Rapid urbanization is one of the key factors that leads to defragmentation and the shrinking of agricultural land. It further leads to the generation of an ample amount of municipal waste. Several technologies have emerged in the past for its utilization, and in this regard, composting is one of the conventional approaches gaining popularity in modern agriculture. To overcome the possible criticality of intense urbanization, the concept of urban agriculture is taking shape. Municipal solid waste compost (MSWC) has been popularly explored for the soil amendments and nutritional requirements of crops. With this, the assessment of soil pollution (due to the heavy metals presently found in MSWC) is a required step for its safe application in agriculture. The present study aims at assessing the utilization of MSWC (in different ratios) to amend the soil and its impact on the growth and yield of brinjal (Solanum melongena), tomato (Solanum lycopersicum), and okra (Abelmoschus esculentus). The study also explored the uptake of heavy metals by plants and their risk to human consumption. The findings suggested that MSWC amendments upgraded the physio-chemical properties of soil, including organic matter (OM) and micronutrients, and increased the heavy metal concentrations in soil. Heavy metal analysis underlined the presence of several heavy metals both in soil and crops. Total metal concentration in soil increased with increased MSWC dosage. Concerning metal uptake by crop plants, 25% of MSWC was found to impart metal concentrations within permissible values in edible parts of crops. On the contrary, 50%, 75%, and 100% compost showed higher metal concentrations in the crops. A Health Risk Index (HRI) of less than 1 was found to be associated with soil amended with 25% MSWC. Our study implies that MSWC significantly improved the growth and yield of crops, and it can be considered an alternative to chemical fertilizer but only in a safer ratio (≤25%). However, further studies are required, especially on field conditions to validate the findings regarding metal accumulation.
Non-ribosomal peptides (NRPs) are a diverse group of bioactive compounds synthesized by microorganisms, and their antimicrobial properties make them ideal candidates for use as biocontrol agents against pathogens. Non-ribosomal peptides produced by Plant-Growth-Promoting Bacteria (PGPB) have gained interest for the biocontrol of plants’ bacterial and fungal pathogens. In this review, the structure and mode of action of NRPs, including their characterization and the characterization of NRP-producing microorganisms, are discussed. The use of NRPs in soilless agriculture and their potential as part of a sustainable plant disease control strategy are also highlighted. In addition, the review debates the commercial aspects of PGPB’s formulations and their potential as a biocontrol agent. Overall, this review emphasizes the importance of NRPs derived from PGPB in the biocontrol of plant pathogens and their potential to be used as an environmentally friendly and sustainable plant disease control strategy.
Rapid urbanization and population growth are stressing the present agricultural systems and could threaten food security in the near future. Sustainable development in agriculture is a way out to such enormously growing food demand. Plant growth-promoting bacteria (PGPB) are considered pivotal to providing adequate nutrition and health to plants and maintaining soil microbial dynamics. In the present study, municipal solid waste composts (MSWC) were studied for the presence of PGPB and their growth-promoting characteristics such as ammonium production, siderophores production, phosphorus solubilization and potassium solubilization, IAA (indole acetic acid), and HCN production. Four promising isolates were chosen and identified through 16S rRNA sequencing as Bacillus sp. strain L5-1, Bacillus pumilus strain EE107-P5, Bacillus sp. strain LSRBMoFPIKRGCFTRI6 and Bacillus sp. strain LPOC3. The potential of isolates is validated using Solanum lycopersicum (tomato) and was found to improve its growth significantly. The findings indicated the presence of potential Bacillus strains in MSWCs, and these composts can be utilized as biofertilizers for urban agricultural practices. However, studies concerning their impact on other crops’ growth and health are still underdeveloped. Since MSWCs might carry hazardous metals or chemicals, their evaluation for the safe application on the crops should also be assessed.