Soil Types of India — Set 14

Correct Answer: C. Soil Health Card Scheme

The Soil Health Card Scheme provides cards to farmers showing the nutrient status and health of their soil. Launched in 2015, it aims to test every farm in India once in three years and provide customized fertilizer recommendations. The scheme is implemented by the Ministry of Agriculture and Farmers Welfare. It helps farmers make informed decisions about fertilizer use, reducing costs and improving yields while protecting soil health.

Correct Answer: C. Laterite soil

Laterite soil is most suitable for coffee cultivation in India. Coffee plants prefer well-drained, acidic soils, which is characteristic of Laterite soil in the hilly regions of Karnataka, Kerala, and Tamil Nadu. The Baba Budan Hills in Karnataka, which grow the famous Mysore coffee, are on Laterite soil. The combination of Laterite soil, high altitude, and moderate rainfall makes India's Western Ghats one of the finest coffee-growing regions in the world.

Correct Answer: C. Montmorillonite

Montmorillonite (also called smectite) clay mineral is predominant in Black soil and is responsible for its characteristic shrink-swell behaviour. Montmorillonite has a 2:1 clay structure that allows water molecules to enter between the silicate sheets, causing the clay to expand (swell) when wet. When dried, these water molecules leave and the clay shrinks and cracks. The high surface area and charge of montmorillonite also makes Black soil highly sticky when wet.

Correct Answer: C. Most nutrients are available in the pH range of 6-7, while extreme pH reduces availability

Soil pH profoundly affects the availability of nutrients to plants. In the pH range of 6-7, most macro and micro nutrients are available in forms that plants can absorb. At very low pH (below 5), aluminium and manganese become soluble and toxic, while phosphorus becomes locked up with iron and aluminium. At high pH (above 7.5-8), micronutrients like zinc, iron, manganese, and copper become insoluble and unavailable. Managing soil pH is therefore crucial for optimal crop nutrition.

Correct Answer: C. Water erosion and deposition by rivers

Alluvial soil is formed primarily by the water erosion of rocks and soil in upper catchments, with the eroded material being transported by rivers and deposited in plains, valleys, and deltas. The process of river erosion, transportation, and deposition creates the deep, fertile alluvial deposits of the Indo-Gangetic plains. The coarser material is deposited first near the source (forming Bangar), while finer material is carried further to active flood plains (forming Khadar). This ongoing process continuously adds new alluvium to the plains.

Correct Answer: B. It helps farmers understand the fertility status of their soil and apply the right fertilizers in correct amounts

Soil testing is important for farmers because it reveals the nutrient status of their soil — which nutrients are adequate, deficient, or in excess. Based on soil test results, farmers can apply the correct type and amount of fertilizer to meet crop requirements exactly. This prevents over-fertilization (which wastes money and causes environmental pollution) and under-fertilization (which reduces yields). Soil testing is the foundation of scientific and economical crop nutrition management.

Correct Answer: B. Gujarat on Red and Sandy soil

Gujarat is one of the largest producers of groundnut in India, grown primarily on the light, well-drained Red and Sandy soils of Saurashtra and North Gujarat. Groundnut requires well-drained, loose soil that allows its pegs (developing pods) to penetrate easily. Heavy clay or waterlogged soils are unsuitable. Andhra Pradesh is also a major groundnut producer on Red soil. Tamil Nadu and Karnataka also grow significant amounts on Red soil.

Correct Answer: B. Pedogenesis

Pedogenesis is the scientific term for the process of soil formation from parent rock. It involves the physical weathering (breaking down of rock into smaller particles by temperature changes, freeze-thaw, etc.), chemical weathering (dissolution of minerals by water and acids), and biological processes (activity of organisms adding organic matter). Over hundreds to thousands of years, these processes transform bare rock into a productive soil with distinct horizons. The nature of the parent rock significantly influences the type of soil formed.

Correct Answer: B. Parent material, Climate, Organisms, Topography, and Time

The correct answer is Parent material, Climate, Organisms, Topography, and Time. The five factors of soil formation, identified by Hans Jenny and others, are: Parent material (the rock from which soil forms), Climate (temperature and rainfall determine weathering rates), Organisms (plants, animals, and microbes add organic matter), Topography (slope affects erosion and drainage), and Time (soil formation is a very slow process taking hundreds to thousands of years). These five factors interact to produce the diverse range of soil types found in India and around the world. This topic is frequently tested in competitive examinations such as RRB NTPC, SSC, and UPSC.

Correct Answer: C. Upland terraces of the Indo-Gangetic plains

Kankar-bearing Bangar alluvial soils are most commonly found in the upland terraces (higher elevation areas away from river channels) of the Indo-Gangetic plains. In these areas, the old alluvial deposits are no longer regularly renewed by floods, and evaporation concentrates calcium carbonate, which precipitates as Kankar nodules at depth. This is common in the upland areas of UP, Bihar, and Punjab. The Kankar layer can restrict root growth and water movement in these soils.