Chin J Plant Ecol ›› 2007, Vol. 31 ›› Issue (5): 757-768.DOI: 10.17521/cjpe.2007.0097

• Research Articles • Previous Articles     Next Articles

NUTRIENT DYNAMICS AND HYDROLOGICAL PROCESS OF KARST FORESTS IN MOUNTAINOUS AREA OF CENTRAL GUIZHOU PROVINCE, CHINA

ZHANG Xi1,2(), XUE Jian-Hui2, Kikuo Haibara3, XU Xiao-Tian1,4, TIAN Ye2,3, Hiroto Toda3, LIU Yan-Hui1   

  1. 1Guizhou Provincial Academy of Forestry, Guiyang 550011, China
    2Nanjing Forestry University, Nanjing 210037, China
    3Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan
    4Guizhou University, Guiyang 550001, China
  • Received:2006-09-04 Accepted:2007-01-11 Online:2007-09-04 Published:2007-09-30

Abstract:

Aims Karst forest occurs with limestone soil and humid climate. China's southern karst region is subtropical and centered in Guizhou Province. Precipitation is high and unequally distributed seasonally. Soil drought is frequent as a result of climatic and edaphic factors. Our objectives were to enhance understanding of karst forest ecology and methods of controlling loss of soil and water as a means of managing karst desertification.

Methods For five years, we observed karst natural forest and secondary natural forest in 20 m×20 m plots and analyzed major precipitation ions by ion chromatography. Main indicators were analyzed by Forest Soil Analyzed Methods and observed by Meteorological Observational at Ground Standards.

Important findings Rankings of annual precipitation value regularity were openland > outside karst forest > inside karst forest > under tree and herbaceous layer > runoff at surface and in 90 cm soil > stemflow, and transpiration at forestland and another > total interception in arbuscular and herbaceous layer > total interception in arboreal layer. Annual dynamics of these variables were higher in summer and lower in winter. Maximum water holding capacity ranked soil layer>vegetation, and that in arboreal layer > litter layer > tree layer > herbaceous layer. Ion contents in precipitation had obvious month regularity and decreased in spring and increased in autumn and were high in winter and low in summer. Along precipitation flows (outside forest → in forest → surface runoff → runoff in soil → stream), eight ions were divided into three types: a sustainable rich type included Ca2+ and Mg2+; a surface rich type included K+, Na+, Cl-, N O 3 - and N H 4 + ; and another type included S O 4 2 - . Ions input by precipitation, output by runoff and retained in karst natural forest were higher than that in karst secondary natural forest.

Key words: karst natural forest, karst secondary natural forest, hydrological process, nutrient dynamics