While vacationing in Poland this year, we might have had the impression that it was an exceptionally rainy summer. In August, for example, precipitation over most of our country exceeded multi-year norms by 110 to as much as 270 percent. One would think that after a fairly dry spring and a similar start to summer, the amount of water available to plants has increased significantly. Let’s analyze the 12. IUNG-PIB’s Climate Water Balance and let’s see if it was enough to guarantee abundant agricultural yields?
12. climate water balance of IUNG-PIB
TheInstitute of Cultivation, Fertilization and Soil Science-State Research Institute has developed a Climatic Water Balance for all 2477 Polish municipalities. Based on soil categories, he assessed the status of agricultural drought risk in each administrative unit.
The average KBW value for the period July 11-September 10 was -37mm. Counting over a six-decade period, the value decreased by 11 mm from the previous one. The implication is that the water deficit for crops is smaller than in the earlier reporting period, but does this mean that we have already said goodbye to the drought?
The least plant-available water was recorded in the eastern part of the Greater Poland Lake District, Kujawy, the northern part of Polesie Lubelskie, the Zelechow Upland, and the northeastern parts of Poland. In these regions, the water deficit ranged from -140 to -169 mm. The situation was not much better in the southern and eastern part of the Mazovian Lowlands, the eastern part of the Greater Poland Lakeland and Greater Poland Lowlands, the Chelmno-Dobrzyn Lakeland, the Lublin Polesie and the northeastern part of the country. There, the Climatic Water Balance took values from -120 to -139 mm. In the rest of the country, water shortages of 0 to -119 mm were found.
These data were the basis for determining the occurrence of agricultural drought in the country. It reduces yields by at least 20 percent. on a municipal scale relative to yields obtained under average multi-year weather conditions.
Drought – where and for which crops? Climate Water Balance the basis for analysis
The Climatic Water Balance report finds drought in the Wielkopolska, Mazowieckie, Podlaskie and Łódzkie provinces. It covered 4 types of crops: corn for silage and grain, potatoes and fruit bushes. Silage corn crops have been most affected by the drought. It occurred in as many as 15 municipalities, which was 3.55 points lower than in the previous reporting period. Drought across the country covered 0.02 percent. arable land, down 0.35 percentage points from the previous reporting period.
In addition, drought was reported in crops:
- potatoes – in 12 municipalities (on 0.01 percent of Poland’s arable land); this is 0.12 percentage points more than in the previous period under review;
- fruit bushes – in 12 municipalities (on 0.01 percent of the country’s arable land); this is down 1.01 percentage points from the previous reporting period;
- Corn for grain – in 7 municipalities (on 0.01 percent of the country’s arable land); this represents a decrease of 2.38 percentage points from the previous reporting period.
Evapotranspiration vs. water deficit
The process of water evaporation from plant cells and from the ground in cultivated areas changed dynamically throughout the growing season. The first and second Climate Water Balance reported evapotranspiration of 2.5 mm/day. In subsequent reports, the value gradually increased until it reached 4.2 mm/day in the seventh report. This caused a continuous increase in water shortages. The eighth report fortunately already showed a drop to 4.0 mm/day. The downward trend has continued and the Twelfth Report reports 3.6 mm of evapotranspiration per day. This made more and more water available to plants, especially in southeastern Poland and the northwest.
Drought in the 2023 growing season
This year’s spring has greeted us with high sunshine, high wind speeds and little precipitation. Such conditions have created a very large water deficit for crops across the country. This resulted in crop losses of at least 20 percent. relative to yields in earlier years, when the weather was normal.
During the growing season, from March 21 to September 10, 2023, twelve Climate Water Balance assessment reports were prepared. They found agricultural drought affecting crops, ground vegetables and fruit trees, among others. This year has not been kind to farmers or consumers of agricultural crops. Hopefully, next spring will bring more rain and allow for a better start to the 2024 growing season.