摘要
为探讨酸雨对粤北岩溶区岩溶土壤中Ca迁移和流失的影响,选择酸雨频率和酸雨程度较高的我国广东省佛山市,开展自然降雨对红色石灰土壤中Ca^(2+)的流失影响试验,于2011—2013年共收集到61次有效降雨产生的渗漏液,分析渗漏液中ρ(Ca^(2+))的变化情况,并间隔0.5 a左右测定供试土壤中的w(水溶性Ca)和w(TCa)(TCa为全钙),将试验3 a后供试土壤的w(有机质)、w(TN)、p H与供试源地土壤进行比较.结果表明:1单位降雨造成的红色石灰土壤中Ca^(2+)流失量与渗漏液中ρ(Ca^(2+))呈极显著正相关,与降雨量、渗漏液p H均呈正相关,而与雨水p H呈负相关,但不显著;单位降雨造成的土壤Ca^(2+)净流失量达到2.16×10-5g/(mm·kg),61次有效降雨造成的Ca^(2+)净流失总量为0.05 g/kg.2与蒸馏水及石灰岩采样点所在的坡麓洼地积水比较,酸雨明显增加了红色石灰土壤Ca^(2+)流失量,但其影响因素复杂.p H为4.50~<5.65的轻度酸雨造成的土壤Ca^(2+)流失量最大,其次是p H为5.65~6.29的非酸雨和p H<4.50的重度酸雨.3降雨使石灰土壤中的w(TCa)呈持续减少趋势,2011—2013年供试石灰土壤中w(水溶性Ca)减少量为0.36 g/kg,并且呈明显的由上至下的减少迁移过程.4与供试源地土壤相比,历经3 a酸雨淋溶的红色石灰土壤的w(有机质)和w(TN)均极显著增加,表层p H也极显著升高,意味着酸雨加速了土壤的分解转化,存在潜在的养分流失风险.研究显示,酸雨不仅造成石灰土壤中Ca^(2+)的加速流失和迁移,也加速了土壤中各类养分的分解转化,同时还会对岩溶地形、岩溶植物、流域水环境产生潜在或直接的影响.
The severity of acid rain in the northern part of Guangdong Province,China,has deteriorated due to rapid urbanization and industrial transfer in recent years. The effects of acid rain on the processes of karst soil calcium ion migration and regional eco-environment have not been investigated. A three-year experimental study was conducted to assess the effects of rainfall events on the migration and loss of water-soluble calcium ions（ Ca-（2＋）） from terra rossa in a karst area where acid rain occurs at high frequency and high severity. Soil leachate was collected and analyzed after 61 events of effective rainfall（ 100 m L leachate） from 2011 to 2013. The content of Ca-（2＋）in the soil samples was examined each half year for three years. The experimental soil samples＇ soil organic matter（ SOM）,total nitrogen（ TN） and p H were compared with control samples after three years. The results showed that： 1） Net Ca-（2＋）loss from the soil by a single rainfall was positively correlated with leachate Ca-（2＋）and rainfall,while rainwater p H value was negatively correlated with leachate Ca-（2＋）;per unit（ mm） rainfall led to a Ca-（2＋）loss of 2. 16 × 10- 5g/（ mm·kg） from the soil. Cumulative net Ca-（2＋）loss from the soil by 61 events of effective rainfall was 0. 05 g/kg. 2） In terms of per unit rainfall,the largest net Ca-（2＋）loss from the soil occurred with mild acid rain（ p H 4. 50- 5. 65）,followed by non-acid rain（ p H5. 65-6. 29） and severe acid rain（ p H 4. 50）. Net Ca-（2＋）losses by natural rainfalls of acid rain were significantly greater than those by simulated rainfalls of distilled water（ control） and byrainwater from the karst depression area of a talus slope（ soil sampling area）. 3） Total Ca content in the soil continuously decreased over time due to acid rain,with a total reduction of 0. 36 g/kg and an annual loss of 0. 12 g/（ kg·a）. 4） Compared with the control samples,w（ SOM）,w（ TN） and top soil p H of the experimental red lime soil samples,which had been leached by acid rain for three years,were significantly increased. This meant that acid rain accelerated the soil decomposition and transformation,and brought potential nutrients losses. Acid rain not only causes the loss and migration of calcium irons in soil,but also accelerates the soil degradation. Furthermore,it will affect the topography,vegetation species and the water environment of the Karst area.
出处
《环境科学研究》
EI
CAS
CSSCI
CSCD
北大核心
2016年第5期737-745,共9页
Research of Environmental Sciences
基金
国家自然科学基金项目(31170486
41571091)
中国科学院框架服务网络计划(STS计划)项目(KFJ-EW-STS-092)
