| Rocky desertification is an extreme form of land degradation which is restricting the development of economy and social stability in the rocky desertification areas in China,and the basic theory and technology of the vegetation restoration is one of the main problems in the comprehensive alleviates of rocky desertification.This research was conducted at light?LRD?,moderate?MRD,abandoned land?and intense?IRD?rocky desertification shrub ecosystems in Shaoyang,Hunan province.We investigated the diversity of the three plots,collected common plants as well as soil of three layers?0-15,15-30,30-45 cm?.We studied on plant diversity,the physical and chemical properties of soil,and the content of calcium in plants,and analysis the high calcium adaptation of plants in rocky desertification area,aimed at providing theoretical and technical support for the vegetation restoration in rocky desertification area.The results are as follows:?1?Characteristics of plant communities in rocky desertification area in Southwest Hunan.81 species plants that belonging to 38 families and 66 genera,have appeared in the rocky desertification of Southwestern Hunan.40 species appeared in LRD,55 in MRD and 47 in IRD.The diversity of plant species in MRD were higher than that of LRD and IRD.There were 18 shrubs and 8 herbaceous plants whose important value???were beyong 1 in the rocky desertification.Among the 3 plots,the IV of herbaceous were higher than that of shrubs,the IV of Miscanthus sinensis were the highest,35.62 and 33.05 in LRD and IRD respectively,and in MRD the IV of Dendranthema indicum was 17.41,which is the highest.The IV of Indigofera tinctoria,Castanea henryi,Pyracantha fortuneana,Serissa japonica,Vitex negundo and Abelia chinensis in shrub plants,Miscanthus sinensis,Artemisia carvifolia,Sanguisorba officinalis,Themeda japonica in herbaceous plants were beyond 1 in three plots.?2?In the LRD and MRD,the soil texture is clay,and in IRD the soil is silty clay or loam.With the process of rocky desertification,clay content decreased,sand and silt content increased gradually,the soil bulk density increased and total porosity,capillary porosity and capillary moisture decreased.The soil of rocky desertification was of weak acidity,and the pH value of soil increased gradually with the grade of rocky desertification.The soil organic matter and total N,total P content showed the order,MRD>LRD>IRD,the content showed the order,MRD>IRD>LRD,the content of soil organic matter and total N were higher than that below 15cm significantly;and for total P and total K,there was no obvious difference between different soil layers.The content of total N was positively correlated with the content of organic matter and total P,and the content of total K was negatively correlated with the content of organic matter.Soil bulk density and soil organic matter and N content showed a significant negative correlation;soil total porosity,capillary porosity,capillary moisture were positively correlated with soil nutrient content;no significant correlation between the soil physical properties and the content of total P.?3?The characteristics of calcium content in soil.The content of total calcium of soil in rocky desertification area in Southwest Hunan was 2.40 g·kg-1,exchangeable calcium content of soil was 1.46 g·kg-1,with the development of rocky desertification,total calcium and exchangeable calcium content of soil increased significantly.Both total calcium and exchangeable calcium content have no significant difference between different soil layers,and both of them have a significant positive correlation with soil pH value.?4?The characteristics of calcium content in plants and high adaptation of common plants in rocky desertification area.The calcium content of the part abovegroung of 41 common plants were 19.67 g·kg-1,the calcium content of underground parts were 10.79 g·kg-1.The aboveground parts of the plants were significantly higher than those of underground parts in the 3 rocky desertification plots,but there was no significant difference among different rocky desertification plots.The calcium content of the abovegroung part of nitrogen-fixing plants was higher than that of non-nitrogen-fixing plants,while the content of calcium was lower than that of non-nitrogen-fixing plants in underground parts,the difference was not significant.The calcium content of aboveground and underground parts of dicotyledon and C3 plants were significantly higher than that of monocotyledon and C4 plants.Between the different life form plant,the content of aboveground and underground differed significantly,the calcium content of shrub plants were significantly higher than that of the herbs.The aboveground and underground parts of Sanguisorba officinalis,the underground parts of Castanea henryi and Dendranthema indicum,the aboveground parts of Themeda japonica have significant correlations with the content of soil exchangeable calcium among the 19 species that appeared in three plots.While the others were not.Sanguisorba officinalis,Themeda japonica,Castanea henryi and Dendranthema indicum are calcium-indifferent plants,Abelia chinensis,Loropetalum chinense,Glochidion puberum,Serissa japonica,Indigofera tinctoria,Aster baccharoides are high-calcium plants,Pyracantha fortuneana,Vitex negundo,Rhus chinensis,Smilax china,Miscanthus sinensis,Artemisia carvifolia,Imperata cylindrical,Clinopodium chinense,Digitaria sanguinalis are low-calcium plants. |
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