Abstract:
Objective The Yellow River Delta is a coastal saline wetland. The aim was to explore the characteristics and change mechanism of sodium adsorption in the soil around the key woody plant Tamarix in this area.
Method the spatial distribution and ion relationship of salt ions and sodium adsorption ratio (SAR) in the soil around Tamarix in the Yellow River Delta were analyzed by means of concentric circle sampling and correlation analysis.
Result The Cl− and Na+ were the main ions of soil salt composition around Tamarix. Na+, Cl− and Mg2+ were less in the topsoil close to Tamarix. The salt contents increased with the soil depth, showing a bottom aggregation. While, the soil far from Tamarix showed surface aggregation. The surface aggregation of Ca2+, SO42− and K+ was not affected by the distance from Tamarix. Correlation analysis showed that the soil SAR around Tamarix had a close relationship with Cl−, Na+, K+ and Mg2+ ions, and had the strongest correlation with Na+. In the 0 ~ 40 cm soil layer, the SAR value within 100 cm away from Tamarix was much lower than that outside 150 cm. The coefficient of variation of SAR decreased with the deepening of soil layer, and the correlation between SAR and salt ions in deep soil was not significant.
Conclusion The effect of Tamarix on SAR is more significant in 0 ~ 40 cm soil layer within 100 cm. The changes of soil salinity and SAR are affected by the crown range of Tamarix, plant root absorption, litter accumulation and precipitation leaching.
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