巢湖低丘山区典型植被覆盖类型土壤磷形态分异特征

以巢湖低丘山区为研究对象,分析了该地区5种典型植被覆盖类型表层土壤磷素含量与形态特征及其影响因素.结果表明:次生马尾松林有机碳、总氮、速效氮、总磷与速效磷均高于其他样地,尾矿裸地养分含量为最低,但酸度最大.5种样地0～5、5～10与10～20 cm 3个土层弱吸附态磷(Ex-P)和钙结合态磷(Ca-P)含量均较低,灌木林与次生马尾松林土壤活性态磷[铝结合态磷(Al-P)与铁结合态磷(Fe-P)]含量显著高于其他样地,而惰性态磷[闭蓄态磷(O-P)、钙结合态磷(Ca-P)与残余磷(Res-P)]则以地上群落结构较稳定的草地和次生马尾松林最高,其中5～10 cm土层残余磷(Res-P)含量则以人工恢复林最高.3个土层尾矿裸地各形态磷含量均显示较低水平,但其Fe-P、Al-P含量在总磷中所占比例高于其他样地,所以流失危害大.土层间Ex-P、Al-P、O-P、Ca-P与TP含量均随土层的加深而降低,但Fe-P与Res-P含量在土层间规律不明显.相关分析表明土壤Res-P与其他形态磷间具有显著的正相关关系,“活化磷”,即Ex-P、Fe-P、Al-P三者间也存在显著正相关关系.土壤养分与磷的各种形态显示了良好的正相关关系,但速效磷与O-P、Res-P呈显著负相关关系.

Distribution Characteristics of Soil P as Influenced by Different Vegetation Type in Chao Lake Mountain Areas

Top soil P concentrations and P forms under five typical vegetation types were analyzed in the low mountainous area of Chao Lake. The results indicated that soil of the secondary Masson pine forest had higher contents of soil organic carbon, total nitrogen, available nitrogen, total P and available P. In contrary, mine tails bare land had both lower soil nutrient levels and soil pH values. Among all the five sample lands investigated, the top 20 cm soil was detected extremely low in both Ex-P and Ca-P. Specifically, soil plant available P (Fe-P and Al-P) of the shrub land and secondary Masson pine forest land was significantly higher than other lands while concentration of soil inertial P (O-P, Ca-P and Res-P) was found higher in grassland and secondary Masson forest land, where the place was featured by a stable community structure. A higher Res-P was detected in 5-10 cm soil for the artificial forestlands, while all the three P forms were lower among all soil layers for the mine tails bare lands. However, the ratio of Fe-P and Al-P in total P concentration was the highest in mine tail bare land which indicated the serious erosion occurred. Overall, contents of Ex-P, Al-P, O-P, Ca-P and TP decreased with soil depth increased but no obvious pattern among soil layers. Additionally, a significantly positive correlation occurred between soil Res-P and other soil P forms. Moreover, positive correlation was also detected among soil mineralized P forms, namely, Ex-P, Fe-P and Al-P as well as soil nutrient conditions and soil P forms while negative correlation was observed between available P and O-P as well as Res-P.