Long-term Changes of Vegetation Season in Context of Spring Barley Phenology in South Moravia

The paper deals with the active sum of daily average air temperature above 5, 10, and 15 °C, and with the length of the vegetation season which is given by values of the daily average values of air temperature exceeding the given threshold (5, 10, 15 °C). The average values of four long-term periods (1931–1960, 1961–1990, 2021–2050, and 2071–2100) were compared to one another. A gradual increase of all the above mentioned characteristics was found. The area of interest involves several localities in south Moravia (the Czech Republic). These fi ndings were confronted with a long-term (1931–2012) analysis of spring barley’s phenological phases and with the date of sowing and the beginning of harvest. A prolongation of the interval between sowing and harvest was found; this was probably caused by agronomy machinery advancement. A prolongation of the interval between sowing and emergence and between heading and harvest, and a shortening of the interval between emergence and heading was also proved. A trend analysis of spring barley phenophases during 1961–1990 did not prove almost any signifi cant changes, except for a 12-day delay of the beginning of the harvest day, which was probably caused by a more effective mechanization.