Vol. 12, Issue 1 (2023)

Author(s):
S Suresh and J Sivakamipriya

Abstract:
Field experiments were conducted during kharif and rabi seasons of 2016-2017 and 2017-18 in clay soil of Agricultural Research Station, Thirupathisaram in high rain fall zone of Tamil Nadu to study the role of zinc solubilizing bacteria (ZSB), silicate solubilizing bacteria (SSB) and Potash solubilizing bacteria (PSB) for improvement in soil fertility and yield of paddy [var. ASD 16 (kharif) and TPS 5 (Rabi)] by taking the treatment combinations with ZnSO₄, rice husk ask (RHA) at fixed recommended fertilizer scheduled. The experimental soil had pH 7.40, EC 0.16 dS m^-1, organic carbon 0.44%, available silica 44 mg kg^-1, available N 205 kg ha^-1, available P 9.0 kg ha^-1 and available K 180 kg ha^-1. The result showed that the application of the recommended NPK + ZnSO₄ @ 25 kgha^-1 + RHA @ 2 tha^-1 recorded the highest number of productive tillers m^-2 with the mean value of 266 & 330 for the kharif and rabi seasons respectively. The above treatment also recorded the highest mean grain and straw yields during both the seasons (6.52 & 9.1 t/ha; 6.62 & 9.22 t/ha for the kharif & Rabi seasons respectively). The grain yield was 31.7 & 26.3% higher than application of Rec. NPK. The highest uptake of N, K, Zn, and silicon was observed in the above treatment. The application of microbial consortium II along with recommended N, P & K showed the highest soil available P than the other treatment combinations. The result showed that the application of RHA @ 2 tha^-1 along with recommended NPK proved to be superior for the clay soil of high rain fall zone for higher productivity in rice ecosystem. The B:C ratio was 2.28 & 2.40 during the kharif season and 2.12, 2.24 & 2.35 during the rabi season respectively during the different years studied. The residual soil showed marginal increase in the available silicon.