自然资源部岩岩溶动力学重点实验室

典型岩溶泉流域不同土地利用方式土壤营养元素形态及其影响因素

2009-08-15KDL 2378

Speciation of Soil Nutrient Elements and Their Controll ing Factors in Different Landuses of Typical Karst Spring Watershed
[Abstract]  Taking two spring basins at different elevation (Bitan and Shuifang ) in Jinfo Mountain of Chongqing as an example , the author discussed the soil p hysical-chemical properties , soil environmental quality in soil at the depth of 0 - 20 cm and 20 - 40 cm respectively and their driving factors , including pH value , organic matter , the total contents of elements (Ca , Mg , Cu , Zn , Mn) and the available species contents in woodland , bush , grassland and tilled land. The results of total and available content s of major elements in different landuses showed spatial heterogeneity in karst region. Maximum values of Calcium (Ca)and magnesium(Mg) are located at woodland of Shuifang and grassland of Bitan respectively , controlled by lithology. Both total and available contents of Ca in bottom soil layer are greater than those in surface layer ,which indicate downward eluviation is more important for karst soil Ca than biological processes. Available Mg content of Bitan account for 10 % of total , whereas 2% in Shuifang , and less than the average exchange Mg concent ration of 4 % of southern China soil . Furthermore , high Ca or Mg amount in soil seems to show a inhibitory effect on available contents of copper (Cu) , zinc (Zn) and Manganese (Mn) , t hat is to say , soil with relative low Ca and Mg amount always has higher available contents of Cu , Zn , Mn. Under the same landuse pattern , soil nutritions content at Shuifang are greater than that of Bitan. Surface soil hydrolytic nit rogen of woodland at Shuifang spring reaches 1496. 73 mg/ kg , almost 5 times of t hat at Bitan , t he former’s organic matter is 23. 61 % , 7 times of latter . It indicates that soil under forest can maintain a high level of organic matter in karst region , and Ca2 + loss in soil may cause a remarkable decrease of organic matter . With the vegetation degradation , i. e. intensify of human activities , soil nut rition contents decrease from woodland,bush,grass to tilled land. The content also decreases in soil profile from surface layer to bottom layer , with different magnitude : hydrolytic nitrogen > effective potassium > effective Phosphorus.
[Key words]  landuse ; Karst soil ; element species ; Jinfo Mt of Chongqing
[摘   要]   对金佛山典型岩溶泉流域不同土地利用下土壤分层取样,并现场测试土壤水分,室内测试分析其营养元素形态含量,论述了土壤营养元素形态含量差异、分布特征以及影响它们分布的因素。结果表明,不同土地利用之间土壤主要元素全量及其有效态含量差异明显,反映了岩溶区土壤的空间异质性。钙含量最高为水房泉林地,镁含量最高为碧潭泉草地,受岩性的控制。无论是全量还是有效态,Ca 含量在下层的含量明显高于表层,说明对岩溶区土壤Ca 而言,淋溶作用似乎强于生物作用。高钙或高镁似乎对铜锌锰有效态有抑制作用,低钙和低镁土壤可以保持较高含量的铜锌锰有效态含量。在原始林地条件下,土壤可保持较高的有机碳(质) 含量,钙的流失可能是土壤有机碳含量下降的主要因素。随着植被的退化,从林地、灌草丛到耕地,土壤养分含量减小,即人类活动程度的增加,土壤养分逐渐流失。土壤剖面上养分含量从林灌、草地到耕地,减小幅度有逐渐增大趋势,也就是说植被破坏的结果可导致土壤养分的快速流失。
[关键词]  土地利用;岩溶土壤;元素形态;重庆金佛山

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