Phosphorus Speciation Characteristics of Typical Artificial Vegetation Rhizosphere Soil in Mu Us Sandy Land

Artificial vegetation plays an important role in the restoration of the ecosystem in Mu Us Sandy Land. Understanding the phosphorus (P) forms in the rhizosphere and bulk soils of typical artificial vegetation can provide a basis for scientific vegetation construction in the area. The rhizosphere soil and bulk soil of seven typical artificial vegetations (Pinus sylvestris, Populus simonii, Amygdalus pedunculata, Amorpha fruticosa, Salix psammophila, Sabina vulgaris, and Artemisia ordosica) in Mu Us Sandy Land were collected and the phosphorus content of different forms were subsequently determined using Jiang-Gu phosphorus fractionation method. The results showed that 1) The total phosphorus (TP) content of Salix psammophila rhizosphere soil was significantly higher than that of other vegetation types while Populus simonii, Amygdalus pedunculata, and Artemisia ordosica increased available phosphorus (AP) content in rhizosphere soil. This indicates that planting Populus simonii and the other 3 vegetation types was beneficial for P activation. 2) The Ca8-P content in rhizosphere soil of Pinus sylvestris, Amygdalus pedunculata, Amorpha fruticosa, and Salix psammophila was lower than in the bulk soil. The decrease in Al-P and Fe-P in Amorpha fruticose rhizosphere soil was the largest, and the difference in Ca10-P content between rhizosphere and bulk soil was the smallest in Salix psammophila. Al-P and Fe-P showed a significant positive correlation with AP in most vegetation rhizosphere soils and were the main forms involved in soil P transformation. This study provides scientific evidence and directives for the management and planting pattern layout of plantations to promote sustainable P management.