Effect of lignin on N,P transformation in soil and corn yield

Effect of lignin isolated from black liquor of pulping process on N,P transformation in soil and corn yield has been determined. Results show that lignin can inhibit oxidization of NH₄⁺to NO₃^-,and the inhibiting effects increase with concentration.Both (NH₄)₂HPO₄ and (NH₄)₂SO₄ treatments are more effective for inhibiting nitrification than urea treatment when lignin is applied.Urea plus 2% and 5% lignin can reduce N₂O emissions by about 83% and 96%, respectively,while(NH₄)₂HPO₄ plus 2% and 5% lignin can respectively reduce N₂O emissions by 83% and 93%(30℃).Water-solubility P content in soil increases when lignin is applied.The results of potted test show that corn growth is better at lignin treatment than at non-lignin treatment.Lignin accelerates corn root and height growth.At concentrations of 50μg/g and 200μg/g,lignin increases corn yield 4.2% and 18.8%,respectively.