Boris Đurđević

Liming of acid soils in Osijek-Baranja County.

The negative trend of soil degradation process increases with intensive agricultural production. Therefore, there is a need for soil conditioning like liming, humification, fertilization, etc. to improve soil quality. One of the major problems that occur on agricultural soils of Croatia is acidification. A downward trend of soil pH is mainly present in soils of poor structure with intensive agricultural production. In agricultural practice liming often needs to rely only on the pH value, without determining the hydrolytic acidity, CEC or soil texture. Due to the above mentioned facts, calculation of liming for Osijek-Baranja County was conducted with the help of ALRxp calculator, which takes CEC, soil pH in KCl, hydrolytic acidity, bulk density of soil, soil textural class and depth of the plow layer to 30 cm into account. Low soil pH values have a great influence on soil suitability for crops as well as on the deficit of calcium and magnesium. All of these lead to the degradation of soil structure, and can even lead to disturbances of plant nutrition in some production areas. On such soils, liming would be imperatively required, but with caution because an excessive intake of lime materials, especially without the necessary analysis, causes a decline in organic matter and reduces accessibility for plant uptake of microelements.

Phosphorus, calcium and magnesium status in maize genotypes grown on acid soil

The response of five maize inbred lines and their three commercial hybrids to acid soil with low nutrients availability were studied in a field trial over a three year period (2003 to 2005) in the east Croatia. Grain yield and P, Ca and Mg concentration in leaves were analysed. Highly significant effects of the both, year and genotype for all traits were determined. Grain yield of maize genotypes ranged from 5.11 t ha-1 in dry year to 7.39 t ha-1 in more favourable year. Regardless of low soil P content, an adequate P status (3.17 g kg-1) in maize were found, while lower Ca (5.62 g kg-1) and Mg (2.36 g kg-1) mean concentrations in leaves are consequences of their low level in soil. However, considerable differences in P, and especially Ca and Mg status were found among parental lines, what was reflected on their progeny. The results indicated that origin of inbred line may have an important role for nutrient content inheritance.