Eucalyptus is a fast-growing, short-cycle, and high-efficiency tree species that is widely planted all over the world. Weeding is a special practice for Eucalyptus plantations that aims to cultivate seedlings and reduce vegetation competition for nutrients. In this study, a typical Eucalyptus plantation was selected as the research object, and the effects of two different weeding methods on soil evaporation and plant growth were studied. The results showed that mechanical weeding could effectively remove harmful weeds at an early stage, but after 30 days of weeding, all kinds of plants gradually recovered; herbicide weeding required long-term maintenance. The herbicide had the best control effect on Microstegium vagans (Nees ex Steud.) A. Camus, Dicranopteris dichotoma (Thunb.) Bernh, and Blechnum orientale, but the effect on shrubs was not obvious. The evaporation rate of soil increased rapidly within five days after mechanical weeding. After 139–200 days of weeding, the differences in evaporation between non-weeding, herbicide weeding, and mechanical weeding was decreased. The average daily evaporation was 0.52, 0.48, and 051 mm/d under these three practices. Meanwhile, weeding could promote Eucalyptus growth. Our results showed that weeding could significantly increase the height, diameter at breast height, and volume of Eucalyptus. One month after herbicide weeding or mechanical weeding (July), the height, DBH, and volume of Eucalyptus were significantly greater than those under non-weeding, but there was no significant difference between herbicide weeding and mechanical weeding. In addition, according to the different initial moisture contents, the evaporation rate increased with increasing initial moisture content and showed a very significant correlation.

Permanent gullies are a serious type of soil erosion. A special type of permanent gully, called “Benggang” severly affects agricultural production in hilly areas. To reveal the influence of Benggang erosion on granitic soil restoration and fertility, we selected three stages (active, semi-stable and stable) of Benggang recovery in the subtropical granite hilly region, and corresponding soil samples were collected to analyze the spatial variation in the soil physical and chemical qualities in the early stage of recovery. The soil physical properties and nutrients were significantly different in the runoff direction of each Benggang gully. There were significant differences in soil chemical properties and no obvious differences in physical properties among the different Benggang recovery stages. The results of principal component analysis showed that the level of soil fertility in the different Benggang recovery stages, ranked from high to low, was as follows: stable, semi-stable and active. Benggang vegetation restoration was an important factor for soil fertility restoration. Benggang ecological restoration can significantly improve the physicochemical properties and fertility of the soil. However, the soil fertility in gully erosion areas in this study still needs to be improved.

Background: Concentrations of heavy metals continue to increase in soil environments as a result of both anthropogenic activities and natural processes. Cadmium (Cd) and lead (Pb) is one of the most toxic heavy metals and pose health risks to both humans and the ecosystem. Therefore, effectively solving the problem of heavy metal pollution is the concern of soil workers. Among the existing remediation techniques, only the combined use of microorganisms and plants for remediation of heavy metal-contaminated soil is the greenest and most developed one. Consequently, based on this background, this study investigates the remediation mechanism of Pb and Cd heavy metals using the combined action of bacteria and Sedum alfredii Hance. Methods: In order to enrich the research theory of combined plant and microorganism remediation of heavy metal-contaminated soil, we constructed a heavy metal composite pollution remediation system by combining Pb and Cd-tolerant bacteria with the Pb and Cd hyperaccumulator plant—Sedum alfredii Hance to investigate its combined remediation effect on Pb and Cd composite contaminated soil. Results: The results showed that resistant bacteria were able to promote enrichment of Pb and Cd in Sedum alfredii Hance and J2 (200 ml of bacterial solution) was significantly (P < 0.05) more effective than J1 (100 ml of bacterial solution). The resistant bacteria were able to alleviate the toxic effects of Pb and Cd heavy metals on Sedum alfredii Hance and promote growth while reducing rhizosphere soil pH. The resistant bacteria were able to significantly reduce the effective state of Pb and Cd in the rhizosphere soil (P < 0.05), with the greatest reduction in the effective state of Pb in treatment A (Cd7Pb100 mg/kg), where J2 was reduced by 9.98% compared to J0, and the greatest reduction in the effective state of Cd in treatment C (Cd28Pb400 mg/kg), where J2 was 43.53% lower than J0. In addition, the resistant bacteria were able to increase the exchangeable state Cd content by 0.97 to 9.85%. The resistant bacteria had a weakly promoting effect and a highly inhibitory effect on the absorption of Pb by Sedum alfredii Hance. Conclusions: The resistant bacteria can change the rhizosphere environment and significantly improve the remediation effect of Sedum alfredii Hance on heavy metal cadmium. The role of “double-resistant” bacteria in promoting the accumulation of Cd was greater than that of Pb.