Winter wheat crop water consumption and its effect on yields in southern Romania, in the very dry 2019-2020 agricultural year

Researches on winter wheat in the south part of Romanian Plain during the dry years 2019 and 2020 have been focused on the crop water consumption issue in excessive conditions of air and soil drought. The wheat crop water consumption in the research sites (Calarasi and Teleorman counties), for the entire vegetation period, autumn – spring – summer, is between 1000 and 1050 m3 of water for each ton of wheat produced. Only in the spring-summer period, the wheat extracts a quantity of about 5960 m3 ha-1, i.e. 851 m3 t-1. The useful water reserve is normally located at about 1500 m3/ha-1, at a soil depth of 0-150 cm. In the spring of 2020, it has been below 400 m3 ha-1, so that at the beginning of May the soil moisture had almost reached the wilting coefficient (WC). Wheat plants have been able to survive the thermal and water shock of late spring - early summer, due to enhanced thermal alternation between air and soil. For a period of about 34 days, this alternation brought the plants 1-1.5 mm water, i.e. approximately 442 m3 ha-1, which allowed the prolongation of the plant’s agony until the rains of the second half of May. Yields have been, depending on the variety, between 1500 and 3000 kg ha-1, in average, covering only 60% of the crop costs. Other measures to save water in the soil have also been proposed in the paper.