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 Polish municipalities (3,064 municipalities), and based on the soils categories have identified in those municipalities the current agricultural drought risk for the following crops: rape seed, turnip rape and  sugar beets.

In the thirteen reporting period, i.e. from July 21 to September 20, 2013, IUNG-PIB does not state a risk of agricultural drought in Poland.

The average value of climatic water balance (CWB), based on which defines the agricultural drought risk during the period from August 1 to September 30 this year, was -30 mm. This is the third consecutive sixty-day period in which the CWB in the country increased significantly. In the current sixty-day period compared to the situation from 10 days ago, the CWB increased about 37 mm. Such a large increase of CWB caused that the water shortage for the crops in Poland, again decreased significantly.

The lowest values of CWB in Poland occurred in the same territory as in the previous sixty-day period (in the south-eastern area of the country). However, the current values of the CWB compared to the previous period are higher by an average of 50-60 mm. The largest water deficit in the current sixty-day period occurred in the Chodelska valley, from -90 to -99 mm. However, in the Iłżeckie Foothills, Radom Plains, Kozienicka and Sandomierz Uplands, the CWB value ranged from -80 to -89 mm. Water deficit of similar size have also been reported in the Wielkopolska. Still water shortage was reported in south-eastern Poland, the deficit of water in the area ranged from -60 to -79 mm.

August this year was warm and very warm. The area with the highest air temperature in August was the Sandomierz Basin; highlands: the Silesian-Krakow and Malopolska; Plains: Wielkopolska and Mazowiecka (southern areas), the temperature ranged from 19 to 19.5°C. In most parts of the country, the air temperature ranged from 18 to 19°C. The north-eastern area of Poland was the coldest region of the country and the average air temperature ranged from 17 to 17.5°C. In relation to the long-term average, the air temperature was higher in south-eastern Poland by 1.5-2°C, on predominant areas within the country increased by 1-1.5°C with the exception of the northern regions, where it was higher by 0.5-1°C.

In the first ten days of September, the temperature in the country was very different. It was very warm in the west of the country from 15 to 16.5°C and in the eastern part of Poland it was much cooler, from 11.5 to 14°C. In the second ten days of this month, the air temperature varied very little over the country, ranging from 12 to 13°C. Only the north it was warmer, with temperatures ranging from 13 to 14°C, and southern regions of Poland were it was cooler and the air temperature was within 11 to 12°C. The third ten days of September was the coolest. In the North East part of the country the average air temperature was only 6 to 8°C, further to the north-west it was warmer, on the south Baltic Coastland temperatures were recorded at 10 to 11°C. In most parts of the country air temperatures ranged between 8 to 10°C.

Considering the whole of September, we find that there were no relatively variations in air temperature. The lowest temperature was recorded in north-eastern Poland, it was from 11 to 11.5°C, while in the west of the country it was warmer, with temperatures ranging from 12.5 to 13°C. In other areas of the country, the air temperature ranged from 11.5 to 12.5°C.

Relative to the previous sixty-day period, there was a reduction in evapotranspiration. The average evapotranspiration for the country was 156 mm and was lower by only 36 mm with respect to the previous sixty-day period. This is the fifth consecutive sixty-day period with smaller values of evapotranspiration. The highest evapotranspiration (similar like in the previous periods) occurred in the Malopolska Highlands, Śląska, Mazowiecka, Wielkopolska Lowlands and Lubuskie Lake District, and ranged from 160 to 180 mm. However, the lowest evapotranspiration (130-150 mm) was found in the northern parts of the country.

In August, the lowest rainfall from a few to 20 mm was recorded in south-eastern Poland. In addition, low values of precipitation were recorded in the north-western parts of the country from 30 to 40 mm. In the most of the territory, the precipitation ranged from 50 to 70 mm. The highest rainfall ranging from 90 to 100 mm and was recorded in the northern parts of Poland (coastal region of Koszalin).

In the first ten days of September, rainfall distribution was very similar to that of August. The lowest rainfalls from a few to 20 mm were recorded in the south-eastern and north-western parts of the country. However, the highest rainfall ranging from 40 to 45 mm was recorded (as in August) in the northern regions in the coastal region of Koszalin. In the second ten days of September, the lowest rainfall was in the north-western Poland, the precipitation ranged from a few to 30 mm. However, the area with the highest rainfall in the second decade of September was the north-eastern Poland, where there has been relatively high rainfall ranging from 70 to 150 mm. The third ten days of September was a period with very high rainfall. Mazowsze and Podlasie precipitation ranged from a few to 10 mm, in large areas of central Poland rainfall was not high and ranged from 10 to 15 mm. Only in the south parts of the country in the mountain areas, and on the Gdansk Coastland precipitation was slightly higher, ranging from 30 to 35 mm.

When considering the entire month the north-eastern Poland was characterised with very high rainfall. Precipitation in this part of the country ranged from 130 to as much as 220 mm. The lowest rainfall was recorded in the north-western part of Poland and Lublin region and Carpathian, which ranged from 50 to 60 mm.

In the four previous sixty-day periods, areas with the greatest water deficit were Lublin, Subcarpathian and eastern regions of the Malopolska Upland. The situation in currently sixty-day period it has not changed. In that territory, it continues with the largest water deficit, except that it is now much smaller.

This is the second consecutive period under consideration, which is considered favourable for crops in terms of moisture, because it was a period of relatively low water shortages, while there were areas of excess. Continued since the beginning of July and August, the water deficit caused a loss in yield in many crops, especially in the south-eastern region of the country. However, rainfall that occurred in September, significantly improved water relations of these areas and no longer have such a negative impact on the course of the growing season and yield losses, as was the case in previous sixty-day periods. Current conditions should be considered particularly advantageous for winter crops and for rapeseeds.