| Premature aging has been observed to varying degrees in the growth and development of Pinus sylvestris plantations in arid regions. This study investigated the soil physicochemical properties, including organic matter, available phosphorus (P), available potassium (K), nitrate nitrogen (NO-3-N), and ammonium nitrogen (NH+4-N), in 8-year-old pure plantations of Pinus sylvestris and mixed plantations of Pinus sylvestris × Viola philippica. A typical sampling method was used to assess soil samples across three depths (0~5 cm, 5~15 cm, and 15~25 cm). The results showed that:Except for ammonium nitrogen, the soil nutrient content of pure forests decreased with increasing soil depth. In the 0~5 cm soil layer, the organic matter and ammonium nitrogen contents in mixed forests were higher than in pure forests, with ammonium nitrogen being statistically significant. In the 5~15 cm and 15~25 cm soil layers, the organic matter and nitrate nitrogen contents in pure forests were significantly higher than in mixed forests.The available potassium and phosphorus contents in mixed forests decreased initially and then increased as soil depth increased. In the 15~25 cm soil layer, the available phosphorus content in mixed forests was significantly higher than in pure forests.The soil water content in all layers of mixed forests was higher than in pure forests, with a statistically significant difference observed at the 15~25 cm soil layer. |
