Questions and Answers
Which soil order is classified as comprising organic soils?
What is the size of soil particles that are classified as soil colloids?
What is the primary source of organic matter found in the soil?
What type of structure is characterized by the orderly arrangement of atoms in clay?
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What method involves the exchange of absorbed ions on soil colloids with ions in the soil solution?
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If a soil has a CEC of 100 me/100 gm and 20 me/100 gm of basic cations, what is the base saturation of the soil?
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Which microorganism is primarily responsible for converting nitrite to nitrate in the nitrogen cycle?
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The loss of nitrogen from the soil into the atmosphere as ammonia is known as what process?
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Which process describes the entry of surface applied water into the soil?
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Which ion is absorbed with the least force to soil particles?
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What is the hydraulic pressure of water held in the soil by capillary forces?
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What is the stable fraction of soil organic matter that remains after decomposition?
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Which group of soil microorganisms are capable of photosynthesis?
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What indicates the cation exchange capacity of a soil?
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Which method evaluates soil fertility by analyzing nutrient levels before planting?
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Which soil condition is referred to as white alkali soil?
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Which of the following options correctly describes an incomplete fertilizer material?
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Identify the most dominant basic cation found in agricultural soil.
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Which soil type has the highest water holding capacity at the same level of organic matter?
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Which combination of fertilizers would satisfy a recommendation of 90-60-60?
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Which chart is utilized in determining soil color?
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Which of the following serves as a source of sulfur in an inorganic fertilizer?
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Identify the micronutrient that is essential for nitrogen fixation in leguminous plants and is often deficient in acidic upland soil.
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What is the term for localized fertilizer placement along the crop's rows at the optimal time for growth?
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What is the process called that is not required for nitrification?
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Which microorganisms are primarily responsible for decomposing organic materials in soil?
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What is the process by which nutrients move from soil to a plant's roots, significantly influenced by root growth?
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What generally happens to the organic matter content of soil once it is cultivated?
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Which theory states that plant yield is limited by the nutrient available in the lowest relative amount?
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What is the most available form of nitrogen for crop production?
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Which property of soil significantly influences nutrient availability and microbial activity?
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What term is used to describe the yellowing of leaves due to nutrient deficiency?
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Which method is the most accurate for assessing soil fertility?
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What is one consequence of continuous flooding in waterlogged lowland rice soils?
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What is a key advantage of organic fertilizers compared to inorganic ones?
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When aluminum ions undergo hydrolysis, how many moles of H ions are produced?
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Which soil amendment is commonly used to alleviate soil acidity?
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What enzyme is primarily responsible for nitrogen fixation?
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Which of the following substances is not classified as a carbohydrate?
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What is a significant indicator of biological activity in the soil?
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Study Notes
Soil Science Key Concepts
- Soil Orders: Organic soils are classified as Histosols.
- Soil Particles: Particles smaller than 1 micron are referred to as soil colloids.
- Organic Matter Source: Most organic matter originates from plant residues.
- Clay Structure: Clay has a lattice structure for its crystalline arrangement.
- Ion Exchange: The process of exchanging ions on soil colloids is called cation exchange.
Soil Properties and Composition
- Base Saturation Calculation: Base saturation = (basic cations / CEC) × 100; example with CEC of 100 me/100 gm and basic cations of 20 me/100 gm results in 20%.
- Civil Engineer Role: Civil engineers can be classified as pedologists, studying soil properties.
- Soil Horizons: The parent material corresponds to horizon C in a soil profile.
- Mineral for Phosphorus: The primary phosphorus supplier in soils is apetite.
- Hardest Mineral: Diamond is recognized as the hardest mineral.
Nutrient Dynamics
- Major Nitrogen Form: The principal form of nitrogen present in soil is inorganic.
- Microorganisms in Nitrogen Conversion: Nitrobacter converts nitrite to nitrate in the nitrogen cycle.
- Nutrient Movement: Nutrients move from the soil to roots mainly through diffusion and mass flow.
- Soil Chemical Properties: Soil pH is vital for nutrient availability and microbial activity.
Organic Matter and Fertility
- Stable Soil Organic Matter: The remaining stable fraction after decomposition is known as humus.
- Organic Matter in Cultivation: Soil organic matter content typically decreases when cultivated.
- Nutrient Optimization: According to the law of minimum, plant yield is determined by the scarcest nutrient.
Fertilizers and Soil Amendments
- Incomplete Fertilizers: Fertilizers may lack one or more essential nutrients (e.g., nitrogen only).
- Organic vs. Inorganic Fertilizers: Organic fertilizers tend to provide long-term effects and improve soil health over time.
- Lime for Soil Acidity: Lime (calcium carbonate) is commonly used to alleviate soil acidity.
Environmental and Biological Factors
- Solar Radiation: Under complete cloud cover, infrared radiation is most intense at ground level.
- Soil Microflora: The most numerous and prominent soil microorganisms are bacteria.
- Nutrient Deficiency Symptoms: Chlorosis is the term for general yellowing of leaves due to nutrient deficiency.
Soil Management and Analysis
- Effective Soil Assessment: Soil analysis is the most accurate method for evaluating soil fertility.
- Nutrient Deficiency Indicators: Symptoms in crops serve as indicators for nutrient deficiencies, guiding fertilizer application.
- Alkali Soils: Classified with a pH of less than 8.5 and conductivity above 4 mmhos/cm, recognized as saline soils.
Nitrogen Management
- Nitrogen Fixation: The enzyme nitrogenase facilitates nitrogen fixation in plants.
- Immobilization of Nitrogen: Refers to the conversion of ammonium (NH4) to organic nitrogen, termed immobilization.
Special Cases in Soil
- Eco-Toxicity: Mine-tailing affected soil contains elevated levels of heavy metals, indicating soil problems.
- High Biomass Microflora: Fungi hold the highest biomass among soil microorganisms, critical for decomposition.
Nutrient Availability and Soil Interaction
- Cation Exchange Capacity (CEC): Measures the nutrient exchange potential of soil, related to negatively charged soil components.
- Organic Matter Application: Enhances nutrient availability, especially phosphorus, in acidic upland soils.
By focusing on these key aspects, one can grasp the fundamental principles of soil science and agriculture necessary for effective management and sustainable practices.
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Description
Prepare for your Agriculture Licensure Exam with this comprehensive Soil Science review quiz. Test your knowledge on soil orders, particle sizes, and organic matter sources. Perfect for students and professionals alike looking to deepen their understanding of soil science.
