Municipal solid waste management has become one of the most important environmental management issues around the world. In this study, a bibliometric analysis of the literature related to municipal solid waste management from a global and South African perspective was performed using the software, VOSviewer. Relevant scientific literature was sourced from the Scopus database. Results showed that, globally, articles based on this topic started during the 1968–1969 period, whereas in South Africa such articles only appeared in 1996. The keyword analysis showed that most studies were related to waste-to-energy technologies, waste treatment, and other management aspects. Globally, emerging keywords representing new research areas were COVID 19-related waste streams, life-cycle assessments, and the role of municipal solid waste management in the circular economy. In contrast, South Africa’s prominent keywords were municipal solid waste, developing country, landfills, waste treatment, waste-to-energy technologies, pollution, greenhouse gas emissions, and others. Based on these results, and possible solutions to reduce the amounts of MSW generation rates, recommendations are made to bring South African research on par with international trends.

Herbicide mixtures are beneficial since they delay the occurrence of resistance to herbicides, provided that the herbicides used are effective at controlling the target weed species. Recently, plantago (Plantago lanceolata L.) was found to show 23 and 10-fold-resistance to glyphosate and paraquat. Experiments were carried out under controlled conditions to determine the efficacy of various herbicide concentrations and mixtures for the control of multiple resistant plantago at the two to three leaf stage. Proven plantago resistant (R) biotypes which had been shown to survive high glyphosate and paraquat dosages were used together with one susceptible (S) biotype in each experiment. The herbicides 2-methyl-4-chlorophenoxyacetic acid (MCPA), (400 g a.i. ha⁻¹), carfentrazone-ethyl (400 g a.i. ha⁻¹), and glufosinate (200 g a.i. ha⁻¹), and two combined mixtures consisting of paraquat + diquat (120 + 80 g a.i. ha⁻¹), and terbuthylazine + S-metolachlor (497.2 + 102.8 g a.i. ha⁻¹) were applied either alone or in mixtures resulting in 12 treatments. The herbicides and combinations were chosen for their distinct modes of action. The mixtures achieved 0% survival rates for the R and S biotypes except for glyphosate + MCPA and MCPA applied alone. The herbicide mixtures identified in the study together with other non-chemical control options may be used in the management of glyphosate- and paraquat-resistant plantago infestations.

Successful potato (Solanum tuberosum) cultivation depends on a variety of factors, of which fertilization forms an important component. Phosphorus (P) fertilizers differ not only in formulation (solid or liquid), but also in chemical form (orthophosphate or polyphosphate). To evaluate the response of potatoes to P sources, a study was performed to assess the productivity of potatoes under different ratios of orthophosphate and polyphosphate as P fertilizer. Potato cultivars (Mondial, Sifra, Lanorma, Innovator, Destiny, and Eos) were grown over two seasons using either 100% orthophosphate, 75% orthophosphate + 25% polyphosphate, 50% orthophosphate + 50% polyphosphate, or 100% polyphosphate. Plants demonstrated rapid vegetative development at the beginning when supplied with a balanced nutrient solution at an electrical conductivity (EC) of 1.5 mS cm⁻¹. Phosphorus applied as either 100% orthophosphate or 100% polyphosphate resulted in an increase in tuber number (24.5 and 20.8 tubers per plant, respectively) compared to 17.5 and 15.4 tubers per plant when 25% and 50% of the P was applied as polyphosphate. In both seasons the results indicated that applying P as orthophosphate had a superior effect on potato tuber fresh yield in comparison to applying P as polyphosphate.

Resistance to glyphosate in plantago (Plantago lanceolata L.), a serious weed in South Africa, was confirmed in 2003. More recently, a plantago biotype that is putatively resistant to both glyphosate and paraquat was reported. Seeds from a putatively susceptible (S) plantago population and from two putatively resistant populations (R1 and R2) were subjected to glyphosate and paraquat. To investigate possible multiple resistance, sequential application of glyphosate and paraquat was explored. The results showed an LD₅₀ of 891.89 g a.e. ha⁻¹ and 387.75 g a.i. ha⁻¹ for glyphosate and paraquat respectively for the S biotype. For glyphosate, the LD₅₀ value for R1 was 3842.61 g a.e. ha⁻¹. The LD₅₀ for the R2 biotype to glyphosate was 2020.39 g a.e. ha⁻¹. The paraquat LD₅₀ values for the R1 and R2 biotypes were 785.14 and 1246.43 g a.i. ha⁻¹ respectively, resulting in resistance indices of 2 and 3 respectively. Sequential application of glyphosate and paraquat was not effective in plantago management. The R biotypes showed resistance to both glyphosate and paraquat indicating possible multiple resistance.

Ribwort plantain (Plantago lanceolata L.) is a common weed in the winter rainfall region of South Africa. This weed is widespread across vineyards, orchards, and roadsides in the region. The weed has already evolved resistance to glyphosate and paraquat; however, the mechanism of paraquat resistance has not been documented. This study aimed to investigate the resistance mechanisms in this resistant (R) biotype. Dose–response trials conducted with R biotypes from the Robertson area reconfirmed paraquat resistance. Dose–response trials established that the paraquat rate causing 50% mortality (LD₅₀) for the R biotype is three times greater than for the susceptible (S) biotype. To find out how paraquat affected the photosynthetic performance of P. lanceolata, the quantum yield of photosystem II was measured. The photosystem reaction centres of the R biotype recovered 24 h after paraquat treatment. To evaluate paraquat transport in the plant cell, selective transport inhibitors were applied. Plantago lanceolata (S) biotypes had the highest electrolyte leakage after paraquat treatment. A combined radio/UV-HPLC was used for the separation and identification of paraquat and its metabolites. Paraquat degradation was not observed, indicating that metabolism was not a resistance mechanism within the R biotype. To assess leaf absorption and translocation, [¹⁴C]-labelled paraquat was applied to fully expanded leaves. There were no significant differences in paraquat absorption. However, paraquat translocation differed significantly across the R and S biotypes, indicating that non-target site resistance through reduced paraquat translocation was the main mechanism of resistance in the R biotype. As the resistance of weed species to post-emergence herbicides continues to increase, achieving sustainable weed management necessitates the implementation of diversified weed control strategies.