Weather conditions impacts on maize yields in the northern Croatia

Aim of this study was testing connection between maize yields and weather characteristics (precipitation and temperature regimes) under environmental conditions of Podravina region for the period 1971-1990 and 1996-2003. Grain yields of maize are mainly higher in the eastern part of Podravina region compared to its western part. For example, based on 20-year means (1971-1990), maize yield in the eastern positioned Osijek and Donji Miholjac municipalities (mean 5.95 t ha-1) were by 42% higher compared to remaining three tested municipalities (Virovitica, Koprivnica and Varazdin: mean 4.18 t ha-1). These yield differences have been resulted mainly by soil properties. Yield variations among years for the short period are mainly result of weather conditions, especially precipitation and temperature regime during growing season. Although is observed that water deficit and the higher air-temperatures during growing season is in connection with the lower yields of maize, this phenomenon is impossible to prove by available yields and weather data for the 1971-1990 period. However, the last decade period is characterized by the higher fluctuation of precipitation and temperature regimes during maize growing seasons and available data are mainly better examples for comparison. For example, by comparison two growing seasons (2000 and 2002, respectively), were found maize yields (means by four counties) of maize 3.93 and 6.15 t ha-1, respectively. Precipitation in the 4-month period May-August (means of five weather bureaus) was 104 and 307 mm, for 2000 and 2002, respectively.