# Effect of Planting _Portulaca oleraca_ L. on Improvement of Salt-Affected Soils
## 4 Discussion  
### Phytoremediation by P. olercea in Salt-Affected Soils  
In the phytoremediation of salt-affected soil, the efficiency of salt extraction highly depends on the characteristics of the selected halophyte species [23]. Ideal remediation plants should possess high biomass yield and strong salt absorption capacity. Therefore, when selecting remediation species, priority should be given to halophytes of the salt-accumulating type to fully utilize their efficient salt absorption and accumulation capabilities [24]. This study further revealed the unique ecological functions of _P. olercea_ in saline environments, particularly its ability to accumulate salt in its aboveground parts. It was found that the trend of ash salt content accumulated by _P. olercea_ in the different treatments was PS2 \(>\) PS3 \(>\) PS1. When harvested, the salt removal reached 1.29, 2.03, and 1.74 t/ha, respectively, in planting treatments under three salinity levels (Table 3). Notably, the ash salt accumulation (2.03 t/ha) in the PS2 treatment was particularly significant, equivalent to half of the ash salt accumulation of _Suada salsa_. Meanwhile, the ash salt accumulation in the PS3 treatment (1.74 t/ha) was comparable to that of _S. salsa_ at the seedling stage [18]. A similar study reported by [PERSON] et al. indicated that _P. olercea_ can effectively absorb salt in the soil, which can effectively remove 65 kg/ha of Na\({}^{+}\) and 210 kg/ha of Cl\({}^{-}\) in a growing season and accumulate these salts in aboveground parts, thereby reducing soil salt content [17]. These results indicate that _P. olercea_ exhibits similar salt-tolerance mechanisms to typical halophytes such as _Halogeton glomeratus_ and _Sueda glauc_[25]. Notably, _P. olercea_ not only adapts well to high-salinity environments but also effectively reduces soil salt content by accumulating salt in its aboveground biomass. This characteristic gives it significant application value in salt-affected soil remediation. Through regular cutting, _P. olercea_ can serve as an efficient phytoremediation tool, helping to reduce soil salinity levels while providing a sustainable solution for the ecological restoration of salt-affected soil. Additionally, the salt accumulation capacity of _P. olercea_ complements its salt tolerance mechanisms, further highlighting its adaptability and ecological value in adverse environments. Meanwhile, the salinity in the 0-10 and 10-20 cm soil layers decreased after harvest (Figure 1), demonstrating the strong desalination capacity of _P. olercea_. The possible mechanisms of desalination included the following: (1) the absorption and translocation of salt from the soil to the aboveground parts through transpiration, ultimately removing salt through harvesting; (2) the secretion of organic acids and other substances by _P. olercea_  
Figure 8: Effect of planting _P. olercea_ on alkaline phosphatase activity in salt-affected soils. Different lowercase letters above bars at the same soil depth indicate a significant difference at _p_\(<\) 0.05.  
roots, which promote the dissolution and leaching of salt ions in the soil; (3) the promotion of soil aggregate formation by root exudates, reducing surface salt accumulation.