Available micronutrient contents of soils in Long-Term Fertilization Experiments in Hungary

The National Fertilization Long-Term Experiments were set up in 19671969 in different agroecological regions of Hungary. Research results are needed to determine the direct effects of fertilizers on various soil proper-ties (acidification, biological activity, organic matter content, nutrient accumulation, losses and amounts of essential and toxic micronutrients). The soils of the experimental plots contained different nutrient levels due to the annual repeated rates of NPK fertilizers. Soil samples were obtained from eight sites with similar treatments at 0 to 20-cm depth. Plant-available (0.1 M KCl + 0.05 M EDTA-extractable) contents of Mn, Zn, Mo, and B were determined. The objective was to determine the effects of long-term NPK fertilizer applications on available levels of Mn, Zn, Mo, and B in different regions. Results showed that increasing P fertilizer rates influenced the plant-available Mo content. Increasing fertilizer rates also decreased the available B content of some soils. No correlation or tendency between the NPK fertilization treatments and available Mn content of soils was found. Fertilization had no significant effect on the plant-available Zn content of soils.