设施菜地土壤pH值、酶活性和氮磷养分含量的变化

    Variations of pH value, enzyme activity and nitrogen phosphorus content in protected vegetable soils

    • 摘要: 为了了解设施菜地土壤的理化性质,测定了日光温室和塑料大棚黄潮土菜地和黑姜土菜地土壤的pH、土壤有机质、氮素、磷素和土壤酶活性含量,结果表明:设施菜地土壤pH值平均每年下降0.05~0.06,15年黄潮土菜地由碱性变为中性,黑姜土菜地由中性变为酸性。设施菜地土壤有机质和全氮含量升高,有机质含量比粮田高11.6%~62.8%。设施菜地土壤硝态氮含量为21.91~49.52 mg/kg,比粮田高13~18倍。设施菜地土壤磷素特别是无机磷积累量大,积累的磷主要分布于耕作层,10年左右菜地土全磷含量比粮田增加1000 mg/kg左右,积累速度约为100 mg/(kg·a),15年黄潮土菜地表层土壤中无机磷积累量为1335.7 mg/kg,有机磷积累量为67.9 mg/kg,二者相差20多倍。设施菜地土壤有效磷含量随种植年限增加而升高,10年左右的菜地土壤有效磷含量一般都在200 mg/kg左右以上,属于极高水平。设施菜地土壤无机磷形态含量变化大,黄潮土菜地Ca8—P、Ca2—P积累量高,黑姜土菜地土壤Al-P和O-P积累量高,黄潮土菜地Ca8—P含量以10年菜地土最大。黄潮土菜地土壤脲酶和碱性磷酸酶活性为黑姜土菜地土的3倍左右,黑姜土菜地土酸性和中性磷酸酶活性为黄潮土菜地土的5倍左右,黄潮土菜地土脲酶、酸性磷酸酶、中性磷酸酶和过氧化氢酶活性高于相临粮田,黑姜土菜地土壤脲酶、中性磷酸酶活性高于粮田,脲酶活性对菜地年龄和菜地类型的反应最敏感。所以设施菜地到一定年限后,土壤性质会发生变化,应采取措施防止土壤酸化,硝态氮,磷素累积。

       

      Abstract: In order to know the basic physical and chemical properties of protected vegetable soils, pH and content of organic matter, nitrogen, phosphorous, enzyme activity in the fluvo-aquic vegetable soil and Heijiang vegetable soils were reported. The results showed that the soil pH value was decreasing at a rate of 0.05-0.06 units per year on average. The fluvo-aquic vegetable soil had been switched from alkaline to neutral soil within 15 years, while the Heijiang vegetable soils had been transformed from neutral to acidic soil. The content of soil organic matter and total nitrogen in vegetable soils was 11.6%~62.8% higher than that of cereal crop soils. NO3-1-N was accumulated in vegetable soils, and the content of nitrate in old vegetable soils was 21.91~49.52 mg/kg and was 13-18 times higher than that in cereal crop soils. Phosphorous especially inorganic phosphorous was accumulated in plow layer. The total P content in 10-year old vegetable soils was 1000 mg/kg higher than that of cereal crop soils. The accumulation rate of P was nearly 100 mg/kg per year. Inorganic P (IP) was accumulated 1335.7 mg/kg in the top soil of 15-year old fluvo-aquic vegetable soil, while organic P was accumulated only 67.9 mg/kg, 20 times less than IP. The content of available P increased with the increase of cultivation years, and in 10-year vegetable soils, the content of available P is above 200 mg/kg, the form and content of IP was varying. The content of Ca8-P and Ca2-P was higher in fluvo-aquic vegetable soils, while Al-P and O-P contents were higher in Heijiang vegetable soils. The content of Ca8-P attained its highest value at 10th year in fluvo-aquic vegetable soil. Enzyme activities of soil urease and alkaline phosphatase were 2 times higher in fluvo-aquic vegetable soils than that in Heijiang vegetable soils. Activities of neutral phosphatase and acidic phosphatase in Heijiang vegetable soils were 4 times higher than that in fluvo-aquic vegetable soils. Catalase activity had nothing to do with soil types. Soil urease, acidic phosphatase, neutral phosphatase and catalase activity in fluvo-aquic vegetable soils were higher than that in cereal crop soils. Soil urease and neutral phosphatase activity in Heijiang vegetable soils were higher than that in cereal crop soil. Soil urease activity was sensitive to vegetable soil age and type. So after a few years of protected cultivation, soil basic properties would change. Measures should be taken to prevent soil acidification, nitrate and phosphorous accumulation

       

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