黄河源草地退化区2种鼠丘土壤风蚀规律

Soil wind erosion rule of two types of rodent mounds in a degraded grassland area of the Yellow River source zone

为阐明高寒草地啮齿类动物活动区鼠丘土壤风蚀特征和规律,以青海省河南县鼠害退化区高原鼠兔和高原鼢鼠鼠丘为研究对象,采用野外模拟风力侵蚀试验方法,对2类鼠丘土壤风蚀流失量和养分流失量的特征和规律进行研究,并对该2种鼠丘土壤风蚀差异进行对比和分析。结果表明:(1)在9 m·s^(-1)的恒风速吹蚀作用下,2种鼠丘土壤颗粒的快速流失主要集中在前15 min内,且高原鼠兔鼠丘土壤流失量显著高于高原鼢鼠鼠丘,约为高原鼢鼠鼠丘土壤流失量的1.5倍。(2)蠕移是鼠丘土壤流失最主要的运动方式,相同时间内2种鼠丘均呈现蠕移量>跃移量>悬移量,其中高原鼠兔鼠丘蠕移量、跃移量和悬移量分别为高原鼢鼠鼠丘的1.45倍、1.58倍、1.50倍。(3)鼠丘土壤养分含量明显低于原生草地土壤层,且养分含量呈现出原生草地土壤>高原鼠兔鼠丘土壤>高原鼢鼠鼠丘土壤。(4)鼠丘土壤养分流失和土壤流失具有相同的规律,养分流失主要取决于土壤颗粒的流失,高原鼠兔鼠丘的各养分含量指标的流失量较高原鼢鼠鼠丘增加1.42~3.53倍。研究结果将为阐述鼠害退化区土壤流失特征,揭示高寒草地退化机理和黄河源草地生态环境保护提供理论依据。

To clarify the characteristics and rules of soil wind erosion of rodent mounds in alpine grassland,studies were conducted on the Ochotona curzoniae and Eospalax baileyi mounds of He’nan County in Qinghai Province. The characteristics and rules of soil wind erosion and nutrient loss of the two types of rodent mounds were analyzed through a field-simulated wind erosion test, and the differences in soil wind erosion between the two types of rodent mounds were also compared and analyzed. The results of this analysis provide a theoretical basis for elucidating the characteristics of soil loss in rodent-infested degraded areas and reveal the degradation mechanism as well as the possible ways to protect the grassland ecological environment in the Yellow River Source Zone. The key results are as follows:(1) Under the action of 9 m·s^(-1)constant wind speed erosion, the loss of soil particles was concentrated in the first 15 min, and the soil loss of the Ochotona curzoniae mound was significantly higher than that of the Eospalax baileyi mound, which was approximately 1.5 times that of the Ochotona curzoniae mound.(2) With respect to the form of soil erosion, the amount of soil lost from the mounds was in the following order: surface creep > saltation > suspension, and the amount of soil lost in each of these forms in the Ochotona curzoniae mound was 1.45, 1.58, and 1.50 times the corresponding values in the Eospalax baileyi mound.(3) The nutrient content of the rodent mound soil was significantly lower than that of the original meadow soil;the order of nutrient content was original meadow soil > Ochotona curzoniae mound soil >Eospalax baileyi mound soil.(4) The soil nutrient loss law was similar to that of the rodent mounds, and the nutrient loss mainly depended on the degree of soil loss. The soil nutrient loss of the Ochotona curzoniae mound was 1.42-3.53 times higher than that of the Eospalax baileyi mound.