长期施肥对潮菜地土壤磷素积累和无机磷组分含量的影响

Effect of Long-term Fertilization on Phosphorus Accumulation and Inorganic Phosphorus Fractions Content in Vegetable Soils

以在潮土上形成的菜地土壤为材料,研究了菜地土壤全磷、有机磷、有效磷、无机磷组分含量变化及其土体分布特征,结果表明：潮菜地土壤磷素积累量大、积累速度快,10年左右的菜地土耕层全磷含量增加1000mg/kg左右,积累速度约100mg/（kg·a）。菜地土壤积累的磷主要是无机磷,0-20cm土层中无机磷含量占土壤磷素总量的90%以上,菜地土壤有机磷积累数量较少,其含量为130-190mg/kg。菜地土壤磷素主要分布于0-20cm耕作层中,其含量一般为0-80cm土体磷素总量的50%。与起源土壤相比,菜地土壤中下部土层也有磷素积累现象,种菜时间越长,其积累量越多,特别是有机磷在菜地土壤中有较明显的淋溶特征。菜地土壤无机磷组分与起源土壤相比变化很大,潮菜地土无机磷组分以Ca8—P、Ca10—P、Ca2—P和O—P为主,与起源土壤相比,Ca8—P、Ca2—P和Al—P含量增加最多,Ca10—P含量仅有微量增加。菜地土壤有效磷含量普遍很高,10年左右的典型菜地耕层土壤有效磷含量为200mg/kg左右,有效磷在菜地土体中呈典型的“丁”字形分布。

This paper reported the content of total phosphorus phosphorus （Pi） fractions in vegetable soils. The results showed （P）, that organic P, available P, and inorganic the total P content in 10-year greenhouse vegetable soils was 1000 mg/kg higher than that of cereal crop soils. The accumulation rate of total P was nearly 100mgP/kg per year. The main P form accumulated in the vegetable soils was Pi, which was above 90% of the total P, while organic P content was 170mg/kg.Most of the P accumulated in vegetable soils was distributed in plough layer （0-20 cm in depth）. But compared with the cereal crop soils, P accumulation was observed in middle and subsoil in vegetable soils. It is especially that organic phosphorus showed relatively serious leaching characteristics. Pi in fluvo-aquic vegetable soils was mainly Cas-P, Ca10-P, Ca2-P and O-P, and the contents of Cas-P, Ca2-P ,A1-P increased much more and Calo-P increased slightly. Most of Ca2-P and Ca8-P accumulated in plough layer soil, and 70% of the total amount of the Pi fractions accumulated in 0-80 cm in depth in soil profile. Available P content in typical old vegetable soils was about 200mg/ kg ,and decreased with the depth in soil profile.