黄土高原地区水土流失造成严重的农业和生态环境问题,而植被能从根本上控制黄土高原的水土流失.以安塞县典型退耕坡地不同植物群落为研究对象,采用侵蚀针法,结合2012-2015年降雨数据及不同植物群落特征的分析,研究不同植被恢复坡地的土壤侵蚀特征.结果表明:研究期间,不同年份植被群落土壤侵蚀强度为丰水年＞平水年＞枯水年.不同植被类型群落防治土壤侵蚀的能力不同,具体为自然恢复灌木群落＞自然恢复草本群落＞人工灌木群落＞人工乔木群落.灰色关联度显示,降雨量与坡度是影响植被群落土壤侵蚀最重要的因素,乔灌木群落坡度＞降雨量,草本群落降雨量＞坡度.自然恢复植被群落枯落物盖度＞植被盖度,人工植被群落植被盖度＞枯落物盖度;因此,在当前植被条件下,未受到扰动的群落可有效减少降雨对土壤侵蚀的影响;在进行植被恢复时,应优先进行植被自然修复,适时适地引入乔灌木进行植被恢复人工调控,尽早促进乔木群落的林下植被发育,保护其林下灌草层和枯落物层,同时减少人为干扰.%[Background]The severe condition of soil and water loss in the Loess Plateau has resulted in critical agricultural and environmental problems.Vegetation restoration plays an essential role in controlling the soil erosion in the Loess Plateau.Yet there were few researches on analyzing the characteristics of soil erosion of different plant communities converted from slope cropland in the region.[Methods] The research was conducted between 2012 and 2015.Based on the succession of local plants,10 plant communities on abandoned slope croplands in 4 watersheds of Ansai County were selected and were classified in 4 groups:naturally restored herbage community (Artemisia scoparia,Stipa bungeana,Bothriochloa ischaemun,Artemisia gmelinii,and Artemisia giraldii),naturally restored shrub community (Sophora viciifolia),artificially established shrub community (Caragana intermedia and Hippophae rhamnoides) and artificially established arbor community (Robinia psendoacacia and Populus simonii).Totally 45 plots were selected and in each of these communities 3-6 plots were selected,in each plot 3 quadrats were placed as repetition.Annual soil erosion intensity was monitored by erosion pins placed in these plots.Characteristics of soil erosion of different plant communities were analyzed with ANOVA,combined with the hydrologic years divided by the characteristics of rainfall.Gray theory was used to determine the influence of potential indices caused soil erosion.[Results] Rainfall in research area was distributed unevenly,and rainfall erosivity was the driver factor causing the differences of soil erosion intensity of plant communities in different years.The ability of controlling soil erosion depended on the species of plant community:naturally restored shrub community (1 285.36 t/km2) ＞ naturally restored herbage community (2 152.65 t/km2) ＞ artificially established shrub community (2 320.50 t/km2) ＞ artificially established arbor community(2 661.14 t/km2).The soil erosion intensity of Robinia psendoacacia was the largest (3 875.02 t/km2) among these plant communities.Gray correlation analysis revealed that the rainfall and slope gradient had more impact on soil erosion than coverage in all communities.In shrub and arbor communities,the effect of slope gradient ＞ rainfall,but in herbage communities,rainfall ＞ slope gradient.When mentioned coverage,in natural restored community,cover of litters ＞ vegetation cover;and in artificially established community,vegetation cover ＞ cover of litters.[Conclusions] Under current status of vegetation,effects of precipitation on soil erosion reduced effectively in undisturbed plant communities.Natural vegetation should be restored initially with trees and shrubs introduced by human at proper time and place.Meanwhile,the undergrowth vegetation and litters in forest communities should be promoted earlier and protected,meanwhile human disturbances should be reduced as more as possible.
展开▼
