Fundamentals of Agronomy-4

By Skumar

 

Fundamentals of Agronomy-4

PART A: Water Management 

1. Water management in agriculture mainly aims at

A. Increasing soil temperature
B. Efficient use of available water
C. Increasing weed growth
D. Reducing fertilizer use

✅ Answer: B
📌 Explanation: Water management ensures optimum use of water for maximum crop yield and efficiency.

2. The largest source of freshwater on Earth is

A. Rivers
B. Lakes
C. Groundwater
D. Glaciers and ice caps

✅ Answer: D
📌 Explanation: About 68–69% of freshwater is stored in glaciers and ice caps.

3. Major source of irrigation water in India is

A. Canals
B. Tanks
C. Groundwater
D. Rivers

✅ Answer: C
📌 Explanation: Groundwater contributes more than 60% of irrigation in India.

4. Which irrigation method has highest water use efficiency?

A. Flood irrigation
B. Furrow irrigation
C. Sprinkler irrigation
D. Drip irrigation

✅ Answer: D
📌 Explanation: Drip irrigation minimizes losses due to evaporation and runoff.

5. Consumptive use of water refers to

A. Total rainfall received
B. Water used for irrigation
C. Water lost by evapotranspiration
D. Water stored in soil

✅ Answer: C
📌 Explanation: Consumptive use includes transpiration and evaporation losses.

6. Crop water requirement is the sum of

A. Rainfall + runoff
B. Evaporation + transpiration
C. Transpiration + percolation
D. Irrigation + rainfall

✅ Answer: B
📌 Explanation: Crop water requirement = Evapotranspiration (ET).

7. Critical stage of irrigation means

A. Stage of maximum rainfall
B. Stage sensitive to water stress
C. Harvesting stage
D. Maturity stage

✅ Answer: B
📌 Explanation: Moisture stress at critical stages causes maximum yield loss.

8. Most critical stage for irrigation in wheat

A. Tillering
B. Jointing
C. Crown root initiation
D. Milk stage

✅ Answer: C
📌 Explanation: CRI stage (20–25 DAS) is the most critical in wheat.

9. Most critical irrigation stage in rice

A. Seedling
B. Tillering
C. Panicle initiation
D. Ripening

✅ Answer: C
📌 Explanation: Water stress at panicle initiation reduces grain number.

10. Water logging affects crop mainly due to

A. High moisture
B. Poor aeration
C. Nutrient toxicity
D. Soil cracking

✅ Answer: B
📌 Explanation: Water logging reduces oxygen availability to roots.

11. Duty of water is defined as

A. Area irrigated per unit discharge
B. Volume of water applied
C. Depth of irrigation
D. Time of irrigation

✅ Answer: A
📌 Explanation: Duty = Area irrigated by unit flow during crop period.

12. Delta of irrigation means

A. Time of irrigation
B. Total depth of water required
C. Area irrigated
D. Frequency of irrigation

✅ Answer: B
📌 Explanation: Delta is the total depth of water needed during crop growth.

13. Irrigation scheduling is based on

A. Calendar days
B. Crop growth stage
C. Soil moisture status
D. All of the above

✅ Answer: D
📌 Explanation: Scientific scheduling considers crop, soil, and climate.

14. Field capacity represents

A. Maximum water soil can hold
B. Water retained after gravitational drainage
C. Water unavailable to plants
D. Saturation point

✅ Answer: B
📌 Explanation: Field capacity is moisture left after free drainage.

15. Permanent wilting point occurs when

A. Soil is saturated
B. Plant cannot recover turgidity
C. Capillary water increases
D. Hygroscopic water increases

✅ Answer: B
📌 Explanation: At PWP plants fail to recover even in humid conditions.

16. Available soil moisture lies between

A. Saturation and FC
B. FC and PWP
C. PWP and hygroscopic point
D. Saturation and PWP

✅ Answer: B
📌 Explanation: Available water = FC – PWP.

17. Water use efficiency is

A. Yield / rainfall
B. Yield / irrigation
C. Yield / evapotranspiration
D. Irrigation / yield

✅ Answer: C
📌 Explanation: WUE expresses yield per unit water used.

18. Pan evaporation is used to estimate

A. Rainfall
B. Transpiration
C. Evaporation
D. Evapotranspiration

✅ Answer: D
📌 Explanation: Pan evaporation is converted to ET using coefficients.

19. Crop coefficient (Kc) relates

A. ET₀ and ETc
B. Rainfall and runoff
C. Soil and crop
D. Yield and water

✅ Answer: A
📌 Explanation: ETc = Kc × ET₀.

