摘要
以不同林龄(10 a、22 a、34 a)杉木人工林为研究对象,测定其凋落物及土壤中有机酸的组成,比较不同林龄杉木林土壤酸度及不同形态磷的含量,分析杉木凋落物源有机酸对土壤磷有效性的影响。结果表明,在杉木凋落物中检测到草酸、丙二酸、苹果酸、反丁烯二酸、丁二酸及柠檬酸等6种低分子有机酸。其中,草酸含量最大,且凋落叶的有机酸含量最高。不同林龄杉木凋落物的有机酸含量表现为:34 a>22 a>10 a。在土壤中,仅检测到草酸这一凋落物源有机酸的优势有机酸,而不同林龄杉木林的土壤有机酸含量与凋落物一致,也随着林龄的增加而增加,并随着土层加深而减少。因土壤有机酸的存在,不同林龄杉木林土壤存在明显的酸化现象,且林龄越大pH值越低。土壤有效磷与有机酸变化规律一致,表现为:34 a>22 a>10 a,且随土层加深逐渐减少。O-P、Fe-P、Al-P与Ca-P等无机磷则反之,呈现10 a>22 a>34 a的变化规律。可见,不同林龄杉木林中土壤有机酸(主要是草酸)能降低土壤pH值,且有效促进土壤磷的活化,致使土壤有效磷含量的增加,而凋落物源有机酸是土壤有机酸的重要来源之一,对土壤磷有效性的提高起着重要作用。
In this study, the composition and content of organic acids were determined in different litters and soil of Chinese fir plantations at different ages （10 a, 22 a, 34a）. We also determined the pH value of soil and the distribution of available phosphorus （P） and inorganic P, and analyzed the influence of organi cacids derived from litters on the availability of soil P.Results showed that six low molecular organic acids were detected in the litters, including oxalic acid, malonic acid, malic acid, fumaric acid, succinic acidand citric acid. The content of oxalic acid was greater than other organica cids obviously, and organic acid content in leaf litter was the highest. The organic acid content in the litter was in the sequence of 34 a 〉 22 a 〉 10 a. Oxalic acid was detected in the soil of different forest only. And the organic acid content in soil showed the same change pattern with that in the litters. Soil showed obvious acid ification due to the organic acids accumulation in soil of different forests, and the value of soil pH decreased with the forest age. Available P also showed the completely consistent change with organi cacids in soil of different forests. However, inorganic P in soil such as O-P,Fe-P,A1-P and Ca-P decreased in the order of 10 a 〉 22a 〉 34 a. In conclusion, organic acids in soil can reduce soil pH value and effectively promote availablily of P in Chinese fir plantations. Additionally, organi cacids derived from litter was an important source of those in soil and played an important role in the improvement of soil P availability.
出处
《土壤通报》
CAS
北大核心
2017年第5期1154-1161,共8页
Chinese Journal of Soil Science
基金
国家科技支撑计划课题(2015BAD09B010102)
"十三五"国家重点研发计划项目(2016YFD0600301)资助
关键词
不同林龄
凋落物有机酸
土壤有机酸
有效磷
无机磷
Forests at different ages
Organic acids derived from litters
Organic acids in soil
Available phosphorus
Inorganic phosphorus
