Abstract

A study was carried out for determining the effect of various carriers and storage temperatures on survival of Azotobacter vinelandii NDD-CK-1. The experiment was laid out using a 4 x 5 factorial treatment arrangement in a Completely Randomized Design with three replications. The first factor is carrier with four kinds, viz. peat (Pt), peat mixed with corn stubble compost (PtCC), peat mixed with golden flamboyant leaf compost (PtLC), and Pt mixed with mushroom waste compost (PtMC). The second factor is storage temperature with five levels, viz. -16 ^oC, 5 ^oC, 25 ± 2 ^oC, 30 ± 2 ^oC and 37.5 ± 2.5 ^oC. Inoculum of Azotobacter vinelandii NDD-CK-1 was produced by a standard method using various carriers. The results revealed that types of carrier, storage temperatures and interaction between them showed significant effect on survival of azotobacter during 7 to 90 days. The survival rate was the highest in PtLC, followed by PtCC, PtMC, and Pt which gave the log number of bacterial viable cell of 6.41, 6.02, 5.67 and 5.50, respectively. The proliferation of azotobacter decreased with time and increasing temperature. The appropriate storage temperature at 7 to 15 days was -16 ^oC, while the most suitable temperatures for longer term (30 to 90 days) was 5 ^oC; followed by -16 ^oC, 25 ± 2 ^oC, 30 ± 2 ^oC and 37.5 ± 2.5 ^oC. The highest survival of azotobacter was found in PtCC at -16 ^oC (9.98 log cfu/g), similar to PtCC at 5 ^oC, PtLC at -16 ^oC, and PtLC at 5 ^oC (9.92, 9.85 and 9.77 log cfu/g, respectively).

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