Subjects: Geosciences >> Geography submitted time 2024-06-12 Cooperative journals: 《干旱区研究》
Abstract： Seed germination and the seedling growth of sand-fixing plants are decisive aspects of land desertifica- tion management, and soil moisture is the main limiting factor affecting these aspects. In this study, we compared and analyzed the seed germination of three sand-fixing plants under different moisture gradients (4%, 6%, 8%, 10%, 15%, 20%, and 25%) in an indoor potting experiment using Hedysarum scoparium, Caragana korshinskii, and Artemisia desertorum to investigate the response of seed germination and seedling growth of sand- fixing plants to changes soil in moisture. The results showed that: (1) significant differences (P<0.05) were observed in the seed germination characteristics of the three sand-fixing plants as the soil moisture increased. The germina- tion rates tended to increase and then decrease as the soil moisture increased. C. scoparium had the highest germi- nation rate at 15% and 20% soil moisture (83.00% in both); C. korshinskii had the highest germination rate at 10% soil moisture (73.00% ); and the seed germination rate of A. desertorum reached the maximum value of 77.50% at 15% soil moisture, and then slowly decreased, although the change was not significant. (2) The leaf ar- ea and root length of the three plants showed tended to first increase and then decrease as the soil moisture in- creased, and the specific leaf area and root:crown ratio tended to decrease and then increase. (3) The highest bio- mass of C. scoparium, C. korshinski, and A. desertorum seedlings was 0.0733 g, 0.1142 g, and 0.0363 g at 10%, 8%, and 20% soil moisture, respectively, and the aboveground biomass was significantly higher than the below- ground biomass (P<0.05), although the allocation of belowground biomass by C. korshinski seedlings was higher than that of C. scoparium and A. desertorum. (4) The SOD activity, POD activity, CAT activity, Pro content, SS content, and Chl content of the three sand-fixing plants tended to increase and then decrease as the soil moisture increased, whereas the MDA content, membrane permeability, and relative water content tended to decrease and then increase. Based on the above results, it was concluded that the three sand-fixing plants of C. scoparium, C. korshinski, and A. desertorum had the best seedling growth at 15% , 8% and 8% soil moisture, respectively, through the analysis of the affiliation function method. Therefore, when these three sand-fixing plants are used for vegetation restoration, the changes in soil moisture caused by rainfall conditions should be fully considered in addition to the seeds’own traits to improve the seedling emergence rate and the success of seedling growth.
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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