Micronutrient Status in a Dry Deciduous Tropical Forest of the Scrub Jungle of Mettupalayam, Coimbatore, India.
Subramanium Thiyageshwari, Duraisamy Selvi, and Sundarajan Amutha. Tamil Nadu Agricultural University, Lawley Road, Coimbatore District, Coimbatore, India
Plant nutrients are returned to the soil through litter fall from different forest covers and tree litter and prunings can substantially help to maintain soil organic matter and improve the physical properties of forest soils. As the information regarding micronutrients status under different tree ecosystems is not available, the present study was undertaken to assess the micronutrient status in soil as affected by different tree ecosystems of the eroded wastelands of dry deciduous forest of the scrub jungle of Forest College and Research Institute, Mettupalayam, Coimbatore, India. The soil is gravely with pH 7.2 and six block plantations of Bambusa bambus, Tectona grandis, Ailanthus excelsa, Azadirachta indica, Gmelina arborea) and Grevillea robusta aged from 5-11 years were selected for the study. Soil samples at two fixed depths of 0-30 and 30-60 cm, 1 m away from the base of the trees, were collected from each of the tree species and also from a nearby control, processed and analysed for pH and DTPA extractable Fe, Cu, Mn and Zn. The DTPA extractable micronutrients of the soil collected from tree stands indicated the increased availability of micronutrients compared to the control. In all the tree species, irrespective of the micronutrients, availability was higher in the soils at 0-30 cm than in the soils at 30-60 cm. Among the tree species, growth of silver oak (Grevillea robusta) raised soil pH above other trees species while at the same time had the lowest level of DTPA-extractable Fe. In general the pH of the soils were slightly acidic to alkaline and, unlike the micronutrient availability it increased with depth.