Agroecosystem-chemical interactions and trends.
D000383:Agriculture; D002244:Carbon; D002622:Chemistry, Agricultural; D004463:Ecology; D009584:Nitrogen; D011868:Radioisotopes; D012987:Soil / Q000032:analysis
D011868:Radioisotopes; D012987:Soil; D002244:Carbon; D009584:Nitrogen