| 引用本文: | 郭美美,李晓彬,万书勤,等.滨海重度盐渍土加酸滴灌对脱盐过程中土壤pH值的影响[J].灌溉排水学报,2021,(6):72-79. |
| GUO Meimei,LI Xiaobin,WAN Shuqin,,et al.滨海重度盐渍土加酸滴灌对脱盐过程中土壤pH值的影响[J].灌溉排水学报,2021,(6):72-79. |
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| 摘要: |
| 【目的】探索一种低成本、绿色、简便高效的阻控滨海重度盐渍土脱盐过程中pH值升高的方法，研究滴灌加酸处理对滨海重度盐渍土脱盐过程pH值升高的影响。【方法】采用室内土柱模拟试验，设置5种不同加酸用量处理，分别为S1（IWpH=6）、S2（IWpH=6.5）、S3（IWpH=7）、S4（IWpH=7.5）、S5（IWpH=8.2~8.5，不加酸），研究了不同淋洗水量（60、120、180、240 mm）条件下土壤盐度（饱和泥浆提取液电导率ECe）和酸碱度（饱和泥浆提取液pHe）的时空变化特征。【结果】滴灌条件下，首先在滴头正下方形成一个低盐区，随着灌水量的增加，低盐区不断扩大，土壤盐分呈对数函数式降低，不同加酸量处理下土壤盐分淋洗过程和淋洗速率相似。土壤pH值的动态变化过程各不相同，灌水量达到240 mm时，S1—S5处理0~55 cm土层土壤pH均值分别为7.73、7.78、7.86、7.92、7.92，S1—S3处理非盐渍区（<4 dS/m）土壤pH值呈先增加后降低趋势，S4—S5处理的土壤pH值则一直增加，表现出随着加酸量增加，盐分淋洗过程中土壤pH值升高的阶段越短，且回降的越快越低。【结论】当加酸量致灌溉水pH值为6~7之间时，可有效调控滨海重度盐渍土在脱盐过程中出现的pH值升高的现象。因此，建议在滨海盐碱地盐分淋洗过程中，通过滴灌向土壤中添加工业用粗磷酸调节土壤酸碱性，为植物生长营造一个更偏中性的土壤酸碱环境。 |
| 关键词: 滨海盐渍土；土柱模拟；土壤pH值；盐分；淋洗 |
| DOI：10.13522/j.cnki.ggps.2020666 |
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| The Efficacy of Acidified Drip Irrigation for Reducing Soil pH in Remediating Heavy Saline Coastal Soils |
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GUO Meimei, LI Xiaobin, WAN Shuqin, KANG Yaohu
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1. Key Laboratory of Water Cycle and Related Land Surface Processes,Institute of Geographical Sciences and Natural Resources Research, CAS, Beijing 100101, China;
2. College of Resources and Environment, University of Chinese Academy of Sciences, UCAS, Beijing 100049, China
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| Abstract: |
| 【Background】Heavy saline coastal soil is a valuable land resource but its high salt content and sticky texture, along with its high sodium adsorption ratio and shallow groundwater table, makes it difficult to remediate. Previous studies had shown that the pH of coastal saline soil increased during its remediation, which could alter physical, chemical and microbiological properties of the soil for crops to grow. Common methods to alleviate these side effects include application of organic fertilizers, desulfurized gypsum, biochar and other additives. But they are expensive and not applicable to large-scale soil remediation. As such, more efficient methods are needed.【Objective】The aim of this paper is to present a simple and low-cost, yet green and efficient method to control soil pH in remediating heavy saline coastal soils by acidifying the drip irrigation water.【Method】The experiment was conducted in laboratory columns. It consisted of five treatments with the irrigation water pH controlled at 6 (S1), 6.5(S2), 7(S3), 7.5(S4) respectively. Without acidification (pH 8.2~8.5) was taken as the control (CK). In each treatment, we measured spatiotemporal variation in electrical conductivity of the saturated soil paste (EC), and its associated pH after the soil was leached by 60 mm, 120 mm, 180 mm and 240 mm of water respectively.【Result】Desalination occurred in the soil below the emitter first and it then expanded gradually; soil salinity decreased logarithmically with the amount of irrigation water. In all treatments, the temporal changes in salt leaching pattern and leaching rate were similar, while the change in soil pH differed. After 240 mm of water was applied, the average soil pH in 0~55 cm of soil under S1—S5 treatment was 7.73, 7.78, 7.86, 7.92, 7.92, respectively. Soil pH in the non-saline area (<4 dS/m) in S1—S3 treatment increased first followed by a decline, while the pH in S4—S5 treatment continued to increase, as time elapsed. It was found that the change in soil pH depended on acidity of the irrigation water.; the lower the pH of the irrigation water was, the sooner it took the soil pH to peak, and faster for it to fall back to constant.【Conclusion】Acidifying drip irrigation water to a pH in the range of 6~7 was effective to avoid soil pH increase during remediating heavy saline coastal soil. This can be achieved by adding industrial phosphoric acid to the irrigation water to create a suitable soil environment for plants to grow during the remediating processes while in the meantime controlling the soil pH not exceeding a critical value. |
| Key words: saline coastal saline soil; column experiment; soil pH; salt leaching |
