Effects of Surface Soil Removal on Dynamics of Dissolved Inorganic Nitrogen in a Snow-Dominated Forest

Abstract

To clarify the effect of vegetation and surface soil removal on dissolved inorganic nitrogen (N) dynamics in a snow-dominated forest soil in northern Japan, the seasonal fluctuation of N concentrations in soil solution and the annual flux of N in soil were investigated at a treated site (in which surface soil, including understory vegetation and organic and A horizons, was removed) and control sites from July 1998 to June 2000. Nitrate (NO3) concentration in soil solution at the treated site was significantly higher than that of the control in the no-snow period, and it was decreased by dilution from melting snow. The annual net outputs of NO3 from soil at the treated site and control sites were 257 and –12 mmol m year, and about 57% of the net output at the treated site occurred during the snowmelt period. NO3 was transported from the upper level to the lower level of soil via water movement during late autumn and winter, and it was retained in soil and leached by melt water in early spring. Removing vegetation and surface soil resulted in an increase in NO3 concentration of soil solution, and snowmelt strongly affected the NO3 leaching from treated soil and the NO3 restoration process in a snow-dominated region.

Growth and substrate quality of fine root and soil nitrogen availability in a young Betula ermanii forest of northern Japan: Effects of the removal of understory dwarf bamboo (Sasa kurilensis)

“…Recently, it has been reported that the removal of S. kurilensis from a birch (Betula ermanii Cham) forest significantly increased the growth of the birch trees (Takahashi et al, 2003) due to greater availability of soil water. Ozawa et al (2001) have shown the effect of surface soil and vegetation removal on the dynamics of dissolved inorganic N in soil solution. Thus, an investigation on the growth and substrate quality of fine root in relation to altered soil N availability due to understory vegetation removal will be of great help in understanding the tree-undergrowth interaction for soil nutrients.…”

Ecological risks in anthropogenic disturbance of nitrogen cycles in natural terrestrial ecosystems

“…For example, nitrate leaching induced by forest management has been reported in a north Japanese forest with removal of surface soil and understory vegetation by scarification (Ozawa et al 2001;Shibata et al 2007), which is a treatment to promote regeneration of forests with avoidance of dominance of a single understory plant (Sasa senanensis). Nitrification and nitrate concentrations in soil water increased in the site with scarification, and were leached out in early spring by snow melt.…”

Changes in carbon stock following soil scarification of non-wooded stands in Hokkaido, northern Japan

“…Intensive soil disturbances such as soil scarification, as well as cultivation (Song et al 2005), can expose the ground to direct sunlight and increase soil temperature. The resultant high decomposition rate may limit the accumulation of organic matter during the age-sequences (Ozawa et al 2001). …”