Soil Types of India — Set 6

Correct Answer: B. Gully erosion

Gully erosion is a significant problem in the Chotanagpur Plateau region of Jharkhand and surrounding states. The hard crystalline rocks, combined with seasonal heavy rainfall and deforestation, lead to intense water erosion that forms gullies. The plateau's undulating terrain makes it particularly susceptible to gully formation. Reclaiming these gully-eroded lands is important for tribal communities who depend on agriculture in this region.

Correct Answer: C. Conducts soil research, classification, and conservation planning through institutes like NBSS&LUP

The Indian Council of Agricultural Research (ICAR) plays a central role in soil management through research, classification, and conservation planning. ICAR institutes like NBSS&LUP in Nagpur carry out systematic soil surveys and prepare soil resource maps. ICAR also conducts research on soil fertility, soil health management, and integrated nutrient management. Its research outputs guide national policies on soil conservation and sustainable land use.

Correct Answer: B. Holistic management of land, water, and vegetation within a watershed to prevent erosion and improve productivity

Integrated Watershed Management is a holistic approach to managing land, water, and vegetation within a watershed (drainage basin) to prevent soil erosion, improve water availability, and enhance agricultural productivity. It includes measures like check dams, contour bunding, vegetative barriers, and reforestation. The Government of India implements this through programmes like the Pradhan Mantri Krishi Sinchayee Yojana and Watershed Development Programme. It is one of the most effective long-term strategies for soil and water conservation.

Correct Answer: B. Optimal use of land resources to balance agricultural, forest, and industrial needs sustainably

The National Land Use Policy in India aims to ensure optimal and sustainable use of land resources by balancing agricultural, forest, industrial, and urban needs. It seeks to prevent the diversion of prime agricultural land to non-agricultural uses. The policy promotes soil and water conservation, wasteland development, and restoration of degraded lands. It provides a framework for state governments to plan land use in a scientific and sustainable manner.

Correct Answer: B. The upward movement of water through small soil pores due to surface tension

Soil capillarity refers to the upward movement of water through tiny soil pores due to surface tension forces. This phenomenon is important in agriculture because capillary action brings water from deeper, moist soil layers upward towards plant roots. Soils with fine particles (clay and silt) have greater capillarity than sandy soils. Understanding capillarity helps in irrigation management and predicting how moisture moves in the soil profile.

Correct Answer: C. B horizon

The B horizon is known as the zone of illuviation, where materials like clay, iron oxides, and organic matter that have been leached from the A horizon above are deposited. The term 'illuviation' means the deposition of materials in the lower horizon brought down from above. This makes the B horizon denser and more clay-rich than the A horizon. In Laterite soils, the B horizon is particularly enriched with iron and aluminium oxides.

Correct Answer: C. High organic matter and humus content

Dark-coloured soil generally indicates a high content of organic matter and humus, which gives the soil its dark brown to black colour. The more organic matter present, the darker the colour. Black soils and well-managed agricultural soils with high compost addition appear darker. High humus content improves soil structure, water retention, and nutrient supply to plants.

Correct Answer: B. Presence of iron oxide (Fe2O3)

Red soil gets its characteristic red colour from iron oxide (Fe2O3 or ferric oxide) present in the soil. When iron-containing minerals in the parent rock (igneous and metamorphic rocks) are oxidised under well-drained, aerobic conditions, they produce ferric oxide, which is red. The intensity of the red colour depends on the percentage of iron oxide present. In anaerobic (waterlogged) conditions, iron remains in its ferrous form and the soil appears grey or yellow.

Correct Answer: B. Erosion caused by the impact of falling raindrops on bare soil

Splash erosion is the first stage of water erosion and occurs when raindrops hit bare soil directly, dislodging soil particles. The energy of the falling raindrop breaks up soil aggregates and sends particles flying in all directions. The loosened particles are then more easily transported by flowing water. Maintaining vegetation cover or mulch on the soil surface is the most effective way to prevent splash erosion.

Correct Answer: A. Formation of small channels by concentrated water flow on sloping land

Rill erosion is an intermediate stage between sheet erosion and gully erosion, where small, numerous channels (rills) are formed on sloping land by concentrated water flow. As water from sheet flow concentrates into small streams, it gains erosive power and cuts small channels in the soil. Rills can be removed by ordinary tillage, but if neglected they develop into gullies. Rill erosion is common on sloping crop fields after heavy rain.