典型黑土区不同水土保持林表层土壤磷素形态及有效性

以典型黑土区人工营造的落叶松林、水曲柳林、樟子松林和美青杨林表层土壤(0～10 cm)为对象,研究不同类型水土保持林土壤磷素的形态和有效性.结果表明: 水曲柳林和美青杨林土壤全磷、速效磷和磷各组分含量均显著高于落叶松林和樟子松林;4种林地土壤磷主要以有机磷形式存在,并且中活性有机磷NaOH P_o含量最高,占土壤磷素总量的58.9%;对植物有效性相对较高的H₂O P_i和NaHCO₃ P含量较低,分别占土壤磷素总量的1.2%和6.6%;除NaHCO₃ P_o外,土壤中不同磷素形态之间以及磷各组分与土壤有机质、全磷和有效磷之间具有显著相关关系.表明研究区内阔叶林比针叶林能够显著地提高土壤磷的有效性.

Topsoil phosphorus forms and availability of different soil and water conservation plantations in typical black soil region,Northeast China.

Aiming to understand soil phosphorus status of plantations in typical black soil region of Northeast China, the topsoil (0-10 cm) phosphorus fractionations and its availability were exa mined in four soil and water conservation plantations dominantly composed of Larix gmelini, Fraxinus mandshurica, Pinus sylvestris var. mongolica and Populus nigra var. italica × P. cathayan, respectively. The results showed that total P, Olsen P and the concentration of different P fractionations in F. mandshurica and P. nigra var. italica × P. cathayan plantations were significantly higher than that of the other two coniferous plantations. Organic P was the major fractionation in the four plantations’ topsoil, and sodium hydroxide extractable organic P (NaOH P_o) representing moderately
labile organic phosphorus was predominant, which accounted for 58.9% of total P. The contents of H₂O P_i and NaHCO₃ P which were more labile to plant were lower, only accounting for 1.2% and 6.6% of total P, respectively. Except for NaHCO₃ P_o, all the other P fractions of four plantations correlated with each other, and they also had significant correlations with soil organic matter, total P, Olsen P. Compared with the coniferous plantations, the broadleaf plantations presented higher availability of phosphorus.