Microcosmic study of soil microarthropod and earthworm interaction in litter decomposition and nutrient turnover

A microcosm experiment was set up under laboratory conditions and verified under field conditions with the objective of investigating the interaction of soil microarthropods and earthworms in litter decomposition, nutrient release, and uptake by maize crop. The treatments included: soil alone (control), soil with leaf litter (Senna siamea leaves), soil with leaf litter and soil microarthropods, soil with leaf litter and earthworms (Hyperiodrilus africanus), and soil with litter and both of the soil faunal groups. After an 8-week incubation period, the amounts of litter decomposed and N, P, K, Ca, and Mg released followed the order: with microarthropods and earthworms > with earthworms > with microarthropods > no faunal addition. The presence of microarthropods and earthworms also increased the net level of mineral N in the incubated soil. The additive roles of soil microarthropods and earthworms were observed on decomposition and nutrient release. Such faunal interactions resulted in an increased N uptake by maize in the incubated soil. Despite their lower biomass, soil microarthropods contributed significantly to nutrient turnover in the presence of earthworms. This study emphasizes the need to quantify and devise ways of controlling and regulating the abundance and activities of soil fauna for effective nutrient cycling and, consequently, for better crop yields in low-input tropical agricultural ecosystems.