20. Most drought-resistant crops

A. Rice
B. Wheat
C. Sorghum
D. Sugarcane

✅ Answer: C
📌 Explanation: Sorghum has deep roots and waxy leaves.

21. Anti-transpirants are used to

A. Increase transpiration
B. Reduce transpiration
C. Increase photosynthesis
D. Improve germination

✅ Answer: B
📌 Explanation: They reduce water loss under drought.

22. Mulching helps in

A. Increasing evaporation
B. Reducing soil moisture
C. Conserving soil moisture
D. Increasing runoff

✅ Answer: C
📌 Explanation: Mulch reduces evaporation and improves moisture retention.

23. Life irrigation refers to

A. Regular irrigation
B. Emergency irrigation
C. Protective irrigation
D. Flood irrigation

✅ Answer: B
📌 Explanation: Given to save crop during severe moisture stress.

24. Protective irrigation is common in

A. Irrigated farming
B. Rainfed farming
C. Dry farming
D. Garden land

✅ Answer: B
📌 Explanation: Rainfed crops receive limited irrigation during dry spells.

25. Which crop requires standing water?

A. Wheat
B. Rice
C. Maize
D. Gram

✅ Answer: B
📌 Explanation: Rice tolerates anaerobic soil conditions.

26. Conjunctive use of water means

A. Use of rainwater only
B. Use of surface water only
C. Combined use of surface & groundwater
D. Recycling wastewater

✅ Answer: C
📌 Explanation: Conjunctive use optimizes water resources.

27. Which soil has highest water holding capacity?

A. Sandy
B. Loamy
C. Clayey
D. Gravel

✅ Answer: C
📌 Explanation: Clay soils have finer pores.

28. Deep percolation loss is highest in

A. Clay soil
B. Loam soil
C. Sandy soil
D. Peaty soil

✅ Answer: C
📌 Explanation: Sandy soils allow rapid downward movement of water.

29. Frequency of irrigation depends mainly on

A. Crop type
B. Soil type
C. Climate
D. All of the above

✅ Answer: D
📌 Explanation: All factors influence irrigation interval.

30. Highest evapotranspiration occurs in

A. Winter
B. Rainy season
C. Summer
D. Autumn

✅ Answer: C
📌 Explanation: High temperature and radiation increase ET.

31. Skipping irrigation at which stage least affects yield?

A. Critical stage
B. Vegetative stage
C. Reproductive stage
D. Flowering stage

✅ Answer: B
📌 Explanation: Vegetative stage is relatively less sensitive.

32. Water stress during flowering causes

A. Lodging
B. Reduced tillers
C. Poor pollination
D. Delayed maturity

✅ Answer: C
📌 Explanation: Moisture stress affects pollen viability.

33. Scheduling irrigation by IW/CPE ratio uses

A. Soil moisture
B. Pan evaporation
C. Crop growth
D. Rainfall

✅ Answer: B
📌 Explanation: IW/CPE is based on cumulative pan evaporation.

34. High frequency irrigation is preferred in

A. Clay soil
B. Sandy soil
C. Black soil
D. Alluvial soil

✅ Answer: B
📌 Explanation: Sandy soil has low water holding capacity.

35. Water requirement is highest in

A. Pulses
B. Oilseeds
C. Cereals
D. Sugarcane

✅ Answer: D
📌 Explanation: Sugarcane is a long-duration, high-water crop.

🔹 PART B: Soil Moisture Constants (Q.36–50)

36. Gravitational water is

A. Available to plants
B. Held by capillary forces
C. Drains due to gravity
D. Hygroscopic water

✅ Answer: C
📌 Explanation: Gravitational water drains quickly and is unavailable.

37. Capillary water is

A. Unavailable to plants
B. Available to plants
C. Toxic
D. Lost immediately

✅ Answer: B
📌 Explanation: Capillary water is the main source for plants.

38. Hygroscopic water is

A. Absorbed by roots
B. Held tightly by soil particles
C. Capillary water
D. Gravitational water

✅ Answer: B
📌 Explanation: It is unavailable due to strong adsorption.

39. Soil saturation point occurs when

A. All pores are filled with air
B. All pores are filled with water
C. Only capillary pores filled
D. Only macro pores filled

✅ Answer: B
📌 Explanation: Saturation means complete pore filling.

40. Field capacity is expressed in terms of

A. % soil moisture
B. Depth of water
C. Weight of soil
D. Soil texture

✅ Answer: A
📌 Explanation: FC is measured as % moisture content.

41. Permanent wilting point corresponds to

A. -0.33 bar
B. -1 bar
C. -15 bar
D. -33 bar

✅ Answer: C
📌 Explanation: PWP occurs at around -15 bar tension.

