Soil Nutrient Characteristics and Fertility Evaluation of Wetland in the Lower Reaches of the Lhasa River

Abstract

[Objective] To explore the nutrient characteristics and fertility status of wetland soil in the lower reaches of Lhasa River. [Methods] A total of 69 soil samples were collected from the four representative regions of Ganqu Wetland, Baga Snow Wetland, Lalu Wetland and Chabalang wetland. The values of pH, total nitrogen, total phosphorus, total potassium, total salt, electrical conductivity, redox potential, cation exchange capacity and organic matter of the samples were determined. The improved Nemerow composite index method was used to evaluate the wetland soil fertility comprehensively. [Results] (1) The pH range of the soil in the study area was 5.77~7.78, with an average value of 6.62, which was neutral. The correlation between organic matter and total nitrogen was strong, and the distribution characteristics were similar. The contents of organic matter and total nitrogen were 61.82 and 3.13 g/kg, respectively, and both were very abundant, belonging to the first level. The contents of total phosphorus and total potassium were 0.75 g/kg and 18.05 g/kg, respectively, which were moderate and belonged to the tertiary level. The total salt content is 0.92 g/kg, and the electrical conductivity is 2.97 mS/m. On the whole, the soil in the study area had strong fertilizer retention ability. (2) The soil comprehensive fertility coefficient (P) of wetland was in the order of Chabalang Wetland (2.01) > Bagaoxue Wetland (1.95) > Lalu Wetland (1.93) > Ganqu Wetland (1.86), all belonging to the fertility level. The index affecting the soil comprehensive fertility of wetland was TP, because the formation conditions of natural wetlands were similar. There was no significant difference in soil comprehensive fertility coefficient. [Conclusion] The present situation of wetland soil nutrients in the lower Lhasa River was clarified, which provides scientific basis for realizing the sustainable utilization of wetland resources in the the study area.

Keywords

• lhasa river
• wetland
• nutrient characteristics
• fertility evaluation