The soil C:N:P stoichiometry is more sensitive than the leaf C:N:P stoichiometry to nitrogen addition: a four-year nitrogen addition experiment in a Pinus koraiensis plantation

Aims The atmospheric deposition of N has rapidly increased in recent years, but whether the C:N:P stoichiometry of older leaves, litter and the mineral layer of soil is more sensitive to N deposition than the C:N:P stoichiometry of new leaves remains unclear. Methods An experiment simulating N deposition (0, 20, 40, and 80 kg center dot N center dot ha(-1)center dot year(-1)) was established in a Pinus koraiensis plantation in Northeast China in May 2014. In September 2017, the nutrient concentrations in new and older leaves, litter, and the 0-10 cm and 10-20 cm soil mineral layers were determined. Results The treatments and leaf stages had no significant interaction effect on the leaf C:N:P stoichiometry. The coefficient of variation among the treatments found for new leaves was significantly lower than that found for the 10-20 cm soil layer, and no significant difference was found among the three leaf stages or among the two soil layers. Conclusions The C:N:P stoichiometry of older leaves and litter is not more sensitive to N addition than that of new leaves, and the soil C:N:P stoichiometry responds earlier to N addition than the leaf C:N:P stoichiometry. For the forest ecosystem factors associated with stoichiometric traits, the soil C:N:P stoichiometry might be a better indicator of variations under the increased N:P deposition ratio obtained with N deposition.