土壤有机碳 - 有机氮比值 organic carbo-nitrogen ratio in soil
生物固氮作用(Biological nitrogen fixation)
联合固氮作用 associative nitrogen fixation
氮循环 nitrogen cycle
氮转化 nitrogen transformation
铵态氮肥 ammonium nitrogen fertilizer
氮平衡 nitrogen balance
氮代谢 nitrogen metabolism
固氮基因 nitrogen fixation genes