The changes of nutrient limitation status for tree growth across a plantation chronosequence have great implications for plantation management. The underlying mechanisms for such a shift, however, have seldom been addressed. While plant nutrient use strategies would change in response to soil nutrient alteration, they may also create feedback on soil nutrient dynamics and thus plant nutrient limitation status.
We examined soil and foliar nutrients of larch (Larix kaempferi), the dominant timber species in Northeast China, across a plantation chronosequence.
Total soil N increased but total soil P decreased across the chronosequence. Similarly, N concentrations in the green leaves were positively correlated, and P concentrations were negatively correlated with stand age. Foliar N:P ratios, N and P resorption efficiencies and PRE:NRE were positively correlated with stand age, indicating the shift from N-limitation to P-limitation across the chronosequence. P concentration in senesced leaves decreased and N:P ratios increased across the chronosequence, which has implications for decomposition and nutrient release.
Nutrient resorption, soil pH, biomass P sequestration and imbalanced inputs of N and P would contribute to the occurrence of P-limitation with increased stand age. Furthermore, adaptive fertilization management strategies should consider the shift of nutrient limitation patterns across the chronosequence. |
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