Study the diagram given below and then answer the questions that follow:

(a) Briefly describe how nitrogen of the atmosphere is converted to nitrates by leguminous plants.

(b) Name the bacteria that converts (i) Ammonium compounds to nitrites (ii) Nitrites to nitrates

(c) State how the nitrates in the soil get converted to nitrogen of the atmosphere.

(d) Role of plants and animals in the formation of ammonium compounds.

(a) Soil bacteria such as Rhizobium are present in the root nodules of leguminous plants. These bacteria convert free nitrogen of the soil to soluble nitrates.

(b) The names of the bacteria are as follows:
    (i) Ammonium compounds to nitrites — Nitrosomonas
    (ii) Nitrites to nitrates — Nitrobacter

(c) Denitrifying bacteria in the soil break down nitrates present in the soil to release nitrogen gas which enters the atmosphere.

(d) Soil contains nitrifying bacteria that are crucial in converting nitrogenous wastes of dead and decaying matter of plants and animals to ammonia. This ammonia is then converted to ammonium compounds. This is how animals and plants assist in forming ammonium compounds.