S. Raghavendra, J. Vishwanath, M.A. Bellakki, M.V. Ravi, K. Narayan Rao and K.M. Prashanth
Abstract
A laboratory incubation experiment over a period of 12 weeks was conducted during 2012-13 at Agricultural Research Station, Gangavati to study the effect of different organic amendments with or without gypsum on soil ESP and the availability of micronutrients (Zn, Fe, Mn and Cu) in a sodic soil having ESP 24.6. Two-hundred fifty gram of processed 2 mm sieved soil was filled in a plastic container (350 g capacity) having holes on the corner of the bottom of the container. A total of 60 plastic containers representing six treatments of three replications each were incubated under laboratory conditions maintaining moisture at field capacity. Except the control (T1), ESP decreased from the third day/ first week to the 12th week of incubation in other five treatments. The extent of reduction in ESP over the incubation period was 51.6, 49.6, 47.2, 44.7 and 31 per cent in T4 (50 % GR + FYM), T2 (100 % GR), T6 (50 % GR + Green manure), T5 (50 % GR + Paddy straw) and T3 (50 % GR) respectively over the control. The maximum increase in DTPA-Zn over the incubation period was observed in T6 (50% GR + Green manure). Overall, an increase of 165, 156, 147, 128 and 97 per cent over initial Zn level was observed in T6, T4, T2, T5 and T3 respectively. The maximum increase in DTPA-Fe was observed T6. Overall, an increase of 129, 126, 122, 104 and 95 per cent over initial Fe level was observed in T6, T4, T2, T3 and T5 respectively. An increase of 94, 93, 85, 83 and 81 per cent of DTPA-Mn over initial was observed in T5, T6, T3, T4 and T2 respectively. About 10 to 16% increase in the DTPA-Cu content was observed over the incubation with the maximum of 16% in T6.