The key pathways for synthesizing nanoparticles are physical and chemical, usually expensive and possibly hazardous to the environment. In the recent past, the evaluation of green chemistry or biological techniques for synthesizing metal nanoparticles from plant extracts has drawn the attention of many researchers. The literature on the green production of nanoparticles using various metals (i.e., gold, silver, zinc, titanium and palladium) and plant extracts is discussed in this study. The generalized mechanism of nanoparticle synthesis involves reduction, stabilization, nucleation, aggregation and capping, followed by characterization. During biosynthesis, major difficulties often faced in maintaining the structure, size and yield of particles can be solved by monitoring the development parameters such as temperature, pH and reaction period. To establish a widely accepted approach, researchers must first explore the actual process underlying the plant-assisted synthesis of a metal nanoparticle and its action on others. The green synthesis of NPs is gaining attention owing to its facilitation of the development of alternative, sustainable, safer, less toxic and environment-friendly approaches. Thus, green nanotechnology using plant extract opens up new possibilities for the synthesis of novel nanoparticles with the desirable characteristics required for developing biosensors, biomedicine, cosmetics and nano-biotechnology, and in electrochemical, catalytic, antibacterial, electronics, sensing and other applications.

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Invasive alien plants are one of the major threats to ecosystems. Many invasive plant species, such as Prosopis species, have been introduced around the world and can alter the soil properties of invaded ecosystems. It is one of the most aggressive invasive plant invaders in the North-West Province of South Africa, but little information is available about their influence on soil properties. This study was conducted to investigate the effect of Prosopis velutina invasion on selected soil properties at five different sites along the riverine system of the Molopo River in North West Province. At each study site, soil characteristics were measured from soil samples taken under P. velutina canopies, between canopies and in the benchmark stands free of Prosopis species. The effect on selected soil properties of P. velutina invasion varied between the three stands and between sites. In all the sites, almost all soils collected from under the canopies had a significantly higher soil exchangeable Ca, K, Mg, and Na, organic matter (OM), total nitrogen (TN), available phosphorus (P), Electrical conductivity (EC), and cation exchange capacity (CEC) than the other sample positions, except for the pH which had the high value in intercanopies. Significantly higher ( p < 0.05 ) values of almost all soil properties were found on the densely invaded sites (Tshidilamolomo I and Tshidilamolomo II) compared to lightly invaded sites (Mabule, Black Heat Farm, and Bray). However, it was difficult to generalise as the effects often appear to be site-specific. In addition, the findings also indicated that soils textural classes ranged between sand, silt, and clay in all study sites with a higher proportion of sand in the benchmark than in the soil under the canopies and intercanopies. Soil characteristics differed significantly more between sites than among positions. The site effects observed in this current study provide evidences that this species may occupy a relatively broad soil niche.

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Background: One of the main causes of land degradation in South Africa is bush thickening (BT) of mainly Senegalia or Vachellia species. Restoration methods are required to control BT, and to improve grass biomass production and soil conditions in South Africa.Objectives: The objectives of this study were to determine the effect of brush packing (BP) as a restoration method to increase grass biomass production, assess soil moisture after BP on different soil types, and document the perceptions of the local communities towards BP.Method: Methods included cutting the stems of woodies with a diameter of at least 10 cm at knee height by chainsaw and manual clipping after which an arborocide was applied to the stumps. A neutron probe was used to measure volumetric moisture content at two different soil depths. The grass biomass was analysed using ANOVA at a confidence level of 95%. Quantitative and qualitative approaches were used to gather information about the perceptions of local communities towards restoration in group discussions.Results: The short-term data showed that the implementation of BP as restoration method increased grass biomass production. The soil texture influenced the volumetric soil moisture. Higher soil moisture content was found in the deeper clayey soils. The local participants’ interpretation towards the restoration project was positive.Conclusion: The project increased the grazing potential and contributed to job creation to improve the well-being of the people in the community.