id	keyword
american_scientific_journal-7018	soil
american_scientific_journal-7018	compaction
american_scientific_journal-7018	probe
american_scientific_journal-7018	improvement
american_scientific_journal-7018	terra
american_scientific_journal-7018	material
american_scientific_journal-7018	columns
american_scientific_journal-7018	introduction
american_scientific_journal-7018	technique