Communication report regarding the incidences of drought conditions in Poland

Year: 2018; period: 01 (21.III - 20.V)

The Institute of Soil Science and Plant Cultivation – State Research Institute, in accordance with an Act of the Minister of Agriculture and Rural Development has developed the climatic water balance values for all 2478 Polish local districts (gminas) and, on the basis of soil categories, calculated the current risk of agricultural drought for the following crops: winter and spring cereals, rape and turnip rape, sugar beet, fruit shrubs and trees, and strawberries.

In the first reporting period, i.e. from March 21st to May 20th 2018, IUNG-PIB stated no agricultural drought conditions in Poland.

The average of Climatic Water Balance values, which are the basis for assessing the risk of agricultural drought, was negative and equalled -69 mm. At present, there is no risk of agricultural drought in Poland. The lowest Climatic Water Balance values were recorded for the Masovian Lowland and ranged from -100 to -109 mm.

March was very cold this year in the majority of the areas. The lowest temperatures were recorded in north-eastern Poland (-3°C) and the highest in the south-western part of the country, ranging from 1 to 2°C. The 3rd decade of the month was similar: in the north-western part of Poland the temperature recorded was 0.5°C, while in the south-western part it exceeded 3.5°C. In the majority of the country air temperature was lower than the multiannual average (1971-2000) by 1 to more than 3°C.

April was warm, the temperatures ranged from 9 to more than 14°C. The highest temperatures were recorded in the south (above 14°C), and exceeded the multiannual norm by 6°C. The further to the north, the lower was the temperature: ranging from 8 to 11°C, however, it was still 2-3°C higher than the multiannual norm.

In the first decade of May thermal conditions varied. It was the warmest in the south-eastern part of the country, where the temperatures exceeded 17°C, and the coldest in the north-western regions, where the temperatures ranged from 13 to 14°C. In the second decade of the month the south-eastern regions were the coldest, with temperatures ranging from below 13°C to 14°C. The highest temperatures were recorded in the north, ranging from 15 to more than 16.5°C.

In March precipitation varied across the country. High precipitation, ranging from 40 to 60 mm (100-140% of the norm), occurred in the north-western and south-eastern parts of Poland. Low precipitation, from 10 to 30 mm occurred in the area from north-eastern to south-western part of the country and constituted 40-80% of the norm. In the 3rd decade of the month, the highest precipitation occurred in the region of Kujawy, Szczecińska Lowland and Greater Poland (20-30 mm). In the southern and north-eastern Poland precipitation ranged fr°m 5 to 10 mm. In the rest of the country it was 10-15 mm.

In April precipitation also varied. Particularly low precipitation (below 30 mm) was recorded in the Kraków-Częstochowa and Silesian Uplands. Low precipitation (10-20 mm) was also recorded in Lesser Poland and Masovian Lowlands and in Sandomierska Basin, where they constituted 20-40% of the multiannual norm. Only in the north and east precipitation was more intense, from 40 to 60 mm and constituted 100-140% of the norm.

In May precipitation varied as well. In the first decade of the month the highest precipitation was recorded in the southern regions of the country and in the northern part of the Pomeranian Lake District: from 20 to 40 mm. In the rest of the country it was very low, ranging from 5 (or even less) to 20 mm.

In the second decade of May precipitation was considerably more intense, particularly in the southern part of the country, ranging from 15 to more than 50 mm. The highest precipitation was recorded in the Kraków-Częstochowa Upland, the southern part of Greater Poland and Masovian Uplands, and in Sandomierska Basin. In the north-western regions of Poland precipitation was scarce, below 5 mm.

Autumn 2017 was characterized by excessive soil water content resulting from frequent and abundant precipitation. Excessive water content in many regions of the country created obstacles to carrying out the field work and sowing winter crops. In the regions where sowing was delayed, the crops were weakened due to insufficient growth and development of plants. Numerous instances of waterlogging on the fields prevented seed germination and reduced crop density. Abundant and frequent rainfalls interrupted also application of plant protection measures and fertilisation.

Problems connected with excessive water saturation occurred mainly on heavy soils, however, excessive amount and distribution of precipitation interrupted field works on other types of soils as well, especially in the sowing period. Even light soils considered as undemanding in cultivation have been affected by the rainfalls and instances of waterlogging.

Many plantations of winter crops and rape that farmers managed to sow despite unfavourable water conditions entered winter period as underdeveloped and insufficiently grown, which increased their vulnerability to frost - especially in the regions where there was no snow cover or it was too thin to protect the plants against low temperatures.

Due to unfavourable atmospheric conditions in autumn 2017, and severe frosts in winter, in many regions of the country winter crops were very weak at the beginning of spring. On the other hand, water shortage in April and early May might cause lower yield this year.

Moreover, it is worth mentioning that, besides air temperature and precipitation discussed above, the Drought Monitoring System also takes into account other parameters, such as insolation, relative air humidity and wind speed, which have a significant influence on evapotranspiration and create the Climatic Water Balance values.

Despite the considerable water shortages, IUNG-PIB states no risk of agricultural drought in the current reporting period. According to the current weather conditions, yield losses resulting from water deficiency at the level of gminas are lower than 20% in comparison to yield obtained in multiannual average weather conditions. When determining drought conditions, only water deficiency is taken into account, although other yield-forming factors also have a significant influence on yield production.

Report prepared by:

Dr hab. Andrzej Doroszewski, prof. nadzw.

Dr hab. Rafał Pudełko

Dr Katarzyna Żyłowska

Mgr Piotr Koza

Mgr Elżbieta Wróblewska