Abstract: In order to study the effects of chicken manure and lignin treatment on nitrate metabolism in soil of the root zone of Malus hupehensis Rehd., the changes of nitrate metabolism in soil were analyzed by using pot experiments, with the treatment of adding mass fraction 12.5% chicken manure, 12.5% chicken manure + 1.5 g/kg lignin and 12.5% chicken manure + 2.5 g/kg lignin, sampling in the spring, summer, and autumn. Results showed that the application of chicken manure and lignin inhibited the transformation rate of ammonium nitrogen to nitrate nitrogen in soil compared with single application of chicken manure, reduced the nitrification intensity of soil. The more lignin was applied, the more obvious the inhibitory effect was. And the effect on the denitrification intensity of soil was different in each season. Lignin increased the activity of nitrate reductase and nitrite reductase in soil, as well as increased the content of ammonium nitrogen in soil, and reduced the content of nitrate-nitrogen in soil. The application of lignin could significantly inhibit the loss of nitrogen in soil, which provided a theoretical basis for the rational application of lignin.

Key words: chicken manure, lignin, Malus hupenensis Rehd., nitrate metabolism, soil nutrient