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Zastosowanie modelu LandscapeDNDC do symulacji warunków wodnych gleby oraz plonu roślin uprawnych

Nyćkowiak J., Leśny J., Juszczak R., Olejnik J., Blecharczyk A., Haas E., Kiese R., Butterbach-Bahl K.

Rocznik Ochrona Środowiska

2013

Tom 15, cz. 2

1937--1951

The purpose of the work was to assess the results of simulation of soil water content (SWC) and the simulated crop yield quantity using a module LandscapeDNDC model which belongs to the family of DNDC models. The assessment was conducted on the outcome data gathered during the simulation carried out in the experimental plots of Agricultural Experimental Station in Brody (nearby Poznań, Poland) in the period of 28 March to 13 August 2012. The crops grown in the experimental fields were as follows: alfalfa, potatoes, winter wheat, rye and spring barley. Average daily content of water in the soil at the depth of 10 cm from 28 March to 13 August 2012 was 12.95 ± 0.52% (CI = 95%). This value was measured by the sensors installed in the automatic measurement site located 20–60 meters from individual experimental fields. This area in 2011/2012 was overgrown by low vegetation (monocotyledons and dicotyledons). Simulated average value of SWC for the experimental plots in the same period was 12.43 ± 0.85%. These results lead to a conclusion that the model correctly simulates water conditions of the soil. Simulations conducted in LandscapeDNDC brought the crop yield results which amounted from 64.4 to 116.1% of the specific actual crop yield. The crop yield quantity of spring barley was simulated most accurately, then the crops of alfalfa, winter wheat and potatoes. The measured quantity of winter rye crop yield (7.1 t ha-1) differs from national average quantity which was 2.4 t ha-1 in the years from 1999 to 2011. Such a big crop yield obtained in the experimental plot is rare in farming conditions, which results in the overestimation of the crop yield quantity by the model.

Influence of fluctuating surface temperature and velocity on unsteady MHD natural convection adjacent to a permeable surface immersed in porous medium with heat absorption

Chaudhary R. C., Jain P.

Journal of Technical Physics

2006

Vol. 47, no 4

239-254

The present study will focus on the combined effect of oscillating surface temperature and fluctuating surface velocity, under the action of uniform transverse magnetic field applied normally to the plane and internal heat absorption effect. The wall temperature is oscillating periodically in time about a non-zero constant mean temperature. The plate is permeable enabling possible fluid withdrawal. The nonlinear coupled partial differential equations governing the flow, representing the constitutive laws, are transformed into a system of ordinary differential equations by the perturbation technique. A parametric study of all the parameters involved is conducted and a representative set of numerical results concerning the velocity and temperature profiles, as well as the amplitude and phase of skin friction and Nusselt number, is illustrated graphically to show typical trends of the solutions.