Background An increase in population has led to a higher demand for food. Meeting up this demand has necessitated the use of chemical fertilizers. However, utilization of these fertilizers has a considerable deleterious effect on the soil, plant, human, environmental sustainability, and only increase the cost and reduced profitability. With these identified problems, there is a need for efficient and sustainable methods regarding managing natural resources to enhance food production. Naturally, potassium (K) is an abundant element present in the soil but in an inaccessible form. There is therefore a need to seek an alternative method to improve the K availability to plants noting that K is an essential plant nutrient that plays a major role in plant physiological and metabolic processes. Subsequently, employing microbial potassium solubilizers is an efficient method to enhance the potassium availability in the soil, which in turn improves productivity. Therefore, this review discusses the various types of potassium solubilizing microorganisms in soil, their mechanism of action, and their importance in sustainable crop production. Main body Potassium solubilizing microorganisms (KSM) such as bacteria and fungi can solubilize K from an insoluble form to a soluble form to enhance uptake by plants. These microorganisms solubilize K through the production of organic acids such as tartaric acid, citric acid, and oxalic acid to release K from its minerals. Apart from making potassium available, these microbes can improve soil health and crop yield and act as bio-control agents by producing antibiotics. Potassium solubilizing microbes also produce hormones that help plants withstand both biotic and abiotic stresses. Hence, the application of KSM to agricultural soils will reduce the use of chemical fertilizers and enhance the sustainability of food production. Conclusion One of the most efficient ways of improving plant utilization of potassium in the soil is to use potassium solubilizing microbes, which can make potassium ions available from minerals of both igneous and sedimentary origins. The use of potassium solubilizing microbes as biofertilizers may be the awaited solution to increasing crop productivity, concerns linked to chemical fertilizer application, and earth resource diminution.

A study was designed to access the phytoremediation potential of microbial-assisted Chromolaena odorata of lead (Pb). The pots experiment was carried out in a Factoria experiment in a Completely Randomized Design, with nine treatments and three replications. Viable seeds of Chromoleana odorata were planted in 10kg of soil placed in each plastic pot having 10ppm, 20ppm, and 30ppm of Pb, respectively. Seedlings were inoculated with either Pseudomonas aeruginosa or Bacillus subtilis. The study was carried out for 12 weeks under natural conditions. Physiochemical properties of the soil were determined using standard methods. The results revealed that the microbes (Pseudomonas aeruginosa and Bacillus subtilis) used showed the potential for remediating lead. However, C. odorata inoculated with Bacillus subtilis remediated lead (Pb) was significantly higher than that inoculated with Pseudomonas aeruginosa at 10 weeks after planting. The levels of Pb in the roots and shoot of C. odorata after 12 weeks (B10, 0.22) showed that a more bioavailable pool of Pb was translocated from the root to leaves and stem in the Bacillus subtilis assisted C. odorata compared with other treatments. The results suggested that C. odorata has phytoextraction ability and could restore soil polluted with Pb. Bacillus subtilis assisted C. odorata to extract Pb via phytoaccumulation in shoot while Pseudomonas aeruginosa assisted C. odorata in removing Pb via phytostabilization. It also suggested that plant growth-promoting bacteria helped the uptake of lead from the soil.