Current Science

D. J. Bagyaraj ¹

Affiliations
1 NASI – Sr Scientist, Centre for Natural Biological Resources and Community Development, No. 41, RBI Colony, Anand Nagar, Bangalore 560 024, IN

Abstract

No Abstract.

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D. J. Bagyaraj ¹, M. P. Sharma ², D. Maiti ³

Affiliations
1 Center for Natural Biological Resources and Community Development, 41, RBI Colony, Anand Nagar, Bengaluru 560 024, IN
2 ICAR, Khandwa Road, Indore 452 017, IN
3 Central Rainfed Upland Rice Research Station (Central Rice Research Institute, ICAR), PB 48, Hazaribagh 825 301, IN

Abstract

Phosphorus (P) is one of the diffusion limited major nutrients, which is essential for plant growth. In soil, phosphorus occurs in three forms namely, soluble inorganic P, insoluble inorganic P and organic P. Uptake of P from soil solution is mediated by arbuscular mycorrhizal fungi (AMF) in addition to plant ischolar_mains. AMF are ubiquitous occurring in most of the soils. They are commonly found in association with agricultural crops. It is now proved beyond doubt that AMF greatly enhance plant growth. The improved growth is mainly attributed to uptake of diffusion limited nutrients such as P, Zn, Cu, etc. from soil. The other beneficial effects are their role in the biological control of ischolar_main pathogens, hormone production, greater ability to withstand water stress and synergistic interaction with beneficial microorganisms. It is believed that mycorrhizal plants absorb P only from the soluble P pools in the soil. Synergistic interactions between AMF and P-solubilizing microorganisms (PSM) are present which in turn helps plant growth. This is because PSM solubilize and release H₂PO₄ ions from unavailable forms of P and AMF help in the uptake of H₂PO₄ ions from soil. Field studies have shown that inoculation with efficient AMF not only increases growth and yield of crop plants but also reduces the application of phosphatic fertilizer by nearly 50%, especially in marginal soils deficient in nutrients. Though the rock phosphates available in India are of low grade and not fit for the manufacture of phosphatic fertilizer, they can be used with PSM plus AMF as a potential source of P for crop plants, thus bringing down the import of P fertilizers/rock phosphate in our country. Advantages of AMF have been attained through application of suitable AM fungal inoculum and augmenting native AM fungal activities in soil through manipulating agricultural practices in favour of these fungi.

Keywords

Agricultural Practices, AM Fungi, P Nutrition, Rock Phosphate.

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T. Abinaya ¹, D. J. Bagyaraj ¹, G. Thilagar ¹, R. Ashwin ¹

Affiliations
1 Centre for Natural Biological Resources and Community Development, 41 RBI Colony, Anand Nagar, Bengaluru 560 024, IN

Abstract

It is now well documented that arbuscular mycorrhizal fungi (AMF) improve fitness and growth of plants which are important in agriculture, horticulture and forestry. An important task in most AM studies is to determine accurately the number of infective propagules (IP) of AMF in soil, substrate, or inoculum. The most probable number (MPN) technique (or method of ultimate dilution) for enumerating viable microorganisms, is a possible solution to the problems faced when using the usual methods of counting AMF endophyte propagules.

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