摘要
为研究自然降雨条件下我国西南脆弱岩溶环境区在未受人类活动干扰时土壤元素流失情况,国土资源部岩溶动力学重点实验室于2003年8月5日至7日在广西弄拉岩溶动力系统观测站以表层岩溶泉为介质,通过利用U-20多离子参数仪和CDTP300雨量自动记录仪监测不同降雨强度下泉水中的钾、氮动态变化,来考察土壤钾、氮流失情况及其对泉水水化学的影响。结果表明:在降雨过程中,泉水中的K+和NO-3含量均出现急剧升高的现象,并且泉水内的K+和NO-3含量与降雨强度密切相关。从而说明降雨是导致岩溶区土壤元素流失的主要原因。而泉水内NO3-含量呈现出持续升高的现象,可能是由于岩溶区土壤中氮主要以硝态氮(NO-3-N)形式存在,在降雨停止后的一段时间内仍能通过淋滤作用进入水体。
For understanding soil nutrient loss characteristics under different precipitation at karst area in Southwest China, the Nongla karst dynamic system monitoring site, situated at E 108°19′, N 23°29′, was studied in this paper. Because of the double-layered surface and subsurface structure at karst area, rainfall rapidly penetrates into ground and forms spring or underground water. Therefore, by monitoring the hydrochemieal variation of local spring, the soil nutrient loss characteristics can be known under different precipitation. In accordance with the reason, high-resolution measurements of rainfall, K^+ and NO3^- variation of Landiantang spring were recorded by using data logger with time interval of fifteen minutes from Aug. 5 to Aug. 7 in 2003 at Nongla, Mashan county in Guangxi Province, China, which is scarcely disturbed by man. From the result, it can be seen that the contents of K^+ and NO3^- in Landiantang spring rapidly increased under different precipitation and the content of K^+ and NO3^- in the spring had the positive correlation with the rainfall. According to the result, it can be known that the precipitation is the main factor that leads to the soil nutrient loss at karat area. Moreover, the content of NO3^- in the spring had the different rule from K^+ and continued increase for a long time. The reason is that because of nitrogen mainly existing as NO3^--N in the soil at karst area, the NO3^- still can be lost for a long time undergoing eluviation, even when it stops raining. Therefore, it can be concluded from the result that precipitation not only will bring the problem of nutrient loss at karst area, which will accelerate the process of soil erosion and rock desertification, but also can produce some environmental problems, if presents cultivate at the replenishment region of spring or underground water.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2006年第2期467-470,共4页
Journal of Agro-Environment Science
基金
国家重大基础研究前期研究专项(2002CCA05200)
西南师范大学自然地理学重点学科开放基金资助项目
中国地质科学院重点开放实验室专项资金资助项目
关键词
自然降雨
钾
氮流失
自动化监测
广西弄拉
natural precipitation
loss of phosphorus and nitrogen
hydrochemical data logging
Nongla,Guangxi