Question

leguminous plants act as a natural fertilizers give reason

Answer 1

They act as a natural fertilizer as bacteria rizobium lives in the root nodules of leguminous plants and it converts the atmospheric nitrogen into water soluble form known as nitrates and it is a micronutrient needed by plants .
hope this will help you ......

Answer 2

no need for nitrogen compounds as rhizobium leguminoserum convert gaseous n2 into nitrus compounds