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| Kobus, Pawel. |
| The paper is dedicated to the relationship of data aggregation level and yield variability. For that purpose yields of the major crop plants in Poland are analysed i.e.: winter wheat, triticale, rye, barley, oat, mixed cereals, rape and sugar beet. The research are based on data from Polish FADN from years 2004 – 2009. The samples’ size ranged from 531 to 2893, depending on the plant crop. In the paper six levels of data aggregation are examined, that is: farm, district, powiat1, voivodship, region and country. It was found out that the degree of yield variability reduction (observed with data aggregation) is crop specific. Nevertheless, the relationship between aggregation level and yield variability can be approximated by the same formula for all of the... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Yield risk; Aggregation level; Risk and Uncertainty. |
| Ano: 2011 |
URL: http://purl.umn.edu/114712 |
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| Kobus, Pawel. |
| The paper deals with the problem of modelling yield risk measures for major crop plants in Poland. Hence, in some cases the gamma distribution offers a better fit to the data than normal distribution, and in addition to linear models, generalized linear models were also used. The research was based on data from Polish FADN, with sample sizes ranging from 416 up to 2300, depending on the crop plant. It was found that models based on the farm level data, can explain on average 20% of variation coefficient unevenness. The most important variables were average yield, type of farming, arable area and land quality. The elimination of the average yield from the models reduced the average determination coefficient to about 9%. |
| Tipo: Presentation |
Palavras-chave: Production risk; Risk measures; Yield distribution; Risk and Uncertainty; Q10; C46. |
| Ano: 2012 |
URL: http://purl.umn.edu/122535 |
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