Practice Soils and details Questions and Answers

• A type of soil erosion removes a fairly uniform, thin layer of topsoil across an entire field, leaving no visible channels or gullies, and often goes unnot...
• Which bacterial genus carries out the FIRST step of nitrification, oxidising ammonia to nitrite, as opposed to Nitrobacter, which performs the second step?
• Which genus completes nitrification by oxidising nitrite to nitrate, rather than oxidising ammonia to nitrite as Nitrosomonas and Nitrosococcus do?
• Azotobacter fixes nitrogen non-symbiotically under aerobic conditions. Which of the following fixes nitrogen non-symbiotically but specifically under anaer...
• Which type of mycorrhiza penetrates INSIDE root cortical cells to form arbuscules, as opposed to ectomycorrhiza, which forms a sheath OUTSIDE the root?
• Which soil microbial group is chemoautotrophic, deriving energy by oxidising inorganic compounds, unlike most cellulolytic and ammonifying bacteria, which ...
• Which soil process converts nitrate back into gaseous atmospheric nitrogen, ultimately causing a net loss of nitrogen from the soil-plant system?
• Which of the following soil organisms is a prokaryote lacking a true nucleus, unlike fungi, protozoa and algae, which are all eukaryotic?
• The nitrogen-fixing symbiosis formed between Frankia and non-leguminous woody plants such as Casuarina is specifically termed?
• Which group of bacteria oxidises methane (CH₄ ) to carbon dioxide under aerobic conditions, performing essentially the reverse function of methane-produc...
• White-rot fungi are notable among soil decomposers for their unusual ability to degrade which tough structural plant polymer?
• Ergosterol, used as a biochemical marker to estimate soil fungal biomass, is a key structural component of which fungal part?
• Ferric iron (Fe3+)-reducing bacteria in soil are typically active under which condition, similar to sulphate-reducing bacteria and methanogens?
• Bacteria such as Azospirillum colonise the root surface and rhizosphere closely but do not form nodules, fixing nitrogen through a process termed?
• The process by which ammonium ions become chemically trapped between the layers of certain clay minerals, reducing their immediate availability to plants, ...
• Certain soil fungi capture and consume nematodes using specialised structures such as adhesive nets or constricting rings, functioning mainly as a form of?
• The Shannon diversity index, when applied to soil microbial community data, is primarily used to measure?
• Which soil type, formed from the weathering of basalt or trap rock and typically found across the Deccan Plateau region, is known for its high clay content...
• The capacity of a soil's clay and organic matter to hold and exchange positively charged ions, such as calcium, magnesium, potassium and ammonium, is refer...
• Which of the following soil organisms is generally too small to be seen without a microscope?
• Adding organic manure to soil mainly helps to increase the number of?
• Dead leaves and plant parts falling on the soil are broken down by soil organisms into a dark, nutrient-rich substance called?
• Which of the following is an example of a soil-friendly practice that supports beneficial microbial life?
• Soil that has a good population of beneficial microorganisms is generally considered to be?
• Which of the following mainly provides food and energy for most soil microorganisms?
• A soil sample taken from a forest floor usually shows which level of microbial activity compared to sandy desert soil?
• Which of the following microorganisms is specifically used to prepare biofertilizers for legume crops such as gram and pea?
• The 'Winogradsky column', a classic laboratory setup in soil microbiology, is used to demonstrate?
• Which technique uses fluorescently labelled DNA probes to directly visualise and identify specific microorganisms within soil samples under a microscope?
• The 'rhizosphere effect' refers to the phenomenon where microbial population density near plant roots is significantly higher than in?
• Biological soil crusts, formed by cyanobacteria, mosses and lichens on arid soil surfaces, primarily contribute to soil?
• The enzyme nitrogenase, responsible for biological nitrogen fixation, requires which two essential metal cofactors to function?
• Laboratory assays measuring a soil's 'denitrification potential' commonly use which technique, which blocks the final reduction step so nitrous oxide accum...
• Soil microbial community 'resilience' specifically refers to its ability to?
• The 'priming effect' in soil refers to a short-term change in the decomposition rate of native soil organic matter following the addition of?
• A farmer applies gypsum to reclaim a sodic (alkali) soil with a high exchangeable sodium percentage. Gypsum works mainly by supplying which ion, which repl...
• Which of the following best describes a 'soil profile', a term commonly used in soil science and pedology to study soil formation and classification?
• Which quick field technique for estimating soil texture, without laboratory equipment, involves wetting a small soil sample and pressing it between the thu...
• Soils high in 2:1 type expanding clay minerals such as montmorillonite develop deep cracks during the dry season and become sticky and swollen during the w...
• Which soil condition most directly limits oxygen availability to aerobic microorganisms, thereby shaping overall microbial community composition?