Continuous use of municipal sewage on soil physical and chemical properties

Abstract

An investigation was conducted on the physical and chemical properties of the sewage farm soil, Valiyathura in Trivandrum District. The sewage farm soil represents the loose sandy coastal alluvium. The area of the farm extends to 33 hectares under sewage water irrigation. From the farm area/6 blocks were selected representing 20 years and another 6 blocks representing 15 years of sewage irrigation.A comparative study was also made by choosing an adjacent block irrigated with well water. The whole area is cultivated with Napier and guinea grass Profile soil samples from different depths (0-15, 16-30, 31-45,. 46-i/70 cm) were collected for the determination of physical parameters such as bulk density, aggregate stability, stability index, hydraulic conductivity, water holding capacity and capillary and non capillary porosity. The soil chemical properties such as soil reaction electrical conductivity, organic matter content, total ammonical and nitrate nitrogen, total and available major nutrients, secondary nutrients micronutrients, cation exchange capacity and exchangeable cations were also determined from the soil samples collected at different depths. The plant nutrient content due to 15 year and 20 year sewage irrigation were also examined.