DENG Yan1、2, HU Yang1、2、3 ,MA Zhu-lu1、2 , ZHU Xing1、2、3, LIANG Xiao1，2、4
( 1. Institute of Karst Geology,CAGS, Guilin 541004, China;
2. Key Laboratory of Karst Ecosystem and Rocky Desertification Treatment, Guilin 541004, China;
3. College of Life Science, Guangxi Normal University, Guilin 541004, China; 4.Guilin University of Technology, Guilin 541004, China)
Abstract：Based on field abservations, the diurnal changes of water potential and weather in Soil-Plant-Atmosphere Continuum(SPAC) in different grades of rocky desertification(RD) (Non RD, light RD, moderate RD, intense RD), Guangxi Autonomous Region, have been studied. Some conclusions have been drawn: atmosphere water potential was sensitive to rocky desertification, and the more serious the rocky desertification, the lower the atmosphere water potential. Plant and soil water potentials in the areas of karst rocky desertification were very low, with the plant water potential varying between -7.79 Mpa and -2.68 Mpa, and the soil water potential between –4.00 Mpa and -0.08 Mpa. The degrees at which the plant was under water stress in the noon are given as follows: intense RD > moderate RD > non RD > light RD. In the case of no rocky desertification, the plant water potential was positively correlated with atmospheric temperature, and it was negatively correlated with relative atmospheric humidity. In light, moderate and intense rocky desertification, the plant water potential was negatively correlated with atmospheric temperature, and it was positively correlated with relative atmospheric humidity. The energy for water circulation in the SPAC system was consumed mostly in the process from plant leaf to atmosphere. The variation order of water potential between leaf and atmosphere was: moderate RD > intense RD > light RD > non RD. The SPAC water potential gradient was increasing along with serious rocky desertification, and at the same time, water cycle and energy change were improved.
Key words: rocky desertification grade; Soil-Plant-Atmosphere Continuum; water potential gradient; karst; Guangxi
EARTH AND ENVIRONMENT Vol. 42, No.2, Tot No.298, 2014, Page 213-220
