Mineral fertilization and liming impact on maize and wheat yield

Abstract

The soil analyses for the field trials started in the spring of 2003 at site Donji Miholjac in eastern Croatia. Two different soil types were chosen with distance less then 1 km: silty loam dystric luvisol and silty loam calcaric regosol (limey substrate was excavated for the melioration canals and redeposited as top soil layer in 1986). The dystric luvisol was very acid (pHKCl 4, 02) with 1, 66 % humus, 149 mg kg-1 P2O5 and 167 mg kg-1 K2O. The calcaric regosol was slightly alkaline (pHKCl 7, 14) with lower content of humus (1, 42 %), phosphorus (139 mg kg-1) and potassium (109 mg kg-1). In the spring of 2003 the dystric luvisol was limed with 0, 10 or 20 t ha-1 carbocalk (total Ca content 344 g kg-1 and P 4, 6 g kg-1) on soil depth 30 cm. In the autumn of 2003 and 2004 the both soils (dystric luvisol and calcaric regosol) were fertilized first for maize and in second year for wheat with three different nutrient amounts: no fertilization, standard mineral fertilization and doubled phosphorus fertilization. Dystric luvisol pH reaction was influenced by liming and fertilization and changes are measured one year after liming (before maize sawing) and two year after liming (after wheat harvest): 10 t ha-1 carbocalk raised pH value for approximately 1 pH unit and 20 t ha-1 for 2 pH units. Influence of mineral fertilization on soil pH is evident especially on liming treatment with 20 t ha-1 carbocalk. Liming without fertilization resulted in increased pHKCl from 4.02 to 6.33 and 6.22 after first and second year, respectively. At the same time, liming with standard fertilization raised pHKCl up to 5.83 and 5.98, and with doubled phosphorus fertilization reached pHKCl was 5.72 after first year and 5.81 after second year. Liming did not affect maize yield but did slightly increased wheat grain yield and phosphorus removal by wheat grain. Mineral fertilization influenced significantly on yield and phosphorus and calcium removal comparing to production without fertilization. Although doubled phosphorus fertilization increased wheat yield and nutrient removal, only significant increasing comparing to lower phosphorus fertilization was phosphorus removal by wheat straw. Wheat and maize grains removed much more phosphorus and less calcium than straws.