Study of the Soil Properties and the Bentonite Clay to Reduce Water Loss from the Fish Ponds

Abstract

Water loss from the fish pond due to seepage and percolation has been the major problem of farm managers in the semi-arid and arid regions. The soils of such regions have been characterized for low clay content, deep water table, high CaCO3 and high potential evaporation. This leads to very high water loss rates from the fish ponds. In an effort to overcome the problem of water loss, an experiment was conducted at the farm site of National Bureau of Fish Genetic resources, Lucknow. The experiment was conducted in eight pits (total surface area 57.44 m2 and volume 30.34 m2), which were divided into two groups, each consisting of four pits. The first group was having high CaCO3 and other was having low CaCO3. Composite sample were taken from these pits and were analyzed for texture, bulk density, true density, pH, CaCO3 and organic carbon. The readings on daily water loss and on pan evaporation rate were recorded in relation to clay, silt, sand and CaCO3 and also after application of bentonite treatment. The results showed marked reduction in . water loss after application of a coating of 5% bentonite and 95% local soil mixture. The seepage rate was much higher in the pits having higher CaCO3 content. It was concluded from this study that presence of CaCO3 content of the soil increase the water loss which requires treatment to reduce the water percolation to a manageable level in a fish farm.