Biological, chemical and biochemical dynamics during litter decomposition at different depths in arable soil

G. Tripathi¹*, R. Deora¹ and J. Singh²

¹Department of Zoology, Jai Narayan Vyas University, Jodhpur- 342 001, India.

²Department of Entomology, Banaras Hindu University, Varanasi – 221 005, India

*Corresponding author. E-mail: drgst@rediffmail.com. Tel: 0291- 2722759.

Accepted 30 January, 2010

   Abstract

A field study was conducted to elucidate interactions among soil fauna, plant litter, soil nutrients and biochemical activities during litter decomposition in tropical desert land. Faunal association, nutrient dynamics, soil respiration and dehydrogenase activities were monitored in Hardwickia binata (T) tree based silvipasture system with Cenchurus cilliaris (CC) and Lesiurus sindicus (LS) grass. The faunal population varied significantly (P < 0.004) due to changes in litter quality. Faunal association was maximum in T + CC litter. The litter decomposition varied as a function of associated fauna in different litters. This proves that decomposition was influenced by litter quality and associated soil fauna. Faunal population and litter decomposition were maximum inside the canopy of tree at 5 cm depth indicating preferred niche for soil fauna. Soil organic carbon and soil nitrate nitrogen were significantly (P < 0.05) higher in the mixture of tree and grass litters than tree litter alone at different decomposition durations. The soil nutrients, soil respiration and dehydrogenase activity were significantly (P < 0.05) higher under the canopy zone. The nutrient enrichment and enhanced biochemical activities in the mixture of litters under the tree canopy at 5 cm depth may be due to the mixing and decomposition of a greater volume of litters by soil biota. However, soil organic carbon (SOC) was significantly (P < 0.05) higher at surface and minimum at 5 cm depth. It might be due to the loss of carbon as CO₂ by higher microbial population at 5 cm. A positive and significant correlation and interaction among litter associated soil fauna, litter decomposition, soil nutrients and biochemical properties during decomposition clearly demonstrated the positive impact of fauna on nutrient status, microbial and other biotic activities in silvipasture systems of arid region. The strategy may be adopted for enhancement of soil productivity through litter and fauna management in dry areas of the globe.       

Key words: Soil fauna, litter decomposition, nutrient dynamics, soil respiration, soil dehydrogenase activity.