Spatial And Temporal Patterns Of Fine Root Biomass And Nutrient Distribution In Four Forest Types In The Xiaoxing’an Mountains

To compare the differences of the Spatial and Temporal Patterns between typical primary, secondary forests and plantations ecosystem on fine roots and the Soil physical and chemical properties, grasped the effect factors of dynamics of fine root biomass and Soil physical and chemical properties in different models of plantation, comprehended the interactions between fine roots and edaphic environment, clarified the carbon(C) and nutrient cycling in forest ecosystem and to provide theoretical evidence for forest recovery and management in this region.A field experiment was carried out to investigate the vertical distributions, seasonal dynamics, Soil physical and chemical properties on fine root biomass in the Mixed broadleaved-Korean pine (Pinus koraiensis) forest, Secondary birch (Betula platyphylla) forest (natural regeneration after clear cutting), Korean pine plantation (artificial planting after clear cutting) and Dahurian larch (Larix gmelinii) plantation (artificial planting after clear cutting) from May to September of 2013. Fine roots (≤2 mm in diameter) were sampled using sequential root coring method. The results showed that,(1) Fine root biomass in the mixed broadleaved-Korean pine forest (3.55 t·hm-2) and Korean pine plantation (3.37t·hm-2) were significantly higher than those in Secondary birch forest (2.63 t·hm-2) and Dahurian larch plantation (2.30 t·hm-2) (P<0.05). There were significant differences in the vertical distribution on fine root biomass of 4 forest types (P<0.05). Fine root biomass mainly concentrated in the 0-20 cm soil depth, and those in 0～20 cm depth had the highest percentage in the Secondary birch forest (75.81%) and the lowest in the Mixed broadleaved-Korean pine forest (62.73%). Fine root biomass showed significant seasonal dynamics (P<0.05). In each forest type, fine root biomass and necromass showed two peaks respectively during the experiment and the peaks appeared in different months.(2) There was no significant correlation between soil temperature and fine root biomass in all 4 forest types, but there were highly significant positive correlation between soil moisture content and fine root biomass in 3 forest types (except the mixed broadleaved-Korean pine forest) (P<0.01). The content of Hydrolysis nitrogen had highly significant positive correlation with fine root biomass in all 4 forest types (P<0.01) while the Available phosphate was significant negative correlated with fine root biomass in the Secondary birch forest.(3) The content of fine root total nitrogen had significant differences in all 4 forest types. The content of live fine root total nitrogen in Secondary birch forest were significantly higher than those in the mixed broadleaved-Korean pine forest and Korean pine plantation (P<0.05), but no significant differences between Dahurian larch plantation and other 3 forest types. The content of dead fine root total nitrogen in Secondary birch forest were significantly higher than other 3 forest types (P<0.05). The content of live fine root total phosphorus in Korean pine plantation and Dahurian larch plantation were significantly higher than those in the mixed broadleaved-Korean pine forest and Secondary birch forest (P<0.05), but there was no significant differences of the content of dead fine root total phosphorus in 4 forest types. There were significant differences in the vertical distribution and seasonal dynamics on fine root total nitrogen and phosphorus content in 4 forest types (P<0.05).