灌水对不同次生盐渍化水平设施土壤氮、磷迁移特征的影响

Effect of Irrigation on Characteristics of Nitrogen and Phosphorus Eluviation in Greenhouse Soil with Different Levels of Secondary Salinization

通过野外调查与室内土柱模拟试验相结合的方法,对灌水条件下不同次生盐渍化水平设施土壤氮、磷含量的变化及迁移特征进行研究。结果表明:(1)灌水后土壤水分变化主要集中于20cm以上土层,灌水后13～15d,不同次生盐渍化程度的土壤水分都表现出向下迁移的特征。(2)设施土壤硝态氮含量最高值均出现在土层20cm处,且次生盐渍化程度越严重,硝态氮表聚现象越为突出。灌水15d后,各处理铵态氮集中分布于20-40cm土层,灌水后土壤铵态氮含量变化不明显,环境风险较小。(3)设施土壤速效磷含量高于露地土壤,且表层土壤速效磷含量介于40～60mg/kg之间,灌水后各时期不同次生盐渍化程度土壤剖面中速效磷的分布趋势基本一致,虽受灌水的影响较小,但存在潜在的环境风险。

Based on field investigation and soil column simulated experiments, effect of irrigation on characteristics of nitrogen and phosphorus eluviation in different level of secondary salinization in greenhouse soil was conducted. The results showed that soil moisture variation of different treatments mainly concentrated in top soil layer（~20 cm）. The soil moisture characteristics of different secondary salinization had shown a downward migration from 13 d to 15 d after irrigation. The highest value of nitrate nitrogen in greenhouse soil was observed in soil layer of 20 cm, nitrate nitrogen content in the top soil layer was increased with increasing degree of secondary salinizatiom Ammonium nitrogen mainly concentrated in the soil layer from 20 cm to 40 cm under different treatments after 15 d irrigation. It changed insignificantly with low environmental risk after irrigation. Available phosphorus content in greenhouse soil was greater than contrast bare ground, the content of available phosphorus varied from 40 mg/kg to 60 mg/kg in top soil layer. Distribution of available phosphorus had the same trend in soil profile after irrigation under different treatments. There was a potential environmental risk though available P was less influenced by irrigation.