南京林业大学学报(自然科学版) ›› 2019, Vol. 43 ›› Issue (04): 178-184.doi: 10.3969/j.issn.1000-2006.201801030

• 研究简报 • 上一篇    下一篇

次生落叶阔叶林降雨过程中的4种金属元素特征

张 楠1,2,范春楠1,陈思羽3,郑金萍1*,郭忠玲1*   

  1. (1.北华大学林学院,吉林 吉林 132013; 2.杭州富晟市政交通设计有限公司,浙江 杭州 311400; 3.吉林省林业科学研究院,吉林 长春 130033)
  • 出版日期:2019-07-22 发布日期:2019-07-22
  • 基金资助:
    收稿日期:2018-01-17 修回日期:2019-04-15 基金项目:国家自然科学基金项目(31370622)。 第一作者:张楠(1002100049@qq.com),ORCID(0000-0001-6875-6742)。*通信作者:郑金萍(zhengjinping80@126.com),副教授,负责指导论文写作与修改,ORCID(0000-0001-7738-2981); 郭忠玲(gzl65@163.com),教授,负责指导试验布置与设计,ORCID(0000-0002-2088-5745)。

Effects of precipitation characteristics on the distribution of four metal elements by rainfalls in a secondary deciduous broad-leaved forest

ZHANG Nan1,2, FAN Chunnan1, CHEN Siyu3, ZHENG Jinping1*, GUO Zhongling1*   

  1. (1.Forestry College, Beihua University, Jilin 132013, China; 2.Fucheng Municipal Traffic Design Co., Ltd., Hangzhou 311400, China; 3. Jilin Academy of Forestry Science, Changchun 130033, China)
  • Online:2019-07-22 Published:2019-07-22

摘要: 【目的】通过长期野外定点、定位法,监测次生落叶阔叶林森林生态系统降雨再分配过程,检测其中金属元素Ca、K、Fe、Cu含量,探索降雨驱动下的森林养分循环特征,为提升森林经营管理水平提供参考。【方法】在研究地1 340 m2径流场内的35 m气象观测塔上,安装4台翻斗式自记雨量计(HOBO),对降雨情况自动连续监测,共获得次生落叶阔叶林生长季的24场大气降雨量和降雨历时数据; 在距研究地约500 m的楼顶上,设置6个标准雨量筒,用于采集大气降雨样品; 以梅花布点法在径流场内,设置了5个受雨器,收集穿透雨样品; 利用聚乙烯管制作茎流环环绕标准木,连接盛水器采集树干茎流水样; 在径流场梯形围堰的出水口蓄水池中,采集土壤表层地表径流水样。水样的采集量约250 mL,利用水质悬浮物重量法、水质pH玻璃电极法分别测定悬浮物(SS)含量和pH,利用电感耦合等离子发射光谱法(ICP-AES)测定水样中金属元素Ca、K、Fe、Cu含量。【结果】①大气降雨中输入4种金属元素的质量浓度以6月最高,9月最低,呈先增后降的变化趋势。Fe质量浓度月变化最大,Ca最小。②森林对降雨再分配后,经穿透雨后除Cu外各金属元素质量浓度均有增幅; 除Fe外各金属元素质量浓度均为6月最高; 各元素质量浓度的月变化以Fe为最大,Ca最小。③经树干茎流后,4种金属元素质量浓度均有所增加,且明显高于穿透雨,以K淋溶系数最大,Cu最小。但各金属元素质量浓度的月动态不一,总体表现为夏季偏高、秋季偏低的特征,以Cu的月波动最大,Ca的最小。④降雨过程中4种金属元素的质量浓度变化,主要与SS、降雨pH、降雨量、降雨类型、降雨历时、降雨强度等因素有关,大多表现为随降雨量、降雨强度和降雨历时增加而减少的趋势,其中Ca受降雨量的影响显著,K与降雨pH显著正相关,Cu与Fe主要源于降雨淋洗的悬浮物。不同降雨类型对Fe迁移影响不显著,小雨对Ca、K迁移影响显著,暴雨对Cu迁移影响显著。⑤大气降雨净输入量Ca、K、Fe均为正值,Cu为负值,净迁移量中4种金属元素均为负值。【结论】受降雨特征等因素影响,次生落叶阔叶林生态系统对Ca、K、Fe、Cu元素的淋溶与吸存能力表现出不同的迁移特征,明确在降雨驱动下该森林生态系统金属元素的动态过程,可为次生林养分循环、植物生长发育、生态水文调节及森林经营等领域提供重要依据。

Abstract: 【Objective】Investigate how different rainfall characteristics influence the redistribution of nutrient elements within a secondary deciduous broad-leaved forest ecosystem. The results will provide a theoretical basis for the improvement of forest management level. Precipitation samples were collected from long-term fixed-point sampling plots in the field, and the concentrations of elements Ca, K, Fe and Cu in the samples were determined. 【Method】 The study was conducted in a 1 340 m2 field runoff study site with four dumping-type self-recording rain gauges(HOBO)installed on observation towers 35 m above the ground. The amount and duration of 24 separate rainfall episodes were automatically recorded during the growing season in the secondary deciduous broad-leaved forest. Six parallel standard rain gauges were set up on the roofs of buildings within 500 m from the study site to collect precipitation samples. Five rain absorbers were set up in the study site at spots with suitable canopy coverage and in a plum-blossom pattern to collect throughfall water. Stemflow was collected using polyethylene stemflow rings mounted on standard stems and connected to a water container. Surface runoff water samples were collected from a reservoir at the trapezoidal outlet of the study site. The water samples were around 250 mL. The suspended solids(SS)content and pH of each sample were determined using the water suspension weight method and a pH electrode, respectively, and the concentrations of Ca, K, Fe and Cu in the water sample were determined using inductively coupled plasma emission spectroscopy(ICP-AES). 【Result】 ① Outside the forest, the input of concentrations of the four metal elements in precipitations were the highest in June, and lowest in September. The concentrations of metal elements tended to increase initially and then decrease over each month. Monthly variation was largest for Fe and smallest for Ca. ② After the redistribution of precipitation in the forest, the concentrations of various metal elements in the throughfall changed. After leaching by throughfall, the concentration of each metal element increased, except for Cu. In addition to Fe, the concentrations of other metal elements in the throughfall were also the highest in June, while the monthly variation of Fe in the throughfall was also the largest, and the average concentration in June was higher than the annual average, and monthly changes of Ca were still minimal. ③ After leaching by stem flow, the concentrations of the metal elements increased, and were higher than those in the throughfall. During the precipitation distribution process, the leaching coefficient was the largest for K and smallest for Cu. However, the concentration of each metal element in the stemflow varied, and the overall trend was characterized as high in the summer and low in the autumn. The monthly changes of Cu concentration were the largest, and those of Ca were the smallest.

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