土壤沙化度对再生植物群落特征及草地生产能力的影响

Effects of soil desertification degrees on characteris⁃ tics of regenerated plant communities and grassland productivity

摘要:

【目的】分析土壤沙化度对草地再生植物群落特征及生产能力的影响，为川西北高寒沙化草地的植被修复与重建提供借鉴。【方法】选择植被破坏的 4 个沙化土地(ND 未沙化、LD 轻度、MD 中度和 HD 重度)，经 4 年种子自由迁入与自然竞争生长后，测定再生植被群落结构和优势种特点、功能群草种重要值和产量贡献率等指标。【结果】1)土壤沙化度对再生植物群落特征参数影响为基盖度＞投影盖度＞群落高度＞群落密度＞物种数，对优势种种类、种数与高度均有显著影响(P＜0. 05)。2)土壤沙化度对再生群落中功能群草种重要值及草地生产力有显著影响(P＜0. 05)，重要值受影响为豆科草类＞莎草类＞杂类草类＞禾草类，产量和贡献率受影响为莎草类＞杂类草类＞豆科草类＞禾草类。 LD、MD 和 HD 产量和贡献率最大的分别为禾草类、杂类草类和豆科草类。3)土壤未沙化和轻度沙化草地具有植被自我修复和再生能力，中重度沙化土壤的再生群落结构简单、生产力较低。【结论】川西北高寒草地沙化土地均可形成再生植被，土壤沙化度影响再生植被群落特征和草地生产性能，需依土壤沙化度采取相应的草地复壮技术。

Abstract:

【Objective】 This study aimed to understand the problem of restoration and reconstruction of damaged vegetation in Northwest Sichuan Alpine Grassland by analyzing the influence of soil desertification degree on the char‐ acteristics and productivity of grassland regeneration plant community. The research could provide reference for veg‐ etation restoration and reconstruction.【Method】 Four levels of soil desertification (ND non，LD light，MD moderate and HD heavy desertification) of vegetation destruction were selected as sample plots. The effects of soil desertifica‐ tion degrees on characteristics of regenerated plant communities and grassland productivity were studied after four years of free movement of seeds and natural competition of plants，by determined regenerated vegetation community structure ，the dominant species characteristics，as well as the grass species important value and yield contribution rate of the functional groups species.【Result】1) The influence of soil desertification degree on the characteristic pa‐ rameters of regenerated plant community was base coverage ＞ projection coverage ＞ community height ＞ commu‐ nity density ＞ species density. All those had a significant effect on the species，number and height of dominant spe‐ cies (P＜0. 05). 2) The degree of soil desertification had a significant effect on the important value of grass species and grassland productivity of functional groups in the regenerated community (P＜0. 05). The important value was affected by legumes ＞ sedges ＞ forbs ＞ grasses，and the yield and contribution rate were affected by sedges ＞ forbs ＞ legumes ＞ grasses. The largest yield and contribution rate were grasses，forbs and legumes at LD，MD and HD，respectively. 3) ND and LD soils had the ability of self repair and regeneration of vegetation，and the regenerated community in MD and HD soil had simple structure and low productivity.【Conclusion】 Sandy land could form corre‐ sponding regenerated vegetation，and soil desertification degree affected the characteristics of regenerated vegetation community and grassland production performance. Therefore，corresponding grassland rejuvenation techniques need to be adopted based on soil desertification degree.