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Bubenickova A.,Ustav Technology Potravin | Simeonovova J.,Ustav Technology Potravin | Kumbar V.,Mendel University in Brno | Juzl M.,Ustav Technology Potravin | Nedomova S.,Ustav Technology Potravin
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis | Year: 2011

Precise modeling of sorting, manipulation, and transport processes of potatoes are conditioned by exact knowledge of tubers shape geometrical characteristics. The paper presents and quantifies some mathematical descriptive characteristics of potatoes. Ten selected varieties of potato tubers were analyzed. The basic dimensions were used for calculation of geometric mean diameter and volume. The maximum/minimum values were in both cases found for the same variety, Karin and Vera respectively. Calculated sphericity ranged from 0.007732 to 0.009803 for Krasa and Marilyn. The contour profiles were calculated by use of descriptive function and satisfying correlation (r 2 up to 0.9972) between computed and measured values was achieved. Radius of curvature was determined and evaluated in several positions. No statistically significant dependences of differences in curvature radius on neither variety nor position was found.

Babianek P.,Ustav agrochemie | Vavrousova P.,Ustav Technology Potravin | Ryant P.,Ustav agrochemie | Hrivna L.,Ustav Technology Potravin | Cerkal R.,Mendel University in Brno
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis | Year: 2010

The objective of the three-year small-plot trial was to assess the effect of the weather of the year, forecrop, variety, form of sulphur (elementary and sulphate) and additional nitrogen fertilising on the yields and the content of N-substances of the malt barley varieties Jersey and Sebastian. The trial was carried out in 2006-2008 at the experimental site of the Mendel University of Agriculture and Forestry in Brno, the Žabčice locality. The Jersey and Sebastian varieties were grown after three different f orecrops - winter wheat with ploughed down straw, sugar beet with ploughed down tops and maize for grain with ploughed down straw. The fertilising treatments differed in the form of sulphur (elementary and sulphate) and date of the additional nitrogen fertilising. As the sulphate form we chose ammonium sulphate (40 kg.ha -1 N and 45.6 kg.ha-1 S) and the same amount was supplied in the form of elementary sulphur; nitrogen was in the form of urea. A dose of 30 kg.ha-1 of ammonium nitrate with limestone (ANL) was applied as additional nitrogen fertilising. The results show that the weather conditions of the respective years had an almost 94 % effect on yields. The very strong effect of the weather overshadowed the effect of the f orecrop (3.8 %); the effect of the variety was only half that of the f orecrop (1.8 %). The form of additionally applied sulphur and nitrogen during cultivation had a relatively little effect on the yields (0.2 %). The f orecrop affected the content of N-substances most of all (47.3 %). The quality of barley grain is markedly dependent on the course of the weather of the year (40.1 %); the effect of the variety on the content of N-substances was relatively low (1.6 %). Applications of various forms of sulphur had a small effect on the grain quality (0.01 %), while the effect on additional nitrogen fertilising on the content of N-substances was 8.5 %.

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