Question

Green manure plants belong to.
A) Compositae
B) Solanaceae
C) Poaceae
D) Leguminosae

Answer 1

Hint:Green manure is defined as the plants which are grown and turned into soil to improve the soil quality. They are uprooted and sown into the soil or just kept there for an extended time period prior to tiling that land. they increase the fertility of the soil.

Complete answer:
Green manure provides and gives nutrition to the soil, decreases the soil porosity, makes it drought resistant and decreases the chances of soil erosion. It also lessens the alkalinity of alkali soil by generating humic and acetic acid. Some cover crops also rescue from insect pests and diseases due to these green manures. Green manures decrease the use of fertilizers and pesticides. If allowed to bloom, they function as food for pollinating insects.

Now let us find solution from given options:
A) Compositae : These are termed as a flowering family. The plants of this family are used as ornamental forms.
B) Solanaceae : Potato, brinjal and makka belong to this family. They are used as edible sources of food and they do not increase soil fertility thereby do not act as green manure.
C) Poaceae : This is the family of grasses. Wheat, maize, rice belongs to this family. These plants do not increase soil fertility.
D) Leguminosae : Generally, leguminous plants are used as green manure due to their symbiotic association with rhizobium species. Rhizobium can help to fix nitrogen from air to nitrate which is taken up by the leguminous plant. Thus, the concentration of nitrogen in leguminous plants is more in comparison to the non-leguminous.

Hence the correct answer is option ‘D’ i.e, Leguminosae

Note:leguminous plants are preferred and used as green manure. Non-leguminous plants are used to heighten the biomass which improves the water retention capacity, aeration etc. Crotalaria juncea and Alhagi camel belonging to families Fabaceae and Papilionaceae are used as green manures in crop fields and in sandy soils. These plants are fast growing, and they possess high nutrient accumulation capability. They protect from floods, and make them drought resistant.