Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： Due to the interference from human activities and natural factors, the primary sierozem area in theNingxia desert steppe has gradually shrunk due to long-term desertification and formed island patches within thesurrounding aeolian soil. To reveal the spatiotemporal characteristics of soil moisture after sierozemdesertification, a comparative study was carried out between the large (200-300 m2), medium (approximately 100m2), and small (approximately 50 m2) sierozem patches and the surrounding aeolian soil in Wanjigou Village,Yanchi County, Ningxia, during the growing season (May to October from 2017 to 2019). The uniform rainfallpattern in 2017 led to the highest annual average soil moisture content. While the annual rainfall in 2018 wasslightly higher than that in 2017, it was concentrated in the spring, and there were almost no rainfall events in thesummer and autumn, resulting in a low soil moisture content throughout the year. The summer rainfall pattern in2019 resulted in the highest average soil moisture content during the summer period. The soil moisture content ofsierozem in the 0-100 cm soil layer first showed an increase and then a decrease with increases in soil depth andwas greatest in the 10-40 cm soil layer. The soil moisture content of the aeolian soil increased with soil depth,and the soil moisture content of the 0-20 cm soil layer was much lower than that of the 20-100 cm layer. Themoisture content of sierozem in the 0-20 cm soil layer was greater than that of the aeolian soil, while themoisture content of the sierozem in the 20-100 cm soil layer was significantly lower than that of the aeolian soil(except for small and medium-sized patches in 2018). There was no significant difference (P > 0.05) in the soilmoisture content of the sierozem between the different patch sizes, except that the soil moisture content of theaeolian soil surrounding the large-sized patches was significantly greater than that of the small and medium-sizedpatches (P < 0.05). The water storage of sierozem in the 0-100 cm soil layer was generally lower than that of theaeolian soil, and the variation range was smaller than that of the aeolian soil during the same period. When therainfall was <16 mm, the water in both soil types was in a consumption state. When the rainfall ranged from 16 to25 mm, the water storage capacity of the sierozem was greater than that of the aeolian soil, but when the rainfallwas >25 mm, the water storage capacity of the aeolian soil was greater than that of the sierozem. The soilmoisture content in the desert steppe was dominated by the rainfall, its distribution pattern, and soil type. Themoisture contents of the sierozem and aeolian soils differ in their profiles, as well as in response to rainfall.
Subjects: Geosciences >> Geography submitted time 2023-12-16 Cooperative journals: 《干旱区研究》
Abstract： To explore the main factors influencing soil salinization in irrigation region of Yellow River of Hongsipu, correlation analysis and principal component analysis were used to study the salinization characteristics of the 0-100 cm soil profile. The results showed the following: (1) The overall soil in the study area is strongly alkaline, with the pH of the lower layer of 20-100 cm soil being significantly higher than that of the upper layer of 0-20 cm (P<0.05), which increases with increasing soil depth. The total salt content of soil also increases with increasing soil depth, showing a bottom aggregation-type profile feature of high at the bottom and low at the surface. The difference in total salt content of each layer of soil was not significant (P<0.05), which the pH of each layer of soil exhibited weak variability, with a relatively uniform spatial distribution. The total salt content of soil in the upper layer showed moderate variability at depths of 0-20 cm, while in the lower layer of depths of 20-100 cm it showed strong variabilily, with differences in spatial distribution appearing with changes in depth. (2) The main cation in the study area is Na++K+, with significant differences in the content of each cation (P<0.05). The main anion is SO2- 4 , which significant difference compared with other anions (P<0.05). The contents of the ions are in following order: SO2- 4 > Na+ +K+ > Ca2 + > Mg2 + > HCO-3 > Cl− > CO2- 3 , and the concentration of each ion also increases with increasing of soil depth, consistent with the changes in total salt and pH. (3) Through correlation analysis and principal component analysis, it was found that the main factors affecting total salt in the irrigation area are SO2- 4 , Cl−, Na++K+, and Mg2+, while the main factors affecting pH are CO2- 3 and HCO-3 . The main salts are sulfate and chloride, but there are significant differences in salt types at different depth profiles. The upper layer of salt is mainly chloride, while the lower layer is a composite of sulfate and chloride. The results of this study prove the main factors affecting the soil salinity characteristics of irrigation region of Yellow River of Hongsipu, and provide a theoretical basis for the treatment of alkali soil in the study area.
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