Soil substrate plays a central role in the vegetation restoration of high and steep slopes, especially in semi-arid regions. This study aims to develop an optimal soil substrate that can provide a favorable environment for the vegetation growth of the high and steep rocky slopes in semi-arid areas. Within the framework of planting hole greening technology, we developed a synthetic substrate comprising base soil, peat, water-retaining and agglomerating agents, biochar, and controlled-release compound fertilizer. We conducted pot experiments to assess the impact of compound additions on soil properties and Parthenocissus himalayana growth. Field tests on exposed, high, and steep rocky slopes in a semi-arid region validated the optimal ratio of substrate components. The results showed that the base soil-to-peat ratio significantly influenced soil density, moisture, pH, organic matter, nitrogen content, and vegetation growth (Ps < 0.05). The controlled-release compound fertilizer significantly affected soil electrical conductivity and alkali-hydrolyzable nitrogen content (Ps < 0.05). Meanwhile, the water-retaining agent, biochar, and agglomerating agent had inconsequential effects on soil characteristics and plant growth. The optimal substrate composition included a 7:3 ratio of base soil to peat, 1.5 g/L of water retainer, 10 mg/L of agglomerating agent, 5 g/L of biochar, and 5 g/L of controlled-release compound fertilizer. The field verification showed that the developed optimal substrate possessed desirable pore structure, moisture, and nutrients, resulting in excellent growth of Parthenocissus himalayana. This optimal soil substrate could be suitable for establishing vegetation on high, steep, rocky slopes in semi-arid areas using planting hole greening technology.

To understand the pollution characteristics of volatile organic compounds (VOCs) in the glass deep-processing industry, samples were collected using polyvinyl fluoride bags and quickly transferred to summa tanks for GC/MS/FID analysis. The emission characteristics of VOCs, the ozone formation potential and the secondary aerosol formation potential were studied. The results showed that the VOCs emitted by the six enterprises were mainly aromatics and OVOCs, accounting for 35% to 97% of the emissions, with high emission loads of alkanes and halocarbons from individual enterprises. The stack emissions from Enterprise 2 were as high as 38 mg/m³, while the emissions from the remaining five enterprises were all in the range of 1.7~4.1 mg/m³, probably because the terminal treatment facilities were not updated in a timely manner, resulting in excessive stack emissions from Enterprise 2. The characteristic pollutants, including OVOCs, aromatics and alkanes, which are mainly derived from spray painting and gluing, were screened in the six enterprises. Aromatics and OVOCs contributed the most to the ozone formation potential in the six enterprises, with some enterprises having a high contribution from alkanes and alkenes. On the basis of the secondary aerosol formation potential, toluene, benzene, ethylbenzene, o-xylene and m/p-xylene account for 98% of the six enterprises’ emissions. Glass enterprises should prioritise the control of benzene and OVOCs emissions. The glass processing industry mainly emits aromatics, OVOCs and alkanes. Through a preliminary study on the emission characteristics of VOCs in the glass deep-processing industry, we provided basic data for the reduction and control of VOCs in the glass deep-processing industry in China.

Soil porosity and moisture are critical indicators of soil quality. In coal–grain intercropping areas, centuries of coal industry activities have resulted in coal particle contamination, which has affected soil properties; however, its impact on soil porosity and moisture remains underexplored. This study compares coal-contaminated soils (CCS) and coal-free soils (CFS) in Jiaozuo, employing computed tomography (CT) scanning and moisture measurements to analyze how coal pollution influences soil porosity and moisture. Our findings indicate that CCS, compared to CFS, exhibit significant reductions in total porosity (TP), CT-measured porosity (CTP), number of pores (CTN), and the proportion and volume of water–air regulating pores (CTNWA/CTN and CTPWA). These results underscore that coal pollution substantially alters soil porosity and pore numbers. Additionally, coal pollution modifies soil pore morphology, leading to reductions in the number and length of pore throats (N_throat and L_throat) and causing the pores to become more flattened and rounded, with an increased inclination angle of interconnected pores (IA_ic). As coal pollution levels increase, interconnected porosity (P_ic) and coordination number (CN_ic) decrease, while isolated porosity (P_isolated) increases. In terms of moisture parameters, coal pollution diminishes the maximum water holding capacity, soil permanent wilting point, saturated hydraulic conductivity, and moisture evaporation rate. In contrast, field water-holding capacity and maximum effective water content are enhanced. Furthermore, with increased coal pollution, maximum water holding capacity, soil permanent wilting point, and saturated hydraulic conductivity decreased, whereas field water-holding capacity and maximum effective water content increased. Correlation analysis reveals that changes in CTN, N_throat, and L_throat significantly influence moisture parameter variations, with most pore parameter changes affecting saturated hydraulic conductivity. The observed effects of coal pollution on soil pore parameters are attributed to the filling and clogging actions of coal particles, while its impact on moisture parameters primarily results from these particles filling and clogging soil pores. This study provides a scientific basis for managing soil moisture in areas affected by coal pollution, particularly in coal–grain intercropping regions.