Impact of the projected climate change on soybean water needs in the Kuyavia region in Poland

According to the SRES A1B climate change scenario, by the end of the 21st century temperature in Poland will increase by 2–4°C, no increase in precipitation totals is predicted. This will rise crop irrigation needs and necessity to develop irrigation systems. Due to increase in temperature and needs of sustainable agriculture development some changes in crop growing structure will occur. An increase interest in high protein crops cultivation has been noted last years and further extension of these acreage is foreseen. Identifying the future water needs of these plants is crucial for planning and implementing sustainable agricultural production. In the study, the impact of projected air temperaturę changes on soybean water needs, one of the most valuable high-protein crops, in 2021-2050 in the Kuyavia region in Poland was analysed. The calculations based on meteorological data collected in 1981-2010 were considered as the reference period. Potential evapotranspiration was adopted as a measure of crop water requirements. The potential evapotranspiration was estimated using the Penman–Monteith method and crop coefficient. Based on these estimations, it was found that in the forecast years the soybean water needs will increase by 5% in the growing period (from 21 April to 10 September), and by 8% in June-August. The highest monthly soybean water needs increase (by 15%) may occur in August. The predicted climate changes and the increase in the arable crops water requirements, may contribute to an increase in the irrigated area in the Kuyavia region and necessity of rational management of water resources.