咸水淋洗对广东大万山岛土壤理化性质影响的研究

海水对海岛土壤理化性质的影响不容忽视,但目前对南方海岛土壤的盐胁迫效果研究仍不多见。为了研究海岛工程建设运行过程中海水盐分对土壤的胁迫作用所导致的土壤环境问题,选取广东大万山岛土壤,利用土柱淋溶和ICP-AES测定方法,以质量分数为0、1%、3%、5%、7%的Na Cl溶液作为淋溶的盐溶液,研究了咸水淋洗对土壤理化性质的影响。大万山岛土壤阳离子交换量为2. 68 cmol+/kg,有机质质量比为51. 71 g/kg,p H值为4. 99,电导率为49. 4μS/cm。结果表明,随淋洗液中盐质量分数增加,土壤淋出液的p H值逐渐降低,淋出的Ca、Mg累积量逐渐增加。当淋洗液盐质量分数从0逐渐升高至7%时,土壤淋出的Ca、Mg累积量分别从2. 63 mg/kg和1. 02 mg/kg上升到218. 82mg/kg和51. 29 mg/kg。在不同质量分数盐淋洗液淋洗后,土壤的阳离子交换容量发生显著变化。土壤的有机质质量比在不同质量分数盐淋洗液的淋洗下大大降低,当淋洗液的盐质量分数为7%时,土壤有机质质量比仅为9. 61 g/kg。由此可以判断,咸水淋洗对广东大万山岛土壤产生了负面影响。

Effect of the salt water leaching on the physico-chemical properties of the soil of Wanshan Islands,Guangdong

The main purpose of this paper is to study and relieve the effects of the salt water of the marine environmental problems caused by the construction and operation of the island projects,and provide scientific basis for the effects of project construction and operation on the soil.The physico-chemical properties of the island soil ought to be greatly affected by the seawater,but the research in this way remains still at the stage of infancy in China.With the soil sample in the Wanshan Islands under Zhuhai administration,Guangdong,we have been engaged in investigating and identifying the effect of the salt water leaching on the island with the method of soil column leaching and inductively coupled plasma-atomic emission spectrometry testing for a long time.By taking the different Na Cl solution samples with the mass fraction ratios of 0,1%,3%,5%and 7%as the leaching solutions,respectively,we have traced and determined the physicochemical properties of the island soil as shown in the following ways:the soil cation exchange capacity:2.68 cmol+/kg;the soil organic content rate:51.71 g/kg;the p H value:4.99;and,the soil conductivity:49.4μS/cm.Our experimental results indicate that the p H value of the soil leached solution tends to decrease but the loss accumulation rates of Ca and Mg in it have been found increasing with the increase of the salt concentration rate in the leacheate.And,the loss accumulation rates of Ca and Mg in it are equal to 2.63 mg/kg and 1.02 mg/kg by taking the leacheate with 0%Na Cl solution,accordingly.Moreover,the loss accumulation rates of Ca and Mg in it account for218.82 mg/kg and 51.29 mg/kg,accordingly,by using the leacheate with 7%of Na Cl solution,though the soil cation exchange capacity tends to change greatly with the leaching of salt.And,comparatively,the soil organic content rate can be significantly decreased with the increase of the salt concentration rates in the leacheate from 0 to 7%,but the low soil organic content rate can reach 9.61 g/kg when Na Cl solution began to leach at a rate of 7%.Thus,it can be concluded that the saltwater leaching may have a negative effect on the soil of the said islands.Hence,the results gained by our study should be highly valuable for the soil and ecosystem protection in the area of Wanshan Islands in Guangdong.