Effects of Biochar and Sludge on Carbon Storage of Urban Green Roofs

Abstract

Green roofs can improve urban ecological conditions by mitigating the heat island effect and absorbing harmful gases. Soil additives can improve roof soil properties and promote the stability of the urban ecosystem. As soil additives, biochar and sludge are widely used in the ground, but their application on roofs is still scarce. This study examined the carbon storage potential of green roofs amended with sludge and biochar. The roof soil was composed of soil and varying proportions of the additives (0%, 5%, 10%, 15%, and 20%, v/v); Sedum lineare was then planted. The carbon contents of the soils and plants were measured for one year. The influence of biochar or sludge on the carbon content of the roof soil and the factors affecting the roof carbon storage potential were analyzed. The results showed that the carbon storage potential of a biochar green roof (9.3 kg C m −2) was significantly higher than that of a sludge green roof (7.9 kg C m −2). Biochar increased the carbon content of the green roof by improving the physical properties of the roof soil and promoting plant growth, whereas sludge increased the carbon content of the green roof by improving the chemical properties of the roof soil. Moreover, biochar could not only store large amounts of stable carbon, but also reduce the weight of the green roof, improve soil moisture, and provide a resourceful utilization of municipal sludge. Thus, biochar can be considered a material for promoting carbon storage on green roofs.

Effects of Sewage Sludge Application on Plant Growth and Soil Characteristics at a Pinus sylvestris var. mongolica Plantation in Horqin Sandy Land

“…As expected, this finding could be related to the higher rates of organic matter, TN, and TP in SS (Table 1). Similar results have been reported by Chen et al [69] and Carabassa et al [70], who observed that SS addition showed increases in the contents of SOC, TN, and TP, and thus positively improved the soil fertility. Sardans et al [71] pointed out that inputs of C, N, and P are the major processes that decide the stoichiometry of these nutrient elements in various ecosystems.…”

Heterogeneity of water-retention capacity of forest and its influencing factors based on meta-analysis in the Beijing-Tianjin-Hebei region

“…The fit index of path analysis explained 49%, 51%, and 61% of the variation in water-retention capacity for the canopy, litter and soil layer, respectively (Table 4). The Figure 6 Water-retention capacity of the soil layer for different environmental gradients significant factors affecting the water retention capacity were mainly explained by path map and effect value, and the influence effect was classified as direct effect, indirect effect, and total effect (Chen et al, 2018a;Chen et al, 2018b).…”

Changes in Water Retention and Carbon Sequestration in the Huangshan UNESCO Global Geopark (China) from 2000 to 2015

“…As a multivariate statistical method used to investigate the relationships among multiple factors in a natural system, the structural equation model (SEM) and its ecological application have received increasing attention in recent years [63][64][65][66][67][68][69][70][71][72][73]. An SEM was fitted by using the "lavaan" package in the R software [74][75][76].…”