• 关键词：稻田  磷素  渗漏淋失  紫色土

• 基金项目：国家科技支撑计划项目(No.2006BAD05B09);国家土壤肥力监测网络和农业部“948”项目(No.2006-Z53)

• 李学平
• 西南大学资源环境学院, 重庆 400716

• 孙燕
• 西南大学资源环境学院, 重庆 400716

• 石孝均
• 西南大学资源环境学院, 重庆 400716

• 摘要：采用原状土壤渗漏计在水稻生育期定期采集不同土壤剖面深度的渗漏水,研究了在不同施磷水平下水稻生育期磷素淋失动态和渗漏淋失量及其对地下水的潜在影响,并分析了土壤Olsen-P含量与磷素渗漏量之间的关系,旨在为紫色土区稻田磷肥的合理施用和控制磷对地下水污染提供科学依据.结果表明,在水稻生长期紫色土的磷素渗漏整体呈下降趋势,前期磷素渗漏淋失量高且变幅较大,在施磷后第5d各土层渗漏水中磷素浓度最高;施肥60d后稻田磷素渗漏淋失负荷显著降低,不同土层和各处理趋于一致.稻田磷素的渗漏淋失受磷肥用量和土壤性质的影响,随着磷肥用量的增加稻田磷的渗漏淋失量增加,3种类型紫色土磷素渗漏淋失量为中性紫色土>钙质紫色土>酸性紫色土.施磷(P₂O₅)90～180kg·hm^-2处理,40cm土层渗漏水中磷的平均浓度在中性、钙质、酸性紫色土上分别为0.13～0.142mg·L^-1、0.097～0.131mg·L^-1和0.083～0.109mg·L^-1,比不施磷处理高33.1%～38.7%、24.7%～44.3%和34.9%～50.4%,在60cm和100cm深处也有相似的特征.3种类型紫色土的土壤Olsen-P含量与磷素渗漏淋失量之间符合指数关系.渗漏水中磷素浓度随土壤剖面深度的增加而降低,淹水种稻初期是磷向下迁移最强和淋失量最高的时期,3种紫色土在施肥后的60d内对地下水质量产生潜在不良影响.整个水稻生育期磷渗漏量较低,最高磷渗漏量为0.262kg·hm^-2.

• Abstract：In this paper,the dynamic loss of phosphorus by leaching was studied by collecting seepage in paddy season from different soil profiles using an in situ soil drainage lysimeter,and analyzing the relationship between soil Olsen-Pand phosphorus loss.The results showed that phosphorus seepage decreased over time,but the amount leached was high and variable at the earlier stages.Concentration of leached phosphorus was the highest in all soil layers 5 d after fertilizing,and remarkably decreased by 60 d after fertilizing.It reached coincidently at all different soil profiles with all treatments.Phosphorus leaching was affected by the phosphorus fertilizer and soil properties.As expected,the amount of Pleached increased with the amount of fertilizer applied.The amount of Pleached decreased in the order neutral soil > calcium soil > acid soil at different profiles in the three kinds of purple soil.The average leaching losses of phosphorus after treatment with phosphorus fertilizer were in the range of 0.13～0.142 mg·L^-1,0.097-0.131 mg·L^-1,and 0.083～0.109 mg·L^-1 in neutral,calcium and acid soil at 40 cm depth,which were 33.1%～38.7%,24.7%～44.3% and 34.9%～50.4% higher than with no fertilization,respectively.Similar results were also obtained at 60 cm and 100 cm depths.Moreover,there was an exponential relationship between Olsen-Pand phosphorus leaching in the three kinds of purple soil.Phosphorus concentration of seepage water decreased with soil depth.In the initial stage of paddy growth,phosphorus moved downward the most and the leaching amount was the highest.In all three purple soils,the seepage of phosphorus could bring potentially unfavorable influence on underground water 60 d after fertilizing.Phosphorus loss was low over the whole paddy season,however,with the highest value = 0.262 kg·hm^-2.

• Key words：paddy field  phosphorus  leakage  purple soil

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