Assertion: sitka alder | /r/CapableOf | add nitrogen
Facets:
value: to the soil
type: TRANSITIVE-OBJECT
Source sentences:
text: Studies show that Sitka alder, a more shrubby variety of alder, adds nitrogen to the soil at an average of 55 pounds per acre (60 kg per ha) per year, helping convert the sterile glacial terrain to soil capable of supporting a conifer forest.