Effect of arbuscular mycorrhizal (AM) fungi inoculation on enzymatic activity and zinc uptake under direct seeded rice system

The application of treatment T3 (Glomus mosseae + 100 % RDF NK) produced significantly more root volume by 72.60 %, 17.80 %, 12.25 %, 14.13 % over the application of treatment T1 (Control), treatment T5 (Glomus coronatum+ 100 % RDF NK), T6 (Gigasporadecipein + 100 % RDF NK) and T7 (BAU AM-1(Glomus sp + 100 % RDF NK), respectively. Similar trend shows at harvesting stage, here the maximum root volume (23c.c) was recorded by the application of T3 (Glomus mosseae + 100 % RDF NK). Maximum AM colonization and spore count was observed at panicle initiation stage with the application of treatment T3 (Glomus mosseae + 100 % RDF NK). This treatment also gave maximum dehydrogenase activity (55.86 µg TPF g-1 24 hr-1), acid phosphatase activity (0.299 mg PNP g-1 hr-1) and alkaline phosphatase activity (0.54 mg PNP g-1 hr-1) at panicle initiation stage. Application of treatment T3 (Glomus mosseae + 100 % RDF NK) significantly increased DTPA extractable Zn in soil and Zn content in plant when compared with all the treatments except treatment T6 (Gigasporadecipien+ 100 % RDF NK). The maximum zinc uptake (0.056 mg pot-1) by grain was recorded under treatment T3 (Glomus mosseae + 100 % RDF NK) followed by application of treatment T6 (Gigasporadecipien + 100 % N and K). Highest grain yield (14.08 g pot-1) was found with the treatment T3 (Glomus mosseae + 100 % RDF NK). As evident from the results, the AM fungal inoculation can effectively modify the soil microbe population and community structure by increasing the soil enzymatic activities and significantly increased the zinc uptake by grain in direct seeded rice (DSR)