Decomposition rates and feeding activities of soil fauna in deciduous forest soils in relation to soil chemical parameters following liming and fertilization

Abstract

This study investigated the influence of liming and P/K fertilization on the feeding activities of soil fauna and leaf litter decomposition rates in deciduous forest soils. The parameters examined were correlated to soil chemical characteristics. In 1994, we established a field experiment with six plots in an oak-beech forest and added different amounts of dolomite, partly combined with P/K fertilization. Two years thereafter a bait-lamina test was used to examine the feeding activity of soil fauna and a minicontainer test to study beech-leaf decomposition. In 1996, the feeding activity in the Ah horizon was lower in the plots left untreated in 1994 than in the plots which had been fertilized in 1994. The highest feeding activity was found in the treatment with 6 t dolomite ha–1 plus P/K. In all plots, the feeding activity decreased with increasing soil depth. The decomposition rates varied from 0.49% to 0.78% week–1 in the period April–October 1996. In 1996, the plots treated with 6 t dolomite ha–1 had the highest decomposition rates and differed significantly from those treated with 9 t or 15 t dolomite ha–1. No significant differences were found between the untreated plots and those treated with 9 t or 15 t dolomite ha–1. These results were confirmed by those obtained in 1997. The C/N ratio of litter also decreased, mostly in the treatment with 6 t dolomite ha–1. Feeding activities in the Ah horizon correlated positively with pH and concentrations of mobile Ca, Mg, K, and negatively with concentrations of mobile Al and heavy metals. We concluded that an increased supply of mobile nutrients and a decrease in mobile Al and heavy metals in these forest soils, as well as a balanced ratio between macro- and micronutrients, led to increased biological activity.