Effects of soil microarthropods on nutrient release of decomposing litter with contrasting chemical composition

Abstract

An experiment was set up at the International Institute of Tropical Agriculture, Ibadan, to study the effects of litter quality on the role of soil microarthropods in litter decomposition and nutrient release. Leaf litters from Dactyladenia bateri, Senna siamea, Leucaena leucocephala, Cajanus cajan, Centrosema pubescens and Pueraria phaseoloides varying in biochemical and nutrient composition were tested using the litterbag method. Litterbags with 0.08 mm mesh-size were used to exclude microarthropods while litterbags with 0.5 mm mesh-size were used to include microarthropods but exclude macrofauna. Litterbags were surface-placed in soil under maize crop. The concentrations of the macronutrients (N, P, K, Ca and Mg) in remaining litter were determined at 2, 7 and 14 weeks after placement (WAP). Results showed that inclusion of microarthropods significantly affect the nutrient concentration of different litters at different times after placement. Except for K, relative nutrient effect (RNE) of microarthropods decreased with increasing plant residue quality index (PRQI) and was significant for N (P<0.01), Ca (P<0.01) and Mg (P<0.05) indicating that residue quality plays important role in nutrient release and mineralization due to microarthropod activity. Results show that microarthropod activity increases N mineralization, and Ca and Mg release of fast decomposing residue.

Keywords: litter decomposition, nutrient release, mineralization, microarthropods, litter quality

Moor Journal of Agricultural Research Vol. 5(2) 2004: 95-101