Salt stress is widely recognized as one of the important abiotic stressors results the severe reduction of medicinal plants growth and its herb yield. It also critically reduces the production of medicinally important active chemical content in the plants. There are three main stages on the growth of medicinal plants where the high salinity stress severely affects the plant growth. Recent studies showed that there is reduction of herb yield around 60% and simultaneous active chemical content reduction of around 50% under the exposure of high salinity of 300 mM of NaCl concentration. There are many reasons behind the reduction of growth of medicinal plants due to salt stress. There are also morphological, physiological and biochemical changes observed on the medicinal plants but there is still mystery exists whether any ultra-structural changes occur on the medicinal plants for salinity stress. The strategies employed in recent years to reduce the effect of high salinity stress on medicinal plant production mainly focused on a selection of salinity tolerant host genotypes. However, such efforts need high cost and inputs, there is an immediate urgency to build simple, low cost, sustainable and short term methods for salinity stress management. Hence the use of plant growth promoting microbes inhabiting rhizosphere, phyllosphere or endosphere might play a significant role in this aspect, if we exploit them as a multi-trait PGPR like stress-tolerant, PGPR activities, manipulation of signalling between both partners as plant and microbes with specific compatible solutes.

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The present investigation was focused on isolation and in vitro characterization of high abiotic stress tolerance, PGPR traits and dinitrogen fixation efficiency among cultivable rhizobia nodulating mothbean, clusterbean and mungbean. A total of 201 rhizobial isolates were retrieved from 101 different nodule samples collected from various locations of four districts i.e. Churu, Bikaner, Jaisalmer and Barmer situated under hyper-arid zone of Rajasthan, India. Around 70% of rhizobial isolates showed steady growth at 30% of polyethylene glycol 6000 (PEG 6000) and 30% of isolates showed tolerance at 40% PEG when drought tolerance of different rhizobia were assessed. Similarly 70% of the rhizobial isolates showed luxurious growth at temperature of 40 °C and only 30% of isolates showed survival ability at 45 °C. Combined abiotic stress tolerance experiment revealed that 54 rhizobial isolates were tolerant to 30% PEG and 40 °C while only 16 isolates showed high drought tolerance of 40% PEG 6000 and high temperature tolerance at 45 °C. In vitro assessment of dinitrogen fixation efficiency showed all 54 stress tolerant isolates possessed dinitrogen fixation ability with different degrees of efficacy. Stress tolerant rhizobial isolates also harbored multiple PGPR traits like phosphate solubilization, IAA production, ammonia excretion, bacteriocin production and ACC deaminase activity. Hence, our result showed a promising percentage (30%) of different rhizobial isolates can be used further in situ trials in pot house and field conditions as high abiotic stress tolerant isolate accompanying with multiple PGPR traits for future bioinoculant production.

Compressed stabilized earth blocks (CSEBs) offer a cheaper and environmentally sustainable alternative to traditional building materials for construction. In addition to addressing waste disposal difficulties, the inclusion of waste additives may improve the characteristics of compressed earth blocks (CEBs). This article attempts to outline the findings of researchers who have utilized the various manufacturing processes and investigated the influence of binders and fibers on the properties of CEBs. A systematic search of Web of Science and Scopus electronic databases for works on soil blocks published between 2012 and 2022 yielded 445 articles, while reports, case studies, conference papers, and non-English articles were omitted. Keywords such as “Soil blocks”, “Earth bricks”, and others were used to identify eligible studies. This study has been segmented into five sections, including a descriptive examination of articles and authors who have investigated soil blocks, a comparative analysis based on their manufacturing processes, and physical, mechanical, and durability aspects of the CSEBs, which were analyzed to determine the impact of additives. The PRISMA 2020 standards were followed in the evaluation of each record, which resulted in the identification of 61 articles that were pertinent to the study’s objective. The comparative analysis of the articles reveals that the binders were more significant in improving the compressive strength, cyclic wetting-drying and erosion (durability) aspects of the soil blocks, while fibers were effective in enhancing their flexural and thermal performance. The literature review indicates that if the minimum permissible limits are met, waste materials have the potential to partially replace the soil. In addition, this study suggests establishing standardized manufacturing norms and testing protocols to ascertain the quality and safety of CSEBs used in construction. However, this study is constrained by the limited databases used, governed by keywords, electronic resources and timeframe that could be used as research avenues in the future.