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vol. 6, nr. 2 (2005)
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The effect of droughts on oats yielding in the Central-Eastern Poland
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Elżbieta Radzka1, Józef Starczewski2, Grzegorz Koc1
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1 Departament of Meteorology and Land Melioration, University of Podlasie |
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2 Departament of Soil Cultivation, University of Podlasie |
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vol. 6 (2005), nr. 2,
pp. 497-503
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abstract:
Droughts can be defined as atmospheric phenomena which bring about the highest losses in plant production. As a result of this, they are an important economic, social and environmental problem. Meteorological data from the years 1968-1997 come from the Institute of Meteorology and Water Management in Warsaw. The atmospheric droughts were determined by means of three methods. The oats yields from the years 1968-1997, coming from the publications by the Central Statistical Office, constituted the second set of data. The relations between oats yielding and the droughts, determined by means of the selected methods, were defined on the basis of the values of coefficients of linear correlation whose significance was checked at the significance level of 0.05 and 0.01. The statistical calculations that followed were based on the multiple regression method according to the model: Y = b0 = b1x1 + b2x2 + …+ bnxn, where: Y – dependent variable (yield); X1, X2, ..., Xn, – explanatory variables; b0 – free term; b1, b2, ..., bn –regression coefficients which say what change in the dependent variable (Y) will follow the unit change in the independent variable, when the remaining values are fixed. Regression equations were calculated applying the step regression procedure. The values of Sielianinow’s hydrothermal coefficients and the moisture indices in April were significant or highly significant at most stations and, additionally, they negatively correlated with the oats yield. In contrast, the droughts occurring in June significantly or highly significantly reduced the yielding of the examined crop plant, irrespective of the method applied. The variability of oats yielding was in 24% (Sobieszyn, Włodawa) to 55% (Ostrołęka) conditioned by the values of the atmospheric moisture index.
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keywords:
drought, yield, correlation, regression
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original in:
Polish
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