Effects of precipitation and temperature regimes on maize (Zea mays L.) yields in Northwestern Croatia

Maize growing in Croatia is characterized by considerable yield variations among years. For example, during 1998-2007 annual yields of maize ranged from 3.93 t/ha to 6.92 t/ha. In general, the higher quantities and uniformly distributed precipitation coupled with lower air temperatures during the summer months were more favorable for maize as compared to lower precipitation and higher temperatures. The majority of maize acreage is located in the Pannonian region (eastern and northwestern Croatia) which occupies nearly 50% of the state territory and as low as 4% of maize cultivated area is situated in the remaining part of Croatia. This study provides an overview of maize yields and cultivated areas in seven counties of northwestern (NW) Croatia for the 3-year period 2005-2007, along with weather data (precipitation and air temperatures: the data of the Sisak, Bjelovar and Zagreb Weather Bureaus). The region of NW Croatia occupies about 27% of the state territory and accounts for 50% of maize harvested area. Annual maize yields during the three years ranged from 5.18 to 6.78 t/ha. The growing season of 2007 was unfavorable for maize cultivation mainly due to drought and high temperatures. For example, according to the data of the Sisak Weather Bureau, the amount of precipitation for the three-month period (June-August) was only 100 mm or 60% lower than the long-term mean (LTM: 1961-1990) and the air temperature was 2.7°C higher. During the same period of the remaining two years of study, precipitation was 26% (2005) and 34% (2006) higher than LTM. As a results of these favorable conditions, maize yields in NW Croatia were 30% (2005) and 25% (2006) higher than those during the unfavorable 2007 growing season (5.18 t/ha). Adequate soil management practices, especially fertilization and liming of acid soil, can alleviate consequences of drought and high temperature for maize yields.