Wheat and Maize Yield Variations in the Brod-Posavina Area

In general, wheat and maize yields in the Brod-Posavina County (BPC) were about 15% lower (10-year means 1981–1990) in comparison with their yields in the region. Wheat yield variations in the region among the years were higher in comparison with maize yield. For example, the highest yield of wheat and maize were higher than the lowest yield for 61% and 34%, respectively. Analogic comparison for Slav. Brod and N. Gradiska municipalities were 78% and 41% (wheat), as well as 41% and 24% (maize), respectively. In the last 8-year period, mean wheat yields in the region were for 17% lower and maize yield for 4% higher in comparison with mean yields of 80ies. These differences in level of BPC were 10% lower and 12% higher, for wheat and maize, respectively. We presume that low or absence effects of tile drainage because of their inadequate servicing could be expalantion for wheat yield decreasing. The lower yields of wheat are mainly in connection with oversupplies of water. However, low maize yields are in connection with water shortage and the higher air-temperatures. Low supplies of P and K are additional factors of low yields of field crops in the hydromorhic soils of the BPC.