Stoichiometry characteristics of carbon, nitrogen, and phosphorus in leaf-litter-soil interactions of Haloxylon ammodendron plantations with different stand ages

To reveal the changes in stoichiometry characteristics of leaf-litter-soil interactions of Haloxylon ammodendron plantations and their influencing mechanisms.

Using Haloxylon ammodendron plantations with different stand ages (3, 6, 11, 16 and 35 years old) in the Jilantai desert area of Inner Mongolia as the study objects, the changes in carbon (C), nitrogen (N), phosphorus (P) stoichiometry in Haloxylon ammodendron leaves, litter, and soil and their interrelationships were analyzed.

The results showed that: 1) Stand age had a significant effect on leaf, litter and soil C, N and P contents and stoichiometric ratios (P<0.05). The average carbon, nitrogen, and phosphorus contents of Haloxylon ammodendron leaves, litter, and soil were in the order of leaves > litter > soil. The C∶N, C∶P and N∶P were in the order of litter > leaves > soil; 2) At the depth of 0-20 cm, soil C∶N was significantly negatively correlated with leaf C∶N and C∶P, and extremely significantly negatively correlated with litter C∶P and N∶P; soil C∶P was significantly negatively correlated with leaf C∶N, C∶P, litter C∶P and N∶P; and soil N∶P was significantly negatively correlated with litter C∶P. Soil C∶N, C∶P, and N∶P were not significantly correlated with leaf/litter C∶N, C∶P, and N∶P at 20-60 cm soil depth; 3) Limiting factors for litter and leaves were inconsistent between shallow and deep soils. At the depth of 0-20 cm, soil C∶P and pH were important factors affecting nutrient content and stoichiometry of Haloxylon ammodendron leaves; soil C∶N and soil bulk density (BD) were important factors affecting nutrient content and stoichiometry of Haloxylon ammodendron litter. At the depth of 20-60 cm, soil total nitrogen (STN) and pH were important factors affecting nutrient content and stoichiometry of Haloxylon ammodendron leaves and litter, respectively.

The research results are beneficial for further clarifying the interaction patterns and mechanisms of carbon, nitrogen, and phosphorus in the leaf-litter-soil interactions of Haloxylon ammodendron plantations in desert areas.