Question

Question #1d904

Answer 1

Soil

Explanation:

The major reservoir of diatomic nitrogen `(N_2)` is atmosphere. But neither plants nor animals can obtain directly from atmosphere.
Thus from here, the work of nitrogen fixing bacteria starts.

These bacteria are present in the root nodules of leguminous plants. These bacteria convert the nitrogen present in soil into amino acids which can be taken by plants.

Further these amino acids are converted into ammonia `(NH_3)` by certain soil dwelling organisms in process called ammonification.

That's the reason that Soil is major reservoir of ammonia and also of other nitrogen containing compounds.