Growth performance and nitrogen use efficiency of two Populus hybrid clones (P. nigra × P. maximowiczii and P. trichocarpa × P. maximowiczii) in relation to soil depth in a young plantation

摘要

It is a challenge to produce woody crops on marginal land. The goal of this study was to examine growth responses and nitrogen use efficiency of different poplar species on shallow soil. Typical biomass poplar clones of Max1 (P. nigra × P. maximowiczii) and H275 (P. trichocarpa × P. maximowiczii) were planted on a marginal site where a gradient in soil depth was present. The growth, biomass production, and nitrogen uptake rate as well as nitrogen use efficiency of Max1 and H275 were determined for three consecutive years. Both poplar clones showed decreased growth and biomass production in the shallow soil. Max1 showed better adaptation to shallow soil with higher survival rate and more biomass production than H275. Max1 had lower nitrogen use efficiency on shallow soil than H275. The results suggest that higher nitrogen uptake of poplar species might be an important adaptation to maintain productivity under unfavorable soil conditions.