Canopy and understory nitrogen addition have different effects on fine root dynamics in a temperate forest: implications for soil carbon storage

Here,
we conducted a field experiment comparing the effects of canopy addition of N
(CAN) with understory addition of N (UAN) at three N-addition rates (0, 25, and
50 kg N ha^–¹ yr^–¹)
on fine root dynamics in a temperate deciduous forest.

Fine root production and biomass were significantly higher with CAN
than with UAN. At
the same N-addition rate, increases in fine root production with CAN were at
least 2-times greater than with UAN. At the high N-addition rate and
relative to the Control, fine root biomass was significantly increased by 23.5%
by CAN but was significantly decreased by 12.2% by UAN.