Perspectives of potassium solubilizing microbes in sustainable food production system - A review

Flashcards about Potassium Solubilizing Microbes in Sustainable Food Production

What role does potassium play in plants?

Potassium is a major essential plant nutrient that plays a pivotal role in plant physiological and metabolic processes, providing resistance against biotic and abiotic stresses.

What is the role of efficient rhizospheric microbes (ERMs) in potassium availability?

Efficient rhizospheric microbes (ERMs) are needed to effectively dissolve the non-exchangeable mineral potassium reserves in the soil and make it available to plants.

What are some examples of potassium solubilizing microbes (KSMs)?

Examples of KSMs include rhizobacteria (Bacillus edaphicus, B. mucilaginosus), fungal strains (Aspergillus terreus and Aspergillus sp.), and nitrogen-fixing rhizobacteria (NFR).

What are some mechanisms utilized by microbes for K dissolution?

Mechanisms include organic acid production, lowering soil pH, acidolysis, chelation, exchange reactions, and complexation.

What are some additional beneficial effects of ERMs, other than K solubilization?

Production of growth hormones, nitrogen (N) fixation, phosphorus (P) dissolution, enlargement of root system, and antibiotic production.

What is the main form in which potassium is absorbed by plants?

Potassium is absorbed by plants as a cation (K+).

What are some of the roles of potassium in plant physiology?

Photosynthesis, plant growth, metabolism, rate of assimilation, accumulation of sugars, root growth, seed development, fiber quality, water use efficiency, and biotic stress resistance.

What percentage of the earth's crust is composed of potassium?

Potassium comprises about 2.1% of the earth's crust.

In what forms is potassium found in the soil?

Insoluble mineral form (80-90%), interlayer K of non-expanded clay minerals (1-10%), and released in soil solution from a non-exchangeable pool.

What is the primary reason for K depletion in soils?

Introduction of high yielding cultivars and intensive cropping which consumes K in the amount exceeding ∼10 Mt in global crop lands each year.

Why is K management often ignored in fertilization practices?

K deficiency symptoms are not always as conspicuous as other macronutrients, and there is inaccurate perception about the availability of K through canal and irrigation water

What is a suggested alternative to synthetic K fertilizers?

Efficient soil microbes can play a key role in the natural K-cycle and quick solubilization of insoluble K bearing minerals

What are some mechanisms that soil microbes use to enhance K release from insoluble minerals?

Production of siderophore, phenolic compounds, organic acids, and other metabolites, which influence pH and redox reactions.

What percentage of total K in soils is generally available for plant uptake?

About 2% of the total K is available in solution for plant uptake.

What are the major K pools in most soils?

Primary K mineral or structural K such as silicate minerals viz., biotite, orthoclase, muscovite, feldspar, mica, vermiculite, illite and smectite.

What factors affect the availability of K in soils?

Weathering of K mineral fractions, level of K in other pools, nature and particle size of K bearing minerals, soil environments such as Eh and pH condition, and temperature.

What is the role of Plant Growth-Promoting Rhizobacteria (PGPRs)?

PGPRs help in soil processes such as weathering of soil, retention of nutrients, exudation of soluble compounds, decomposition of organic materials, mineralization of nutrients, phytohormone synthesis, nutrient cycling, and solubilization of K minerals.

What is the direct method of K solubilization by microbes?

Microbes help in K solubilization through strong organic acid production, acidolysis of the rhizosphere minerals, and carbonic acid based chemical weathering.

What is the indirect method of K solubilization by microbes?

Instead of acidolysis or lowering of pH, microbes also solubilize K minerals through chelation of the cations bound to K silicate, exchange reactions, solubilization by direct attachment of KSMs on mineral surfaces, metal complexing ligands, and release of phytohormones through microbes.

How do KSMs enhance plant growth?

KSMs promote plant growth through various direct and indirect growth promotion mechanisms such as N2-fixation, P-solubilization, production of hormones, organic acid production, siderophores, antibiotics, and antifungal compounds.