Effects of Litter Decomposition on Soil N in Picea mongolica Forest at Different Forest Ages

In order to study the effects of litter decomposition on soil nitrogen Piceamongolica in different forest ages, young (0–5a), middle-aged (5–30a), and near-mature (30–40a) stands were selected Baiyinaobao National Nature Reserve. Litter was assessed using bag method. The seasonal vertical spatial variation characteristics total N, NH4+—N, NO3−—N caused by P. mongolica studied for stand ages. Results showed that: (1) There a positive correlation between N content organic matter, content, across ages (p < 0.05). negative NH4+—N contents. A C contents also observed. (2) this study, increased with increase during decomposition.NH4+—N positively correlated sample date, NO3−—N, age 0.05), negatively depth 0.01). date significantly (3) is greater than that each layer three analysis indicated which factors influenced soil. decreased February November May August. (4) soils (0–50 cm) an overall downward trend. from (0–10 cm, 10–20 cm 20–30 30–40 40–50 differed as did results while depth. no significant difference content. (5) trend mature > forest. This consistent Picea