Agriculture and Rural Development

Correct answer: B

It is produced under conditions suitable for composting worms.

Correct answer: D

I is incorrect: Humus → Relatively stable decomposed organic matter. It improves nutrient retention and aspects of soil structure. II is incorrect: Nitrogen as a plant nutrient → Important component of proteins and chlorophyll. Deficiency often appears first as yellowing of older leaves.

Correct answer: A

It also participates in enzyme activity.

Correct answer: C

I is correct: Soil texture → Relative proportions of sand, silt and clay. Texture strongly influences water retention and aeration. II is incorrect: Cation exchange capacity → Capacity of soil to retain exchangeable positively charged ions. Clay and organic matter contribute to it.

Correct answer: D

Stable aggregates improve pore continuity and tilth.

Correct answer: C

I is correct: Green manuring → Incorporation of a green crop to improve soil. Leguminous green manures can add biologically fixed nitrogen. II is incorrect: Sulphur as a plant nutrient → Component of certain amino acids. Cysteine and methionine contain sulphur.

Correct answer: A

It participates in stomatal regulation and stress response.

Correct answer: C

I is incorrect: Farmyard manure → Decomposed mixture of animal dung, urine and bedding. It supplies organic matter and nutrients. II is incorrect: Vermicompost → Organic material processed with earthworm activity. It is produced under conditions suitable for composting worms.

Correct answer: D

Deficiency often appears first as yellowing of older leaves.

Correct answer: C

I is incorrect: Calcium as a plant nutrient → Important in cell walls and growing tissues. It contributes to cell-wall structure and membrane function. II is incorrect: Sulphur as a plant nutrient → Component of certain amino acids. Cysteine and methionine contain sulphur.

Correct answer: A

ATP and nucleic acids contain phosphorus.

Correct answer: A

I is correct: Nitrogen as a plant nutrient → Important component of proteins and chlorophyll. Deficiency often appears first as yellowing of older leaves. II is correct: Green manuring → Incorporation of a green crop to improve soil. Leguminous green manures can add biologically fixed nitrogen.

Correct answer: B

Cysteine and methionine contain sulphur.

Correct answer: A

I is correct: Nitrogen as a plant nutrient → Important component of proteins and chlorophyll. Deficiency often appears first as yellowing of older leaves. II is correct: Magnesium as a plant nutrient → Central atom in chlorophyll. It also participates in enzyme activity.

Correct answer: D

It contributes to cell-wall structure and membrane function.

Correct answer: C

I is incorrect: Phosphorus as a plant nutrient → Important in energy transfer and root development. ATP and nucleic acids contain phosphorus. II is incorrect: Potassium as a plant nutrient → Important in enzyme activation and water regulation. It participates in stomatal regulation and stress response.

Correct answer: D

I is incorrect: Terracing → Creating stepped cultivation surfaces on slopes. It reduces slope length and runoff velocity. II is incorrect: Drip irrigation → Frequent localised delivery near plant roots. It can reduce non-beneficial water losses when well managed.

Correct answer: A

It can disperse clay and reduce infiltration.

Correct answer: B

I is correct: Permanent wilting point → Water content below which plants cannot recover turgor under reference conditions. Water is held too tightly for adequate uptake. II is incorrect: Mulching → Covering the soil surface. It can reduce evaporation and moderate soil temperature.

Correct answer: A

I is incorrect: Sodicity → Excess exchangeable sodium affecting soil properties. It can disperse clay and reduce infiltration. II is correct: Furrow irrigation → Water flowing through channels between crop rows. Water infiltrates laterally and downward from the furrows.

Correct answer: D

It represents a useful upper reference for available soil water.

Correct answer: B

I is correct: Waterlogging → Excess water restricting air in the root zone. Oxygen shortage can damage roots. II is incorrect: Shelterbelt → Rows of trees reducing wind speed. It can limit wind erosion and protect crops.

Correct answer: D

Water is held too tightly for adequate uptake.

Correct answer: C

I is incorrect: Furrow irrigation → Water flowing through channels between crop rows. Water infiltrates laterally and downward from the furrows. II is correct: Drip irrigation → Frequent localised delivery near plant roots. It can reduce non-beneficial water losses when well managed.

Correct answer: D

It helps slow downslope water movement.