砾石对青藏高原东缘水电工程取土场人工草地生物量分配的影响

Effect of gravel on artificial grassland biomass allocation in gravel-soil-taken field of hydroelectric project on the eastern Tibet Plateau

根据澜沧江上游如美水电站工程建设迹地生态环境保护的迫切需要,在该区域取土场开展人工草地植被恢复试验。研究将砾石置放于回填土壤(未筛分土和筛分土)的表层(0-10cm)、中层(20-30cm)和下层(40-50cm),播撒人工草种垂穗披碱草(Elymus nutans Griseb),进行人工草地建植,并监测群落冠层和根系生物量。结果表明,在回填未筛分土壤样地,砾石置放于表层、中层和下层的群落冠层生物量分别为136.5-526.7g·m^(-2)、98.9-372.5g·m^(-2)、79.8-373.2g·m^(-2),根系生物量分别为223.3-495.9g·m^(-2)、140.5-460.1g·m^(-2)、124.1-343.4g·m^(-2)。在回填筛分土壤样地中,砾石置放于表层、中层和下层的群落冠层生物量分别为134.8-415.5g·m^(-2)、88.3-288.9g·m^(-2)、73.9-260.5g·m^(-2),根系生物量分别为180.1-431.4g·m^(-2)、102.7-347.2g·m^(-2)、83.7-265.0g·m^(-2)。砾石置放于土壤表层可以显著提高人工草地的冠层和根系生物量(P<0.05)。研究结果揭示了砾石对青藏高原东缘水电工程取土场人工草地生物量分配的影响,以期对亚高山干旱区工程建设迹地与退化生态环境修复起到指导作用。

According to the urgent need for ecological environmental protection during the construction of Ru Mei hydropower station in the upper reaches of the Lan Cang River,we conducted a study on artificial vegetation restoration in gravel-soil-taken field.Gravels were placed in upper(GU,O-10cm),middle(GM,20-30cm)and deep(GD,40-50cm)layers of the backfll soil(unscreened and screened soils),grass species Elymus nutans Griseb was sown for establishing artificial grass,and community canopy and root biomass were monitored.The results showed that in the plots backflled with unscreened soil,the aboveground biomass of community ranged as 136.5-526.7g·m^(-2),98.9-372.5g·m^(-2),and 79.8-373.2g·m^(-2)for the treatment with gravels placed in the surface,middle,and deep soil layers,respectively,while the root biomass ranged as 223.3-495.9g·m^(-2),140.5-460.1g·m^(-2),and 124.1-343.4g·m^(-2),respectively.In the plots backilled with screened soil,the aboveground biomass ranged as 134.8-415.5g·m^(-2),88.3-288.9g·m^(-2),and 73.9-260.5g·m^(-2)for the treatments with gravels placed in the surface,middle,and deep soil layers,respectively,whilethe root biomass ranged as 180.1-431.4g·m^(-2),102.7-347.2 g·m^(-2),and 83.7-265.0g·m^(-2),respectively.Placing gravel in the soil surface layer can significantly increase the aboveground and root biomass of artificial grassland(P<0.05).Our result revealed the effect of gravel on artificial grassland biomass allocation in gravel-soil-taken field on the eastern Tibet Plateau,which plays an important guiding role in vegetation restoration in subalpine and semi-arid degraded ecosystems.