Zbigniew Bochenek Katarzyna Dabrowskazielinska Andrzej Ciolkosz Stanislaw Drupka And Vijendra K Boken

Poland is situated in the Great European Plain between the Baltic Sea and the Carpathian and Sudety mountains. Its territory includes lowlands (91.3%), highlands (7.7%), and mountains (1%). Most of Poland's soils are light soils of podsolic origin, which are usually of poor quality. It is for this reason that only 25% of the agricultural land, which accounts for 60% of the total territory and engages about 12% of population, is used for producing wheat, barley, sugar beets, rape seed, and vegetables. Average yields of main crops in Poland are lower than in the majority of West European countries. But the higher harvest areas put Poland sixth in Europe in the production of wheat, second in the production of rye and potatoes, and fourth in the production of sugar beet. The variation in the production of these crops during 1990-2000 is shown in figure 13.1.

Private farms cover about 84% of the total agricultural land. About 55% of the farms have an individual area < 2 ha. Liquidation of state farms and substantial reduction in the number of cooperative and collective farms have impacted the size of individual farms and increased their importance in agricultural production and Polish export. Since 1980, the average area of individual farms increased from 6.5 to 7.8 ha.

Poland is located in the region where precipitation exceeds transpiration. But since the 1960s, annual rainfall has gradually decreased by about 70 mm (Slota et al., 1992). Due to the shortage of precipitation, high temperature fluctuations in the spring, and cool weather during summertime, yields of the main crops have decreased and drought frequency has increased, particularly during the last decade (figure 13.2).

Spatial Distribution of Droughts and Their Causes

Drought usually begins in western Poland, moves through the central part, and eventually reaches eastern side (between 51°N and 54°N), which is g 20 5

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1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 YEAR.

—*—Wheat -•-Rye —■—Potato — Sugar beet

Figure I3.I Production of the main crops in Poland.

Figure I3.I Production of the main crops in Poland.

highly susceptible to droughts. Regions located above 54°N are in the zone of Baltic Sea climate characterized by higher rainfall (600-700 mm) and hence are less prone to drought than the rest of Poland. The distribution of drought-prone areas is shown in figure 13.3.

Droughts occurred 19 times in Poland during 20th century (i.e., once every 4-5 years; Slota et al., 1992). These droughts can be linked to the processes of air circulation over Europe and the adjacent ocean. Thermal-humidity anomalies caused droughts in 1977, 1983, 1989, and 1992 (the year of the great European drought). In 1992, drought affected more than 90% of the land, and the total precipitation was 40-50% below normal. This severe drought was caused by translocation of very warm, dry tropical masses of air in the beginning of summer, which increased evapotranspiration and reduced precipitation, forming long dry spells. In addition, poor drainage, accelerated land development, and acid rains also contributed to occurrence of poor yields and agricultural droughts in Poland.

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