不同植被恢复措施下高寒沙化草地植被与土壤变化特征

Characteristics of Vegetation and Soil Under Different Restoration Measures in Alpine Desertification Grassland

草地沙化是青藏高原草地生态环境恶化的显著问题之一,为研究不同恢复措施对高寒沙化草地植被与土壤的影响,以沙化草地(DG)、人工草本恢复草地(AG)、人工灌丛恢复草地(AS)以及天然草地(NG)为研究对象,基于植被群落和土壤特征的变化及两者的相互关系,评价了不同人工植被恢复措施对高寒沙化草地22年的恢复效果。结果表明:(1)AG和AS分别使DG的地上生物量增加至109.21,1293.21 g/m^(2),但2种恢复措施的草本地上生物量均显著低于NG,而AG的植被群落物种丰富度比AS显著低31.48%(p<0.05)。(2)与DG的0—10 cm表层土壤相比,AG的土壤孔隙度、含水量、总碳和总氮含量分别显著提高7.94%,67.95%,22.09%和257.14%,AS的这些指标也分别显著提高6.41%,43.00%,17.18%和242.86%;但2种恢复措施的土壤碳氮养分含量均显著低于NG(p<0.05)。(3)AS和AG的土壤有机碳矿化总累积量分别比DG显著提高133.39%和116.96%,但均显著低于NG,2种恢复措施间无显著差异(p>0.05)。可见,人工植被恢复措施显著促进沙化草地植被以及土壤恢复,但灌丛恢复更有利于提高植被物种丰富度,而草本恢复更有利于增加沙化草地土壤水分。

Grassland desertification is one of the most serious ecological and environmental problems in Qinghai-Tibet Plateau.To investigate the characteristics of vegetation and soil under different restoration measures in alpine desertification grassland,desertification grassland(DG),artificial herbage grassland(AG),artificial shrub grassland(AS)and natural grassland(NG)were selected to study the changes of vegetation community and soil characteristics and their relationship,and to evaluate the restoration effect of different artificial vegetation restoration measures on alpine desertification grassland after 22-year restoration.The results showed that:(1)AG and AS increased the aboveground biomass of desertification grassland to 109.21 and 1293.21 g/m2,respectively.However,the aboveground biomass of herbs under AG and AS were significantly lower than that of NG,and the species richness of AG was significantly lower than that of AS by 31.48%(p<0.05).(2)Compared with the 0—10 cm surface soil of DG,the soil porosity,water content,total carbon and total nitrogen contents of AG significantly increased by 7.94%,67.95%,22.09%and 257.14%,respectively.And these indexes of AS significantly increased by 6.41%,43.00%,17.18%and 242.86%,respectively.However,the content of soil carbon and nitrogen in the two restoration measures were significantly lower than that of NG(p<0.05).(3)The total accumulation of soil organic carbon mineralization in AS and AG was significantly higher than that in DG by 133.39%and 116.96%,respectively,but both were significantly lower than that in NG,and there was no significant difference between the two restoration measures(p>0.05).Therefore,artificial vegetation restoration measures significantly promoted vegetation and soil restoration in desertification grassland,but shrub restoration was more conducive to improve the species richness of vegetation communities,while herb restoration was more conducive to increase soil moisture of desertification grasslands.