Delineation of soil available DTPA-manganese status in Tirunelveli district of Tamil Nadu using GIS techniques

Abstract

A study was undertaken in Tirunelveli district of Tamil Nadu with a view to assess the micronutrient status of soils at block level. A sum of 1,798 geo-referenced surface soil samples from nineteen blocks of Tirunelveli district representing different soil units as per the soil map prepared on 1:50,000 scales were collected randomly at 0-15 cm depth using Global Positioning System. The soil samples were analysed for DTPA- Mn. The content of DTPA- Mn varied from 0.01 to 92.16 mg kg-1 soil. Analytical results and the GPS data were used for the preparation of thematic maps showing spatial distribution of micronutrients status block wise in the district. Locations of soil sampling sites of Tirunelveli district were marked on base map on 1: 50,000 scales prepared from State Revenue Maps and digitized using Arc-info GIS. The delineation study thus clearly indicates that, the deficiency status of DTPA –Mn was low to the tune of 15.4 per cents.