Practice Soils and details Questions and Answers

• The cation exchange capacity (CEC) of a soil is mainly governed by its content of which two components?
• The removal of fine materials such as clay and sesquioxides from the upper soil horizon by percolating water is known as:
• A soil sample showing an exchangeable sodium percentage above 15%, a pH exceeding 8.5, and poor structural stability caused by dispersed clay particles, wo...
• In high-rainfall tropical regions, intense leaching removes silica while iron and aluminium oxides accumulate in the soil profile, giving rise to reddish, ...
• A farmer wants to correct a highly acidic soil with a pH around 4.8, mainly to raise the pH closer to neutral and improve nutrient availability for the nex...
• Certain soil bacteria secrete iron-chelating compounds called siderophores mainly to scavenge and acquire which limiting nutrient?
• During composting, the intermediate high-temperature stage in which heat-tolerant microbes dominate and destroy pathogens is called the?
• The soil enzyme phosphatase primarily catalyses the release of inorganic phosphorus from which type of soil compounds?
• Ammonia-oxidising archaea, working alongside ammonia-oxidising bacteria in soil, contribute to which stage of the nitrogen cycle?
• Certain rhizobial bacteria release specific signal molecules called Nod factors mainly to trigger which process in legume roots?
• Under anaerobic, waterlogged soil conditions, sulphate-reducing bacteria convert sulphate into which foul-smelling toxic gas?
• A biocontrol microorganism that suppresses a fungal pathogen by directly parasitising and consuming the pathogen's own hyphae is exhibiting which mechanism...
• Certain Azotobacter species form thick-walled, resistant resting structures under unfavourable soil conditions, which are known as?
• Which soil water constant refers to the maximum amount of water a soil can retain against the pull of gravity after excess water has drained away, and is t...
• The rate at which water moves through a saturated soil under a unit hydraulic gradient, a key soil property used while designing sub-surface drainage syste...
• Which soil physical property is defined as the mass of oven-dry soil per unit volume of undisturbed soil, including its pore spaces, and is commonly used a...
• Which soil textural class generally offers the best combination of water-holding capacity, drainage and aeration, making it considered ideal for most agric...
• Continuous application of physiologically acidic fertilisers such as ammonium sulphate over several years, without any corrective liming, tends to:
• Green manuring, in which a fast-growing legume crop such as dhaincha or sunhemp is grown and ploughed into the soil while still green, is primarily practis...
• A soil test report shows very low organic carbon content along with poor soil aggregation and low water infiltration on a farmer's field. Which practice wo...
• 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?