Relationships between Fine Roots Distribution and Soil Nitrogen Availability in Manchurian Ash and Korean Larch Plantation

Soil core method,in ash(Fraxinus mandshurica) and larch(Larix gmelinii) plantation(18 a) located in Maoershan Experimental Station,was used in study the relationships of root biomass,SRL(specific root length) and RLD(root length density) distribution and soil nitrogen availability within a growth season.Results showed that the distribution of fine roots and soil available Nitrogen(NO3——N and NH4+-N) were heterogeneous in two plantations.Average values of fine root parameters were higher in ash than larch,but CV of root parameters were consistent in two species.Fine root biomass and RLD distribution in natural soil environmental have positive relationships with soil N availability significantly(P0.5),but SRL has not this relationship.NH4+-N was highly relative to root distribution than NO3——N.These results showed that fine roots of two species have proliferation ability for foraging in nutrient rich patches.Ash fine root proliferation ability was higher than larch root.Fine root of larch maybe increased absorb rate and mycorrhiza quantity in rich patches to capture nutrients efficiently.