College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China; Environmental Impact Assessment Center, Nanjing Agricultural University, Nanjing, China.
College of Horticulture, Nanjing Agricultural University, Nanjing, China.
Sci Total Environ. 2018 Sep 1;635:333-342. doi: 10.1016/j.scitotenv.2018.04.127. Epub 2018 Apr 24.
Green roofs have increasingly been designed and applied to relieve environmental problems, such as water loss, air pollution as well as heat island effect. Substrate and vegetation are important components of green roofs providing ecosystem services and benefiting the urban development. Biochar made from sewage sludge could be potentially used as the substrate amendment for green roofs, however, the effects of biochar on substrate quality and plant performance in green roofs are still unclear. We evaluated the effects of adding sludge biochar (0, 5, 10, 15 and 20%, v/v) to natural soil planted with three types of plant species (ryegrass, Sedum lineare and cucumber) on soil properties, plant growth and microbial communities in both green roof and ground ecosystems. Our results showed that sludge biochar addition significantly increased substrate moisture, adjusted substrate temperature, altered microbial community structure and increased plant growth. The application rate of 10-15% sludge biochar on the green roof exerted the most significant effects on both microbial and plant biomass by 63.9-89.6% and 54.0-54.2% respectively. Path analysis showed that biochar addition had a strong effect on microbial biomass via changing the soil air-filled porosity, soil moisture and temperature, and promoted plant growth through the positive effects on microbial biomass. These results suggest that the applications of biochar at an appropriate rate can significantly alter plant growth and microbial community structure, and increase the ecological benefits of green roofs via exerting effects on the moisture, temperature and nutrients of roof substrates.
绿色屋顶的设计和应用越来越多，以缓解环境问题，如水土流失、空气污染和热岛效应。基质和植被是绿色屋顶提供生态系统服务和有益于城市发展的重要组成部分。由污水污泥制成的生物炭可以作为绿色屋顶的基质改良剂，但生物炭对绿色屋顶基质质量和植物性能的影响尚不清楚。我们评估了在自然土壤中添加不同比例（0、5、10、15 和 20%，v/v）的污泥生物炭对三种植物物种（黑麦草、景天和黄瓜）在绿色屋顶和地面生态系统中的土壤性质、植物生长和微生物群落的影响。我们的结果表明，添加污泥生物炭显著增加了基质的水分，调节了基质的温度，改变了微生物群落结构，促进了植物的生长。在绿色屋顶上应用 10-15%的污泥生物炭对微生物和植物生物量的影响最大，分别增加了 63.9-89.6%和 54.0-54.2%。路径分析表明，生物炭通过改变土壤充气孔隙度、土壤水分和温度对微生物生物量有很强的影响，并通过对微生物生物量的积极影响促进了植物的生长。这些结果表明，在适当的比例下应用生物炭可以显著改变植物的生长和微生物群落结构，并通过对屋顶基质的水分、温度和养分的影响，增加绿色屋顶的生态效益。
