Effects of Drying-rewetting Intensity and Frequency on the Inorganic Nitrogen and Net Nitrogen Mineralization of Hydrocotyle Vulgaris-soil System

Purpose Effects of altered precipitation patterns on natural ecosystems with climate change has already become a hot topic of ecological study. Our purpose was to reveal the effects of altered precipitation patterns on the inorganic nitrogen (N) and net N mineralization.

Method We conducted a greenhouse experiment with H. vulgaris across three drying-rewetting intensities and frequencies. We analyzed the content of nitrate and ammonium, net N mineralization and nitrification rate of the soils.

Result (1) Drying-rewetting intensity significantly affected soil inorganic N content of H. vulgaris. In the lowest drying-rewetting intensity, the ammonium content was the highest and nitrate content was the lowest than other two treatments. With drying-rewetting intensity increased, ammonium content decreased while nitrate content increased. (2) Drying-rewetting frequency significantly affected soil inorganic N content of H. vulgaris. With drying-rewetting frequency increased, ammonium content decreased while nitrate content increased. (3) There was a significant interactive effect between drying-rewetting intensity and frequency on soil inorganic N and net N mineralization.

Conclusion Our results suggested that altered drying-rewetting intensity and frequency can affect N availability and N cycle in plant-soil system, which indirectly affect the soil inorganic N, net N mineralization and nitrification rate of H. vulgaris.