MCQ :: Soil Erosion Quiz For Competitive Exam

Correct Answer: Raindrops hit exposed soil and displace soil particles
Splash erosion is defined as the initial process where the impact of raindrops on bare soil dislodges soil particles, making them susceptible to being washed away.

Correct Answer: Increased water infiltration in soil
Excessive erosion degrades soil by removing topsoil, reducing organic matter, and damaging soil structure. This typically leads to decreased water infiltration due to surface sealing and compaction, not increased infiltration. Exposure of subsoil usually means less nutrient-rich soil is available.

Correct Answer: Kaolinite
Red soils often contain kaolinite clay and iron/aluminum oxides. Kaolinite has a high capacity to adsorb or 'fix' phosphorus, binding it and making it less available for plant uptake compared to minerals like montmorillonite.

Correct Answer: By surface water runoff
Sheet erosion occurs when a thin, relatively uniform layer of soil is removed from the land surface by shallow overland flow or surface water runoff, rather than concentrated flow in channels.

Correct Answer: Pressure
Water (rain, ice, flow), wind, and plant activities (root wedging, organic acids) are major agents of surface weathering and erosion. While pressure is involved in rock formation and subsurface processes (like pressure-release weathering), it's not a direct agent causing erosion on the Earth's surface like the others.

Correct Answer: Cannot be removed through normal tilling
Gully erosion represents an advanced stage of water erosion where concentrated runoff carves deep channels (gullies) into the land. These features are too large and deep to be obliterated by standard farming tillage operations, distinguishing them from smaller rills.

Correct Answer: Insoluble particles
Sedimentation is a physical process where heavier, insoluble particles suspended in a fluid (like water) settle out over time due to gravity. Soluble substances remain dissolved.

Correct Answer: Limited surface and groundwater availability
Rajasthan is largely an arid and semi-arid region characterized by low rainfall and high evaporation rates. This climate results in scarce surface water resources (rivers, lakes) and limited replenishment of groundwater, leading to chronic water scarcity.

Correct Answer: Tea
While red soils can support crops like cotton, pulses, and wheat with proper management, they are often not ideal for tea cultivation. Tea typically requires very acidic, well-drained soils rich in organic matter, often found in specific lateritic or forest soil regions, which differ from general red soil characteristics.

Correct Answer: All of the above
Vegetation provides multiple layers of protection against erosion: roots bind the soil particles, the plant canopy intercepts raindrops reducing their impact energy, and the stems/leaves slow down surface runoff and wind speed near the ground. Removing vegetation eliminates all these protective functions.

Correct Answer: Formation of soil
Weathering breaks down rocks into smaller particles (regolith), and erosion transports these particles. Over long periods, the accumulation of this weathered material, mixed with organic matter, leads to the formation of soil.

Correct Answer: Cover cropping
Cover cropping involves planting specific crops primarily to protect the soil surface from erosion during periods when the main cash crop is not present. This practice reduces raindrop impact, slows runoff, and improves soil health, thereby minimizing water erosion.

Correct Answer: Cotton and pulses
With appropriate management practices like irrigation and fertilization, red soils can be made suitable for growing moderately drought-tolerant crops like cotton and various pulses (e.g., groundnut, pigeon pea, millets). Other crops listed often have more specific requirements (waterlogging for rice, high water/fertility for sugarcane, specific soil/climate for tea/coffee/jute).