id	keyword
american_scientific_journal-7137	nutrient
american_scientific_journal-7137	nutrient solution
american_scientific_journal-7137	system
american_scientific_journal-7137	hydroponic
american_scientific_journal-7137	hydroponic system
american_scientific_journal-7137	level
american_scientific_journal-7137	plants
american_scientific_journal-7137	setup
american_scientific_journal-7137	lettuce
american_scientific_journal-7137	uptake