Assertion: clover's root | /r/CapableOf | help to keep nitrogen
Facets:
value: in the soil
type: LOCATION
Source sentences:
text: In the early 1900s, sweet clover was grown for forage and to build up the soil, since its roots help to keep nitrogen in the soil.
text: In the early 1900s, sweet clover was grown for forage and to build up the soil, since its roots help to keep nitrogen in the soil.