| 其他摘要 | This study takes the small catchment of Wangjiazhai peak-cluster depression in Qingzhen, Guizhou Province, a karst plateau area, as the object of study, and uses the carbon and nitrogen stable isotopes of plant as the method of study. Through studies, with the following points drawn: 1) In the process of rocky desertification, the soil structure taking on a development trend of being compacted and viscid. The OM, pH, CEC, C/N values and easy-moving elements in soil drop as the rocky desertification intensifies, and that of hard-moving elements increase. 2) Plants in the area of study is characterized by higher content of Ca, Fe and lower content of P, K, belonging to the Ca > K > Mg type. The difference between species in the content of various elements in plants is all relatively significant. Except for P, K, Fe, Zn, the content gets lower as the rocky desertification intensifies, the element content of plants tends to increase as the growth period gets longer. P is the main restricting factor in the growth of plants in the area of study. 3) In the area of study, common bush plants have foliar δ13C values mainly distributed between -29.5‰ ～ -18.0‰, the difference between species is extremely significant. The foliar δ13C value of plant tends to be positive generally as the rocky desertification intensifies, and negative as the growth period extends. In the area of study, the foliar δ13C value of plant responds more sensitively to the soil environment than to the smaller climate. 4) In the area of study, common bush plants have a foliar δ15N value mainly between -6.08‰ ～ +1.30‰, the difference between species is also extremely significant. The plant foliar δ15N value tends to be more positive as the rocky desertification intensifies. The type and quantity of nitrogen isotopes absorbed by the plant is controlled by its own physiological inheritance and growth and development while subject to the impact of soil, climate, and environmental factors. 5) The foliar δ15N value of plant responds to microhabitat more sensitive than δ13C value. |
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