The leaching characteristics of nitrogen and phosphorus fertilizers and their effects on ground water quality were investigated through soil columnnitrogen and phosphorus leaching experiments.
通过土柱模拟氮、磷素养分淋溶试验，研究了不同施肥处理下砖红壤氮、磷素淋溶损失特点。
2
Although there is 34,500 tons of gaseous nitrogen in the air column above each acre of the earth's surface, this cannot be used by plants until it has been fixed by nitrogen-fixing bacteria and algae.