42. Available water capacity is highest in

A. Sandy soil
B. Clay soil
C. Loam soil
D. Gravel

✅ Answer: C
📌 Explanation: Loam soils balance pore size distribution.

43. Soil moisture tension increases as

A. Moisture increases
B. Moisture decreases
C. Texture becomes coarser
D. Porosity increases

✅ Answer: B
📌 Explanation: Drier soil holds water more tightly.

44. Capillary rise is maximum in

A. Sandy soil
B. Clay soil
C. Gravel
D. Loam

✅ Answer: B
📌 Explanation: Fine pores allow higher capillary rise.

45. Wilting coefficient refers to

A. Field capacity
B. Saturation point
C. Permanent wilting point
D. Available water

✅ Answer: C
📌 Explanation: Wilting coefficient equals PWP.

46. Soil moisture available to plants depends on

A. Texture
B. Structure
C. Organic matter
D. All of the above

✅ Answer: D
📌 Explanation: All influence water retention.

47. Maximum water retention is found in

A. Sandy soil
B. Clay soil
C. Silty soil
D. Gravel

✅ Answer: B
📌 Explanation: Clay has highest total porosity.

48. Soil moisture constants were proposed by

A. Mitscherlich
B. Gardner
C. Veihmeyer & Hendrickson
D. Liebig

✅ Answer: C
📌 Explanation: They defined FC and PWP concepts.

49. Plant-available water is highest between

A. Saturation & FC
B. FC & PWP
C. PWP & hygroscopic
D. Saturation & PWP

✅ Answer: B
📌 Explanation: Only water between FC and PWP is usable.

50. Which water is lost first after irrigation?

A. Capillary
B. Hygroscopic
C. Gravitational
D. Available

✅ Answer: C
📌 Explanation: Gravitational water drains rapidly.


Comments

Post a Comment

Principles of Agronomy

Smart Irrigation Management in Orchards for Higher Profit & Water Saving

By Skumar
Image
  Smart Irrigation Management in Orchards for Higher Profit & Water Saving Orchard farming—whether it involves mango, citrus, apple, or pomegranate—depends heavily on efficient irrigation management. Water is not just a basic input; it directly influences tree growth, fruit quality, yield consistency, and long-term soil health. Poor irrigation practices can lead to root diseases, nutrient leaching, and reduced productivity, while well-planned irrigation enhances profitability and sustainability. This final upgraded blog includes advanced strategies, Indian government schemes, monetization opportunities, and expert insights to make it SEO-rich, practical, and income-generating . Also Read:  Propagation Methods in Fruit Crops: Complete ICAR Guide for Students, Farmers & Exams Understanding Water Requirements in Orchards Drip Irrigation  Each fruit tree has different water needs depending on: Tree age (young vs mature) Soil type (sandy, loamy, clay) Climate conditio...
Read more

Climatic Requirements for Fruit Cultivation | Temperature, Rainfall & Climate Factors Explained

By Skumar
Image
Climatic Requirements for Fruit Cultivation | Temperature, Rainfall & Climate Factors Explained Fruit cultivation is an important branch of Horticulture that deals with the growing of fruit crops for food, nutrition, and economic benefits. Climate plays a vital role in determining the growth, flowering, fruiting, and quality of fruits. Every fruit crop has specific climatic requirements such as temperature, rainfall, humidity, sunlight, and wind conditions. If the climate is favorable, fruit plants grow well and produce high-quality fruits. However, unfavorable climatic conditions may reduce yield and quality. Understanding the climatic requirements of fruit crops is essential for farmers, agricultural students, and horticulture enthusiasts. Proper knowledge helps in selecting suitable fruit crops for a particular region and adopting the right cultivation practices. Also Read:  Classification of Fruit Crops in Horticulture (With Examples & MCQs) 1. Importance of Climate...
Read more

Training and Pruning in Fruit Crops: Techniques for Higher Yield, Better Quality & Healthy Orchards

By Skumar
Image
 Training and Pruning in Fruit Crops: Techniques for Higher Yield, Better Quality & Healthy Orchards Introduction Training and pruning are two of the most important orchard management practices that directly influence plant growth, fruit quality, and yield. Proper canopy management ensures better sunlight penetration, air circulation, and efficient use of nutrients. In modern agriculture, especially under high-density planting systems, training and pruning are essential for achieving maximum productivity and profitability . Also Read:  Systems of Planting in Fruit Crops Complete Guide with MCQs What is Training in Fruit Crops? Training is the practice of directing plant growth into a desired shape and structure, especially during the early stages of development. Objectives: Develop a strong framework Ensure maximum sunlight exposure Facilitate intercultural operations Prevent branch breakage Improve fruit quality What is Pruning? Pruning is the selective removal of unwant...
Read more