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Abstract Iron (Fe) deficiency in calcareous soils is a significant agricultural challenge, affecting crop productivity and nutritional quality. This study aimed to isolate, characterize, and evaluate Fe solubilizing rhizobacterial isolates from maize rhizosphere in calcareous soils as potential biofertilizers. Forty bacterial isolates coded as SG1, SG2, …, SG40 were isolated and screened for siderophore production, with ten showing significant Fe solubilizing capabilities. These isolates were further assessed for phosphate solubilization and exopolysaccharides production. The selected bacterial isolates were also screened under axenic conditions for their ability to improve maize growth. The isolates SG8, SG13, SG24, SG30 and SG33 significantly enhanced growth parameters of maize. Notably, SG30 showed highest increment in shoot length (58%), root length (54%), root fresh and dry biomass (67% and 76%), SPAD value (67%), relative water contents (69%), root surface area (61%), and Fe concentration in shoots (79%) as compared to control. The biochemical characterization of these strains showed that all these strains have capability to solubilize insoluble phosphorus, produce indole-3-acetic acid (IAA), and ammonia with catalase, urease and protease activity. Molecular identification through 16s rRNA gene sequencing confirmed high similarity (99.7–100%) of the selected isolates to various Bacillus species, including B. pyramidoids, B. firmicutes, and B. cereus. The study provides a strong base for developing eco-friendly, cost-effective biofertilizers to address Fe deficiency in crops and promote sustainable agriculture.

Plant growth-promoting rhizobacteria with multiple growth-promoting traits play a significant role in soil to improve soil health, crop growth and yield. Recent research studies have focused on the integration of organic amendments with plant growth-promoting rhizobacteria (PGPR) to enhance soil fertility and reduce the hazardous effects of chemical fertilizers. This study aims to evaluate the integrated application of biochar, compost, fruit and vegetable waste, and Bacillus subtilis (SMBL 1) to soil in sole application and in combined form. The study comprises eight treatments—four treatments without inoculation and four treatments with SMBL 1 inoculation in a completely randomized design (CRD), under factorial settings with four replications. The results indicate that the integrated treatments significantly improved okra growth and yield compared with sole applications. The integration of SMBL 1 with biochar showed significant improvements in plant height, root length, leaf chlorophyll a and b, leaf relative water content, fruit weight, diameter and length by 29, 29, 50, 53.3, 4.3, 44.7 and 40.4%, respectively, compared with control. Similarly, fruit N, P and K contents were improved by 33, 52.7 and 25.6% and Fe and Zn in shoot were 37.1 and 35.6%, respectively, compared with control. The results of this study reveal that the integration of SMBL 1 with organic amendments is an effective approach to the sustainable production of okra.

Background: The World Health Organisation (WHO) suggests haemoglobin that (Hgb) cut-off levels below 2SD from the population mean to initiate anaemia investigations. In the absence of epidemiological data, Hgb less than 11 g/dL is considered abnormal in children up to the age of 59 months (4 years and eleven months)., Objectives: This study reports on the Hgb cut-off levels among children at 1 and 4 years of age. The study compared the prevalence based on the WHO generic cut-off levels and population-specific cut-off-based value defined as below 2SD from the population mean., Design, Settings, and Participants: A cross-sectional record-based study of healthy children below the age of 59 months attending primary care settings in Qatar. 3 years of Hgb data were collected and analysed using descriptive analyses. We excluded children with any pre-existing disease or who have altered biological parameters indicating a non-healthy child., Results: 39407 Participants were stratified into different sub-groups according to age, gender, and ethnicity. Hgb levels were expressed as the mean ± 2SD for children of one and four years of age. Most children were from Western Asia (45.6%), followed by Northern Africa (23.7%), and Southern Asia (21.7%). Our findings for one-year-old children cut-off levels for anaemia might be as low as 9.9 g/dL and 10.6 g/dL for 4-years old., Conclusion: Hgb cut-off values may be set at higher levels for one-year and four-year age groups and many different ethnicities. Higher cut-off points may overestimate the problem as a public health issue. Children may be unnecessarily treated with iron or have needless investigations., Competing Interests: None., (AJBR Copyright © 2021.)