The Institute of Soil Science and Plant Cultivation – State Research Institute, in accordance with the Act of the Minister of Agriculture and Rural Development, has developed the climatic water balance values for all 2477 Polish municipalities (gminas) and, based on soil categories, calculated the current risk of agricultural drought.
In the second reporting period, i.e. from April 1st to May 31st, 2021 the average value of Climatic Water Balance (CWB), which is the basis for assessing the risk of agricultural drought, was negative and equalled -22 mm. The average CWB value has increased by 3 mm in relation to the previous reporting period (March 21st – May 20th).
The highest water deficit, ranging from -90 to -129 mm, was recorded in the north-eastern part of the Szczecin Coastland and central part of the West Pomeranian Lake District. Slightly lower deficit was recorded in the southern part of the South Podlasie Lowland and in Western and Volhynian Polesie, where it ranged from -90 to -119 mm. In the rest of the country, water deficit was less severe, from -50 mm to -90 mm or in some places even excess of water was recorded.
Based on the current humidity conditions, IUNG-PIB states the occurrence of agricultural drought in the area of Poland.
Agricultural drought occurred in the Zachodniopomorskie voivodeship.
In the second reporting period, from April 1st to May 31st, 2021, agricultural drought occurred in spring cereals and was recorded in two municipalities in the Świdwin district, i.e. 0.08% of all municipalities in Poland. Detailed data on drought occurrence are presented in table 1.
Table 1. Agricultural drought in spring cereals
|No.||Voivodeship||Number of local districts||Number of local districts at risk||Share of local districts at risk [%]||Share of the area at risk [%]|
This year’s April was the coldest in the last 24 years. Temperatures were low across the country. In the vast area of central Poland, the temperatures recorded were around 6°C. In the north of Poland, in the Lesser Poland Upland, Roztocze, the Sudeten and the Carpathian Foothills it was even colder, from 5 to 6°C, or in places even 4-5°C. In the Sudeten and Carpathian Mountains, temperatures were the lowest and ranged between 1-4°C. This year’s April, in relation to the multiannual norm, was colder in the south-eastern part of the country by 1°C, in the eastern part by 1-2°C, in Central Poland by 2 to 3°C, and in the western regions even by 3-4°C.
In the first decade of May, the highest temperatures were recorded in the western, south-western, southern, and south-eastern regions of Poland, ranging from 9 to 10°C, and even from 10°C to more than 11.5°C in the Sandomierz Basin. In the vast area of the country temperatures ranged from 8 to 9°C. In the north of Poland it was colder, from 7 to 8°C.
In the second decade of the month, it was significantly warmer. In the western and north-western regions of the country temperature ranged from 12 to 13°C. The further to the east, the warmer it was: from 13 to 14.5°C. Definitely the warmest region in the second decade of May was Kuyavia, with temperatures between 14.5-16°C.
In the third decade of May, temperatures became lower again. The lowest temperatures were recorded in the Sudeten Foothills, from 8 to 10°C, and in the eastern part of the West and East Pomeranian Lake Districts, from 10 to 11°C. The highest temperatures, on the other hand, were recorded in the Lubusz Land and in the vast areas of south-eastern Poland, where they ranged from 12 to 13°C.
In April, in the south-eastern part of the country, high precipitation values were recorded, ranging from 60 to 120 mm (i.e. 140% of the multiannual norm). In Central Poland precipitation was also intense, although less than in the south-eastern part of the country, ranging from 30 to 60 mm and constituting 90-140% of the norm in this area. In the northern regions of Poland, precipitation values were the lowest, ranging from 20 to 30 mm and, in places, even below 20 mm. In these areas, precipitation constituted from 40 to more than 90% of the norm.
In May, precipitation was more diversified. The lowest precipitation values in the first decade of the month were recorded in the north-western and south-eastern regions of Poland, ranging from 10 to 30 mm. Significantly higher values, from 30 to even 80 mm, were recorded in the area extending from south-western to north-eastern parts of the country.
In the second decade of May, scarce precipitation was recorded in Western Polesie and in central part of the Greater Poland Lowland, ranging from below 5 to 10 mm. Higher values, ranging from 10 to 20 mm, were recorded in the vast area of Poland. Relatively high precipitation, from 20 to more than 50 mm, occurred in central Poland, in the area extending from Gdańsk, through Łódź, Warszawa, Częstochowa, Kielce, Kraków, to Tarnów and Rzeszów. Similar precipitation values were recorded in the Sudeten Foothills, the Sudetes, Western Beskids and the Carpathians.
In the third decade of May, precipitation values varied across the country. In the western regions precipitation was low, from below 5 to 15 mm, whilst in the eastern part of the country higher values were recorded, ranging from 15 to more than 50 mm.
IUNG-PIB states highly diversified values of water deficit in the period from April 1st to May 31st. The highest water deficit was recorded in the Zachodniopomorskie voivodeship, where agricultural drought conditions were stated, resulting in yield reduction in spring cereals by at least 20% at municipality (gmina) level, in relation to the yield obtained in average weather conditions. Whereas, in the south and south-western part of the country, water deficit is the lowest, and there is even an excessive amount of water in agricultural fields, which may also result in a significant yield reduction in cultivated crops.
Prof. dr hab. Wiesław Oleszek
Report prepared by: Dr hab. Andrzej Doroszewski, prof. IUNG-PIB, Dr hab. Rafał Pudełko, Dr Katarzyna Żyłowska, Dr Jan Jadczyszyn, Mgr Piotr Koza, Mgr Anna Jędrejek, Mgr Małgorzata Kozak, Adrian Matczuk