土地利用方式对陇中黄土高原土壤磷组分的影响

对陇中黄土高原地区至少已有50年传统耕作历史的农田(耕作和休闲)和退耕24年的草地(围封和放牧)土壤磷组分进行了比较研究。结果表明,1)农田土壤中活性无机磷(H₂O-Pi、NaHCO₃-Pi)、潜在活性无机磷(NaOH-Pi)和0～10 cm土层中稳性无机磷(DHCl-Pi)以及30～60 cm土层高稳性无机磷(HHCl-Pi)的含量显著高于草地;潜在活性有机磷(NaOH-Po)含量0～10 cm土层围封草地显著高于农田,20～60 cm土层农田显著高于草地。2)土壤各磷组分之间的迁移转化主要发生在中稳性无机磷DHCl-Pi与其他磷组分之间,且农田中磷组分之间的转化主要发生在0～20 cm土层。3)土壤速效磷、全磷与H₂O-Pi、NaHCO₃-Pi、NaOH-Pi之间及土壤全氮、有机碳与NaOH-Pi、NaOH-Po、HHCl-Pi之间呈极显著正相关关系,而土壤pH与NaHCO₃-Po呈显著负相关,与H₂O-Pi、NaHCO₃-Pi、NaOH-Pi、NaOH-Po、HHCl-Pi极显著负相关。

Effects of land use patterns on soil phosphorus fractions in the Longzhong part of the Loess Plateau

We investigated the soil phosphorus fractions in croplands (planted and fallow, which had a history of traditional cultivation for at least 50 years)and grasslands (fenced and grazed, which had been restored from cultivation for 24 years) on the Loess Plateau. 1) Different land use patterns changed soil phosphorus fractions. The contents of active inorganic phosphorus(H₂O-Pi, NaHCO₃-Pi), potential active inorganic phosphorus(NaOH-Pi), and stable inorganic phosphorus (DHCl-Pi )in the 0-10 cm soil layer and highly stable inorganic phosphorus (HHCl-Pi)in the 30-60 cm soil layer in the croplands were significantly higher than those in the grasslands due to long-term fertilization of the croplands; 2) The conversions between soil phosphorus fractions mainly occured between moderately stable inorganic phosphorus (DHCl-Pi)and other phosphorus components, and also mainly in the 0-20 cm soil layer in the croplands; 3) Available phosphorus and total phosphorus were significantly correlated with H₂O-Pi, NaHCO₃-Pi, and NaOH-Pi. There were significant correlations between total soil nitrogen, soil organic carbon and NaOH-Pi, NaOH-Po, and HHCl-Pi (P<0.01). Soil pH was significantly and negatively correlated with NaHCO₃-Po (P<0.05), H₂O-Pi, NaHCO₃-Pi, NaOH-Pi, NaOH-Po, and HHCl-Pi (P<0.01).