Search

Soil inorganic carbon (SIC) is an essential component of the soil carbon pool and plays a vital role in the global carbon cycle and climate change. However, few studies have examined the effects of different agronomic practices on the SIC content. This paper aims to study the effects of different agronomic practices on the SIC content in the 0- to 40-cm soil layer of dryland fields; the innovations are intended to explore the relative importance and synergistic effects of different agronomic practices on the SIC content of the plough layer of dryland fields. We screened out 136 peer-reviewed articles worldwide from 1990–2022, with a total of 2612 valid data pairs, using meta-analysis to assess the effects of different agronomic practices on the SIC content of the plough layer of dryland fields. Compared to conventional tillage (CT), both no-tillage (NT) and plastic film mulching (PM) were able to increase the SIC content in the 0- to 40-cm soil layer of dryland fields. NT increased the SIC content by 15.07 ± 3.48%, while PM gradually increased SIC accumulation as the soil layer deepened, with the greatest increase in SIC content in the 30- to 40-cm soil layer at 11.61 ± 5.89%. When organic manure application (M) and straw return mulching (SM) were applied, the SIC content in the 0- to 40-cm soil layer of dryland fields showed a non-significant reduction trend, with the largest changes in SIC content in the 0- to 10-cm soil layer, at 5.23 ± 2% and 4.69 ± 3.53% reductions, respectively. No-tillage straw return (NTS) significantly increased the SIC content in the 0- to 40-cm soil layer of dryland fields by 77.34 ± 5.6%, which was significantly higher than the independent effects of NT and SM, showing a more substantial synergistic effect. Different agronomic practices have different effects on the SIC content of dryland fields in the 0- to 40-cm soil layer, with NTS > NT > PM > SM > M. Among practices, NTS, NT and PM can increase the SIC content of the plough layer of dryland fields; in particular, NTS can increase the SIC content of 0- to 40-cm in dryland fields to the greatest extent through a synergistic effect. At the same time, SM and M showed an insignificant reduction effect.

The use of phytoremediation technology to remove heavy metal ions from aquatic environments or reduce their toxicity offers the possibility of restoring the ecological environment of polluted water bodies. Based on available literature on heavy metal absorption by aquatic plants, we conducted a meta-analysis to study the absorptive capacities of different plants as well as the factors that influence their Hg-absorption performance. Seventeen plant families, including Araceae, Haloragaceae, Hydrocharitaceae, and Poaceae, have a strong Hg-absorption capacity. The root systems of aquatic plants belonging to these families are primarily responsible for this remediation function, and only a limited proportion of Hg+ that enters a plant via the root system is transferred to other plant organs. Additionally, the diversity of plant life habits (e.g., floating, submerged, and emergent) and the water pH significantly influence the ability of plants to absorb Hg. It is expected that this study will provide a reference for the cultivation of aquatic plants for restoring the ecological environment of Hg-polluted water bodies.