Abstract

                                To assess the nutrient release pattern of tank silt, an incubation experiment was conducted at Pandit Jawaharlal Nehru College of Agriculture and Research Institute, Karaikal with thirteen treatments, in which the soil was incubated with tank silt (TS) and organic manures viz., press mud (PM), sewage sludge (SS), water hyacinth compost (WHC), FYM and spent wash (SW) and tank silt blended with organic manures. The incubation was carried out for 120 days and soil samples were drawn at 0, 30, 60, 90 and 120 days of incubation. With the advancement of incubation period the pH and organic carbon declined sharply, whereas, the EC and soil available nutrients increased with duration of incubation. The simple linear regression had shown that the pH decreased at a rate ranging from 0.0047 units day-1 (soil alone) to 0.0079 units day-1 (soil+TS+FYM). The decrease in organic carbon content ranged from 8.0 g kg-1 day-1 in soil amended with tank silt to 19.6 g kg-1 day-1 in soil+TS+SW. The rate of release of KMnO4-N, Olsen-P, NH4 OAc-K, NH4 OAc-Ca, NH4 OAc-Mg and CaCl2 -S ranged from 0.014 to 0.651, 0.028 to 0.102, 0.214 to 2.033, 0.195 to 0.803, 0.106 to 0.459 and 0.060 to 0.621 respectively. It was observed that the suitable blending of tank silt with organic manures could result in a complete organo mineral product which through increasing mineralization potential will definitely result in better release of nutrients.

Key words : Tank silt, Organic manures, Nutrient release pattern, Available nutrients