Your advice is sought to improve the nitrogen content of the soil to be used for cultivation of a non leguminous terrestrial crop
(a) Recommend two microbes that enrich the soil with nitrogen
(b) Why do leguminous crops not require such enrichment of the soil ?

Explanation

(a) Rhiobium Anabaena andazotobacter
(b) Because they can fix the atomospheric nitrogen Rhizobioum is a bacteria that lives in the roots of these plants .It converts the nitrogen in to the form that can be absorbed by the plant