SOIL QUALITY ASSESSMENT BASED ON PHYSICO-CHEMICAL AND BIOLOGICAL PROPERTIES IN THE MANGROVE ECOSYSTEM OF ASRAMAM, KOLLAM, KERALA, SOUTH INDIA

A study was conducted to investigate the physical, chemical, and biological characteristics of soil in the Asramamwet lands of Kollam District, Kerala, South India, and to understand how these factors influence the distribution of mangrove vegetation in the region. Soil samples were collected randomly from rhizosphere and non rhizosphere areas of three representative locations within the wetland area. At each site, a soil pit of about 30 cm depth was prepared, and samples were collected from two distinct layers: 0-15 cm representing the top layer and 15–30 cm representing the bottom layer. The collected soil samples were transported to the laboratory for detailed analysis. Soilphysico-chemical properties, including soil pH, moisture content, electrical conductivity, soil organic carbon, and available nutrients such as phosphorus, potassium, calcium, sulphur, iron, zinc, manganese, copper, boron, and magnesium, were analyzed. In addition to these parameters, the biological aspect of the soil was assessed by estimating the percentage of root colonization by vesicular arbuscular mycorrhizal (VAM) fungi.The results revealed only minor variation in soil pH among the three study sites. Whereas electrical conductivity showed comparatively higher values in the topsoil. Organic carbon content was greater in the bottom layer than in the top soil. Among the nutrients analyzed, phosphorus, potassium, and calcium were more abundant in the topsoil, while sulphur, iron, and zinc were recorded in higher concentrations in the bottom layer.