Calcium- and Magnesium-Enriched Organic Fertilizer and Plant Growth-Promoting Rhizobacteria Affect Soil Nutrient Availability, Plant Nutrient Uptake, and Secondary Metabolite Production in Aloe vera (Aloe barbadensis Miller) Grown under Field Conditions

Abstract

This work investigates the effects of an organic fertilizer enriched in Ca and Mg and two bacterial inoculants, applied alone and in combination, on soil fertility, plant growth, nutrition, and production of secondary metabolites, namely, acemannan and total phenolic compounds (TPCs), by Aloe vera (Aloe barbadensis Miller), under field cultivation. The first inoculum consisted of five native bacterial strains (Pseudomonas sp., Enterobacter sp., and three strains of Pantoea sp.), characterized in vitro as putative plant growth promoters, isolated from local organic farming fields of Aloe vera. The second inoculant was a commercial product (BACTILIS-S and HUMOFERT) and consisted of three Bacillus species: B. pumilus, B. amyloliquefaciens, and B. subtilis. The organic fertilizer (HUMO-CAL M-8O) was a mixture of humic and fulvic acids, with an additional CaCO3 (40% w/w) and MgO (4% w/w). The most significant increase in the content of acemannan and TPCs was detected under single application of the organic fertilizer, which was linked to enhanced concentration of Mg and Ca in the leaf gel. The concentration of acemannan tended to be increased with the combined application of the organic fertilizer and microbial inoculants. TPCs were significantly increased in both single and combined treatments, seemingly related to Fe concentration in the leaf rinds.

Analysis of nutrient loads, heavy metals and physicochemical properties of wastewater, wetland grass, and papaya samples: Gondar Malt factory, Ethiopia with global implication

“…The minimum and maximum concentrations of Mn were found in RW and WD, respectively. Mn was highly detected within WD; this might be due to its accumulation capacity in soil that could transfer the metal to barley and raw water [30] . The concentrations of Mn in all wastewater samples were found to be lower than the health-based standard guideline given by World Health Organization [41] .…”

“…The major sources of manganese are fertilizer, ores, rocks, and pesticides. Mn has not been particular toxicological issue, but its concentration in a particular spot may vary the taste and yet causes turbidity [30] , [7] . The distribution of Mn in wastewater samples was as follows: - WD > WAW > RW.…”

Effective microorganisms input efficiently improves the vegetation and microbial community of degraded alpine grassland

“…In addition, the beneficial microorganisms in EM have the ability of inhibiting harmful pathogens, and can also decompose cellulose and lignin and transform them into available nutrients for plants ( Liu et al, 2021 ; Khan, 2022 ). Furthermore, beneficial microorganisms can decompose some toxic substances such as sulfides and make plants to grow in a favorable environment ( Elnahal et al, 2022 ; Nikolaou et al, 2023 ).…”

Advancing horizons in vegetable cultivation: a journey from ageold practices to high-tech greenhouse cultivation—a review

“…However, the most resonant attribute of organic nutrients lies in their contribution to sustainable agricultural models. By championing biodiversity, these nutrients foster a vibrant soil microbiome that is integral for disease resistance and optimal nutrient uptake ( Nikolaou et al., 2023 ). Furthermore, the incorporation of organic waste products, such as compost and manure, epitomizes the principles of a circular economy, minimizes waste, and ensures that natural cycles are respected and replicated.…”