旱地和水田土壤DOC吸附-解吸对pH的响应

发布时间：2018-05-23 11:14

本文选题：可溶性有机碳 + 吸附　；参考：《农业现代化研究》2017年03期

【摘要】：为揭示pH对农田土壤DOC吸附-解吸的影响,以亚热带红壤区旱地和水田土壤为研究对象,采用室内模拟实验,对两种土壤添加不同DOC量后分别在pH 4、pH 6和pH 8条件处理下的吸附和解吸试验进行研究,分析不同pH反应条件下土壤对DOC的吸附和解吸过程,并计算土壤对DOC吸附和解吸的参数,探讨DOC吸附和解吸对pH的响应,初步探析吸附对DOC组成的影响。结果表明,同一土壤在pH 4、pH 6和pH 8条件下对DOC的吸附量差异显著(P0.05)。随着DOC初始浓度的增加,在pH 4、pH 6和pH 8条件下旱地土壤对DOC的平均吸附量为4.90、2.98和8.86 mg/g,水田土壤对DOC的平均吸附量为4.12、3.10和8.90 mg/g。土壤DOC吸附方程的拟合效果受到pH的显著影响。吸附平衡后,DOC溶液的单位吸光度值E254、E260、E272和E280(芳香性、疏水性组分)的变化率随pH增加而降低。两种土壤对DOC芳香性、疏水性组分的吸附能力受土壤类型影响较小,但受土壤环境pH的影响显著。两种土壤对DOC的解吸量随pH升高而降低。酸性条件下(pH 4),DOC的净吸附量旱地土壤显著大于水田土壤,但在pH 6和pH 8时两种土壤的净吸附量差异不显著。由于红壤区两种土壤多呈酸性,这可能是造成红壤区旱地和水田土壤DOC含量差异的主要原因之一。
[Abstract]:In order to reveal the effect of pH on the adsorption and desorption of DOC in farmland soil, a laboratory simulation experiment was carried out on the upland and paddy soils in the subtropical red soil region. The adsorption and desorption experiments of two kinds of soils with different amounts of DOC were studied under the conditions of pH 4, pH 6 and pH 8, respectively. The adsorption and desorption of DOC were analyzed under different pH reaction conditions. The parameters of adsorption and desorption of DOC on soil were calculated, the response of DOC adsorption and desorption to pH was discussed, and the effect of adsorption on the composition of DOC was discussed. The results showed that the adsorption capacity of DOC on the same soil under pH 4, pH 6 and pH 8 was significantly different from that of P0.05. With the increase of the initial concentration of DOC, the average adsorption capacity of DOC in dryland soil was 4.90 mg / g and 8.86 mg / g under pH 4, pH 6 and pH 8, and the average adsorption capacity of DOC in paddy soil was 4.12 mg / g and 8.90 mg / g, respectively. The fitting effect of soil DOC adsorption equation was significantly affected by pH. After adsorption equilibrium, the unit absorbance values of DOC solution E254, E260, E272 and E280 (aromatic, hydrophobic components) decreased with the increase of pH. The adsorption ability of the two kinds of soils to DOC aromaticity and hydrophobic component was less affected by soil type, but significantly affected by soil pH. The desorption of DOC from two soils decreased with the increase of pH. The net adsorption capacity of DOC in dry soil was significantly higher than that in paddy soil under acidic conditions, but there was no significant difference between the two soils at pH 6 and pH 8. Because the two soils are mostly acidic in the red soil region, this may be one of the main reasons for the difference of DOC content between the upland and paddy soils in the red soil region.
【作者单位】：广西师范大学生命科学学院;中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室;
【基金】：国家自然科学基金项目(41471199) 国家重点研发计划项目(2016YFD0200106-5)~~
【分类号】：S153

【相似文献】