An field experiment was conducted in zinc deficient soil belonging to Padugai series (Typic Ustifluevents) at the farmer’s holding during the Navarai season of year 2017.The treatments consists of viz., T1 - Absolute control , T2 - NPK (RDF), T3 - RDF + ZnSO4 @ 25 kg ha-1 , T4 - RDF + Nano zinc (Granules @ 10 kg ha-1 ),T5 - RDF + Nano zinc (Granules @ 15 kg ha-1 ),T6 - RDF + Bio zinc (Granules @ 10 kg ha-1 ),T7 - RDF + Bio zinc (Granules @ 15 kg ha-1 ),T8 - RDF + Foliar spray of 0.5 % as ZnSO4 at T.S and P.I.,T9-RDF + Foliar spray of 1 ml L-1 as nano zinc at T.S and P.I. and T10- RDF + Foliar spray of 1.5 ml L-1 as bio zinc at T.S and P.I.. The test crop was rice var.CO 51. The results revealed that enzymes activity was significantly enhanced on addition of different sources of zinc over control. The enzymatic activity increased with the age of the crop and the highest activity was seen at panicle emergence stage and decreased at harvest. Among all the treatments RDF + soil application of bio zinc @ 30kg ha-1 and RDF + soil application of Zn SO4 @ 25 kg ha-1 recorded the highest urease activity and was on par with each other at all stages. Similarly dehydrogenase, acid and alkaline phosphatise activity highest was observed in the treatment receiving and RDF + Soil application of Bio zinc @ 30kg ha-1 .
