    1994
    Wydawca:
    Polska Akademia Nauk. Instytut Agrofizyki PAN
    Tematy:
    agrofizyka
    pszenica
    ziarno
    materialy sypkie
    wlasciwosci mechaniczne
    badania modelowe
    naprezenia
    obciazenia statyczne
    obciazenia dynamiczne
    rozklad obciazen
    zbiorniki cylindryczne
    anizotropia
    agrophysics
    wheat
    grain
    granular material
    mechanical property
    model research
    stress
    static load
    dynamic load
    load distribution
    cylindrical bin
    anisotropy
    Opis:
    To describe mechanical behaviour of a granular material it is indispensable to have parameters such as the coefficient of friction on a bin wall, the angle of internal friction and the bulk density and the k-value in Janssen's equation. The values of these parameters depend on many known and unknown factors. In the case of plant granular solids indisputable is the role of moisture content of grain, vertical pressure and sliding velocity. The purpose of this study was to determine the influence of mechanical properties of wheat grain on wall and bottom load distribution in a model grain bin. A series of tests involving eight filling methods, eccentric discharge from five different locations of a bin orifice and three bin wall surfaces were conducted on a laboratory scale cylindrical bin 0.61 m in diameter and 2.44 m high. The wall and flat floor of the bin were supported independently on three load cells so that load distributions could be isolated. Static and dynamic wall and bottom loads were found to be influenced by the filling method. Shower filling produced lower static load of the smooth wall as compared to central filling and higher static load of corrugated and rough walls. The experiments showed a significant influence of grain orientation on load distribution. Variable angle of internal friction within the Janssen differential element can explain the non-uniform load distribution obtained. The horizontal bending moments exerted on the wall and floor of the bin during eccentric discharge were found to decrease with an increase in the bin wall friction coefficient and were influenced significantly by the orifice eccentricity ratio, with the maximum moment occurring at ER equal to 0.667. The horizontal pressure distribution around the circumference of the bin wall depends on the height from the floor. Near the floor of the bin the horizontal pressure was larger on the side of the bin opposite the discharge orifice, while for locations higher above the floor, the horizontal pressure was larger on the side nearest the discharge orifice. As the ratio of the grain height to the bin diameter decreased below approximately 1 a change in the direction of the resultant friction force on the bin wall from a normal downward direction to an upward direction was observed. The change in direction of the resultant tangent force originates from the combination of the downward friction force of flowing grain and the upward friction force of the grain contained within the dead zone of the bin. Moisture content of grain influences its compressibility, friction against the bin wall, height of the dead zone and, in consequence, the upward movement of grains in the dead zone of the flat bottom bin during discharge.
    Źródło:
    Acta Agrophysica; 1994, 01; 71
    1234-4125
    Pojawia się w:
    Acta Agrophysica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-4 z 4

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