青藏高原东部乡土植物对高寒沙化草地土壤性质的影响

以青藏高原东部高寒沙化草地为研究对象,通过比较分析狭叶红景天(Rhodiola rosea)、硬秆仲彬草(Kengyilia rigidula)、垂穗披碱草(Elymus nutans)和高山红柳(Salix cupularis)4种乡土植物对沙化草地的土壤理化性质、土壤酶活性及微生物生物量的影响,旨在为高寒草地沙化地生态植被的重建与恢复选择适宜的治理植物提供理论依据。结果显示:1)种植4种植物治理恢复5年后,土壤含水量均有显著升高(P0.05),土壤容重和土壤pH有不同程度的下降,垂穗披碱草处理下土壤含水量最高,与对照相较增加了357.70%;2)植被恢复显著提高了土壤中与碳氮磷循环相关的各种酶的活性(P0.05),其中狭叶红景天样地中的土壤纤维素酶、过氧化物酶、蔗糖酶、蛋白酶和磷酸酶活性最高,分别为对照的3.19、1.98、3.22、1.87和4.59倍。3)种植4种植物治理恢复5年后,不同土壤微生物生物量碳(MBC)、微生物生物量氮(MBN)均有显著提高(P0.05),狭叶红景天的MBC、MBN和微生物生物量碳氮比(MBC/MBN)均为最高,分别为对照的4.39、3.46和1.27倍;4)种植狭叶红景天和高山红柳样地,土壤酶活性与土壤理化性质及微生物生物量呈极显著(P0.01)和显著(P0.05)相关,种植垂穗披碱草样地,土壤酶活性与土壤理化性质及微生物生物量相关性较差。研究表明,4种植物种植5年后,狭叶红景天对高寒沙化草地的土壤特性改善更明显。

Effect of four native plant species on soil properties in desertified alpine meadow of the Tibetan Plateau

Desertification has already become a serious threat to alpine meadows in southeastern Tibetan Plat-eau,and to provide scientific evidence for selecting adaptive plant species and a reasonable direction for recove-ring desertified alpine meadows,the effects of four native plant species,including Rhodiola rosea,Kengyilia rigidula,Elymus nutans,and Salix cupularis,on soil physicochemical properties,soil enzymes,and soil mi-crobial biomass were explored in this study.The results showed that:1)After five years of vegetation restora-tion,soil moisture increased significantly (P<0.05),and increased the most (by 357.70%)in the treatment with E.nutans among the four plant species;meanwhile,both soil pH and bulk density decreased at different levels for the different species;2)Activities of soil enzymes related to carbon,nitrogen,and phosphorus cycles increased significantly (P<0.05),and the activities of cellulase,peroxidase,sucrase,protease,and phospha-tase in the treatment with R.rosea,which were 3.19,1.98,3.22,1.87,and 4.59 times that of the control,re-spectively,exhibited the highest values than the others;3)Soil microbial biomass carbon (MBC)and nitrogen (MBN)increased significantly (P<0.05),and soil MBC,MBN,and microbial biomass carbon to nitrogen ra-tio (MBC MBN),which were 4.39,3.46,and 1.27 times that of the control,respectively,were the highest in the treatment with R.rosea;4)The correlations between soil enzyme activity,soil physicochemical properties, and microbial biomass factors were significant in the two treatments with R.rosea and S.cupularis;however, these correlations were not observed in the treatment with E.nutans.The results indicated that R.rosea could embody the best approach to restore desertified alpine meadows among the four native plant species after five years of planting.