ADMS

The Institute of Soil Science and Plant Cultivation – State Research Institute, in accordance with an Act from the Minister of Agriculture and Rural Development has developed the climatic water balance for all 2478 Polish local districts and, on the basis of soil categories, calculated the current risk of agricultural drought for the following crops: winter and spring cereals, grain maize and maize for silage, potato, sugar beet, hops, tobacco, ground vegetables, fruit shrubs and trees, strawberries and legumes.

In the seventh reporting period, i.e. from June 1 to July 31, IUNG-PIB stated no risk of agricultural drought conditions in Poland. The Climatic Water Balance values, which are the basis for assessing the risk of agricultural drought, are negative for the majority of areas. However, for the aforementioned crops the values are higher than critical.

In the seventh reporting period the lowest Climatic Water Balance values have been recorded in the south-eastern part of Lubelska Upland (Roztocze), south-eastern part of Mazowiecka Lowland, in Kujawskie Lake District and in the north-eastern part of Małopolska Upland. At present, the lowest Climatic Water Balance values in these areas range from -120 to -159 mm.

In the current sixty-day period the Climatic Water Balance values in Poland have increased, on average, by 17 mm in comparison to the previous reporting period.

In June the lowest temperature, about 15°C, was recorded in the first decade of the month in the vast area of eastern Poland. The highest temperature was recorded in the west and north-west of Poland (ranging from 17 to 18.5°C). In the following decades the temperature has risen in the whole country and, on average, it exceeded 18.5°C. The lowest temperature, 14°C, was recorded in the north of the country in the second decade and the highest temperature, 22.5°C, in the south-eastern part of Poland in the third decade. June was very warm this year. In the vast majority of the country the temperature exceeded the multiannual average by 2-3°C.

In the first decade of July slight fluctuations in air temperature occurred. In the vast area of northern Poland the temperatures ranged from 16 to 17.5°C. In central and southern Poland the temperature ranged from 17.5 to 18.5°C. The second decade of July, in comparison to the previous one, was characterised by slightly higher variations in air temperature. Temperature exceeding 19°C was recorded in the area between Silesian Lowland and Oleśnicka Plain, in Roztocze and in Karpackie Foreland. In the central part of Poland, from Lubuskie Lake District, through Wielkopolskie, Kujawskie and Dobrzyńskie Lake Districts, Warszawska Basin, Mazowiecka Lowland and Południowopodlaska Lowland, as far as to Lubelska Upland temperature ranged from 18 to 19°C. In the north-western and north-eastern parts of Poland the temperature has slightly risen by 0.5°C. In Małopolska Upland it was lower and ranged from 17.5 to 18°C. Even lower was the temperature in Krakowsko-Częstochowska Upland (17-17.5°C). Taking into account the temperature, the second and third decades of July were very similar. The lowest temperature, below 18.5°C, was recorded in Pomorskie Lake District. In Mazurskie Lake District and Bełchatowska Upland it was slightly warmer, from 19.5°C to 20.5°C. In Wielkopolskie Lake District, Lubelska Upland and Małopolska Upland temperature ranged from 20°C to 21.5°C. High temperature, from 21°C to 21.5°C was recorded in Silesian Lowland and Sandomierska Basin. The highest temperature, 21.5°C, was recorded in Sudeckie Foreland, in southern parts of Mazowiecka Lowland and in Przemyskie Foothills.

The precipitation in June widely varied across the country. Relatively high precipitation occurred in the north-west of Poland and in the area between the Silesian and Małopolska Uplands, Mazowiecka Lowland, as far as to Mazurskie Lake District and ranged from 20 to 60 mm (40-80% of the multiannual average) and here and there from 60 to 100 mm (80-120% of the norm). Relatively low and very low precipitation, on the other hand, was recorded in the rest of the country and ranged from 5 to 20 mm (the lowest precipitation being recorded in the area of south-eastern Poland - not exceeding 10mm - and in the area of north-western part of the country). Such great variations in the amount of precipitation throughout the country resulted from the stormy character of rainfalls, which is why the areas with very high precipitation occurred right next to the low precipitation regions.

The first decade of July was characterised by very high precipitation, ranging from 40 to more than 100 mm in the north of Poland. In the north-east of the country it was slightly lower, from 40 to 60 mm. In the vast majority of the country precipitation ranged from 10 to 40 mm.

In the second decade of July precipitation in Poland was more diversified in comparison to the previous decade, due to its stormy character. The heaviest rainfalls were recorded in three main areas. In the first one, from Karkonosze, through Trzebnickie Hills, Gnieźnieńskie, Krajeńskie and Bytowskie Lake Districts, to Kaszubskie Lake District, precipitation ranged from 100 to more than 120 mm. In the second, from Głubczycki Plateau, through Silesian Upland, Krakowsko- Częstochowska Upland, Bełchatowska Upland, Łomżyńskie Interfluve, to Białostocka Upland, it ranged from 60 to more than 120 mm. In the third, in the east of Lubelska Upland and south-east of Podkarpackie Voivodship, precipitation was lower than in the remaining two and ranged from 40 mm to 80mm (the area of Roztocze). The lowest precipitation, not exceeding 20 mm, was recorded in Kielecka Upland, near the Świętokrzyskie Mountains. In the remaining part of the country precipitation ranged from 20 to 40 mm.

In the third decade of July the area with relatively intense rainfalls extended from Silesian Upland, Małopolska Upland to Lubelska Upland, where precipitation ranged from 20 to 80 mm. The highest precipitation, above 120 mm (140% of the multiannual average) was recorded in Krakowsko-Częstochowska Upland and in the north of Wielickie Foothills. In the central part of Mazurskie Lake District and in the eastern part of Pomorskie Lake District precipitation ranged from 40 to 80 mm (60-100% of the norm). The lowest precipitation, below 10 mm, occurred in Roztocze and in Podkarpacie. In the rest of the country it ranged from 10 to 40 mm.

Water deficiency still occurs in the whole country. In May and June it had particularly adversely affected the growing crops, resulting in yield reduction – the longer the period of water deficiency, the higher being the yield loss. The critical values of Climatic Water Balance for the particular crops and soils entail yield reduction in local districts by 20% in comparison to the yield obtained in average multiannual weather conditions. It often occurs that Climatic Water Balance values approximate critical levels in particular local districts, however, do not reach them, which means that average yield losses will not exceed 20%. Thanks to heavy rainfall in July, the water deficiency became less serious, especially in the areas where the water resources levels were the lowest. Due to the fact, that water deficiency levels are relatively low, there are currently no areas in risk of agricultural drought in Poland.

It has to be noted, however, that higher humidity will not significantly increase the yield of crops already affected by agricultural drought, and it still will be 20% lower in comparison to the yield obtained in average multiannual weather conditions.

Report prepared by:

Dr hab. Andrzej Doroszewski, prof. nadzw.

Dr hab. Rafał Pudełko

Dr Katarzyna Żyłowska

Mgr Piotr Koza

Mgr Elżbieta Wróblewska