坝基堰塞湖沉积层改良及其促进植物生长的试验研究

Experimental Study on Improvement of Sediment Layer and Its Promotion of Plant Growth in Dam Foundation Dammed Lake

对沉积物进行改良并用于促进植物生长,达到生态修复的效果,实现沉积物的资源化利用,同时解决沉积物堆放占地问题,是目前水利水电行业绿色发展的重点与难点。通过水电工程现场扰动区的生态修复试验,研究了4种不同的改良剂对坝基堰塞湖沉积层的改良效果及对现场自然环境常见植物(格桑花、四季青、百日草、苜蓿、黑麦草和高羊茅)生长的影响。结果表明:添加牛羊粪肥、生物炭、粉煤灰和阴离子型聚丙烯酰胺(PAM)的沉积物理化性质显著优于现场自然表土(pH值除外),显著提高了自然条件下植物的生长生存能力。其中,施用牛羊粪肥和阴离子型PAM的沉积物处理组植物生长效果最佳,6种植物的株高均有显著提高(1.3~3.3倍)。植被的长势(株高和发芽率)与含水率、碱解氮、总氮、速效磷、有机质和阳离子交换量具有显著相关性(Mantel′s P≤0.05)。随着不同改良剂的添加,提高了0~10 cm深度处沉积物的含水率、碱解氮含量、总氮含量、速效磷含量、有机质含量和阳离子交换量,从而促进了植物的生长,平均提高幅度分别为24%、30%、29%、23%、45%和19%。该研究从坝基堰塞湖沉积物改良的角度为沉积物在生态修复中的实际应用提供了新的见解,对解决沉积物资源化利用及绿色水电发展问题提供了新的思路。

Improving the sediment and promoting the growth of plants,achieving the effect of ecological restoration,realizing the resource utilization of sediment,and solving the problem of sediment stacking and occupying land are the focus and difficulty of the green development of water conservancy and hydropower industry.Through the ecological restoration experiment of disturbed area in hydropower project site,the improvement effect of 4 different amendments on the sediment layer of dam foundation dammed lake and their effects on the growth of common plants in natural environment,such as Dasiphora fruticose L.Ilex chinensis Sims,Zinnia elegans Jacq.,Medicago sativa L.,Lolium perenne L.,Festuca elata Keng ex E.B.Alexeev,were studied.The results showed that the physicochemical properties of the sediments supplemented with bovine and sheep manure,biochar,fly ash and anionic polyacrylamide(PAM) were significantly better than those of natural topsoil(except pH),and the growth and survival ability of plants under natural conditions were significantly improved.Among them,the plant growth effect was the best in the group treated with cow and sheep manure and anionic PAM,which significantly increased the plant height of 6 species(1.3~3.3 times).Vegetation growth(plant height and germination rate) was significantly correlated with water content,alkali-hydrolytic nitrogen,total nitrogen,available phosphorus,organic matter and cation exchange capacity(Mantel's P≤0.05).With the addition of different amendments,the water content,alkali-hydrolyzed nitrogen content,total nitrogen content,available phosphorus content,organic matter content and cation exchange capacity of the sediment at 0~10 cm depth were increased by 24%,30%,29%,23%,45% and 19%,respectively,which promoted the growth of plants.This study provides a new insight into the practical application of sediment in ecological restoration from the perspective of sediment improvement,and a new way to solve the problem of sediment resource utilization and green hydropower development.