Science · X-Factor Notes
Biofertilizer revision notes for UPPCS Prelims.
High-Yield Revision| Concept | What to remember | Asked in UPPCS |
|---|---|---|
| Definition | Biofertilizers are preparations containing living cells or latent cells of efficient strains of microorganisms. They are also referred to as living microorganisms of bacterial, fungal, and algal origin. | |
| Function | They increase the nutrients of host plants when applied to their seeds, plant surface, or soil by colonizing the rhizosphere or the interior of the plant. | |
| Mechanism | They add nutrients through the natural processes of nitrogen fixation and solubilizing phosphorus. They augment the availability of nutrients in a form easily assimilated by plants. | |
| Benefits | They are cost-effective, restore the soil's natural nutrient cycle, and help build soil organic matter. Their use is recommended to switch to organic farming as chemical fertilizers cause pollution and deplete soil minerals. | U.P. Lower Sub. (Pre) 1998 (Related to necessity of chemical fertilizers for phosphorus) |
| Concept | What to remember | Asked in UPPCS |
|---|---|---|
| Examples of Biofertilizers | Examples include Rhizobium, Blue-green algae (Cyanobacteria), and Azolla. Also listed are Azotobacter, Anabaena, Nostoc, and Frankia. | UPPCS (Pre) 2002, UPPCS (Pre) 2001, UPPCS (Mains) 2009, UPPCS (Spl) (Mains) 2008 |
| Rhizobium | A nitrogen-fixing organism. These bacteria combine with the cells of the roots of legumes (pulses) in specialized structures called root nodules. | UPPCS (Pre) 2019, UPPCS (Pre) 2019 |
| Rhizobium japonicum |
| Concept | What to remember | Asked in UPPCS |
|---|---|---|
| Azolla (Aquatic Fern) | A floating aquatic fern commonly used as a biofertilizer in water-logged rice fields (paddy). Its ability stems from a symbiotic association with the aquatic fern Azolla and Anabaena (a Blue-green algae). | U.P. U.D.A./L.D.A. (Spl.) (Mains) 2010, U.P.R.O./A.R.O. (Mains) 2014, U.P. P.C.S. (Pre) 2023, UPPCS (Mains) 2011 |
| Blue-green algae (Cyanobacteria) | Used to supply nitrogen to paddy (rice). This organism, along with Azolla and Nostoc, promotes nitrogen fixation in rice crops. |
| UPPCS (Pre) 2006 |
| Azotobacter | A nitrogen-fixing organism (bacteria) that naturally fixes atmospheric nitrogen in the rhizosphere (the zone surrounding the root of plants). | U.P. Lower Sub. (Spl.) (Pre) 2003, U.P. Lower Sub. (Spl.) (Pre) 2002 |
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| Non-Nitrogen-Fixing Example | Mycorrhiza is a symbiotic association between a fungus and a plant and is not a nitrogen-fixing organism. | U.P. P.C.S. (Mains) 2017 |
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| Microorganisms Used | Biofertilizers include microorganisms such as Cyanobacteria (Blue-green algae), Fungi (Mycorrhiza, Aspergillus), and various Bacteria (Rhizobium, Azotobacter, Pseudomonas). | U.P. R.O./A.R.O. (Mains) 2016, U.P. P.C.S. (Mains) 2012 |
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| UPPCS (Mains) 2010 |
| Leg-haemoglobin | Found in legume root nodules, it is essential for supplying sufficient oxygen to the nodule bacteria for the nitrogen fixation process to occur. | UPPCS (Mains) 2005 |
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| Biological Nitrogen Fixation | Associated microbes include Rhizobium, Azotobacter, and Cyanobacteria. | U.P. P.C.S. (Mains) 2004 |
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