Role of epigeic earthworms on trophic group of nematodes during organic matter decomposition in litter bags under tomato cropping on ultisol

Abstract

Epigeic earthworms are often used to restore of soil quality. Trophic group of nematodes plays an important role in driving of decomposition rate of organic matter. Ultisols is characterized with the soil biological quality that is not suitable for the development of vegetable crops. The objective of this study was to analyze the effect of epigeic earthworms on the abundance of nematode trophic groups during the decomposition of organic material in litter bags under cropping of tomato (L. esculentum Mill.) on Ultisols. Epigeic species of earthworms (Lumbricus sp.) were used to modify the soil environment. The experiment treatment consisted of nine combinations of three types of organic matter and three individual levels of earthworms. The organic material consisted of litters of C. odorata, I. cylindrica and Colopogonium sp. The number of earthworms consisted of 0, 20 and 40 individuals plot−1. Each combination of each litter type and number of earthworms was repeated three times in an experimental randomized block design. Research found three trophic groups of nematodes, namely root-herbivorous, bacterivorous and predaceous in the litter bags. Abundance of root-herbivorous between combinations was significantly different at 30 days after exposure. Abundance of bacterivorous nematodes among treatments was significant at 60 days after exposure, which at the 30 and 90 days were not significant. Abundance of predaceous was differed significantly at the 60 and 90 days, and at the 30 days was not significantly different. Constant of decomposition rate of each organic matter under different number of earthworms was similar. Coefficient correlation showed that relation between the constant of decomposition rate with abundance of root-herbivorous was positive at 30 days and negative with bacterivorous at the 90 days. Research concluded that the introduction of epigeic earthworms influenced trophic group dynamics of nematodes during the decomposition of organic material under tomato cropping on Ultisols.