Weather elements and their influence on different crops One Liner

Sun and Solar Radiation:

1. The Sun is the prime source of energy for Earth.
2. The Sun is about 1.39 million km in diameter.
3. It rotates on its axis approximately every 27 days at the equator.
4. The average distance between the Sun and Earth is about 149.64 million km.
5. The Sun’s surface temperature is 5462 K.
6. Every minute, the Sun radiates approximately 56 × 10^26 calories of energy.
7. The mass of the Sun has a density 80-100 times that of water.
8. The Sun’s energy is primarily due to hydrogen fusion into helium.
9. 99% of the energy received by Earth comes from the Sun.
10. Insolation is the electromagnetic energy radiated by the Sun into space.
11. Solar constant refers to the energy received on a unit area at Earth’s surface.
12. The solar constant fluctuates by about ±3.5% depending on the Earth’s distance from the Sun.
13. Albedo refers to the reflectivity of Earth’s surface, affecting radiation absorption.
14. Earth’s surface absorbs 35% of solar radiation as UV and visible light and 65% as infrared radiation.
15. Albedo varies by time of day, season, and surface characteristics.
16. Vegetation typically has an albedo of 10-40%, affecting energy absorption.
17. Clouds can reflect up to 55% of solar radiation.
18. Radiation balance is the difference between incoming and outgoing radiation at Earth’s surface.
19. Solar radiation is absorbed, reflected, and transmitted based on surface properties.
20. The visible spectrum of sunlight is crucial for plant growth and photosynthesis.

Solar Radiation and Crops:

21. UV radiation is chemically active but generally low in its impact on plant growth.
22. Infrared radiation (IR) affects plant temperature but is typically harmless when water vapor is present.
23. Light is essential for photosynthesis in plants.
24. Poor light conditions can cause plant abnormalities.
25. Plants rely on light intensity, quality, and duration for normal growth.
26. Light influences tillering, stability, and the strength of plant structures.
27. Adequate light boosts leaf size and root development in crops.
28. Maize plants require intense radiation during their third month of growth.
29. Rice needs significant radiation 25 days before flowering.
30. Barley’s critical radiation period is during flowering.

Heat Transfer and Radiation Laws:

31. Heat transfer occurs via conduction, convection, and radiation.
32. Conduction transfers heat through matter without movement of the substance.
33. Convection involves heat transfer through molecular movement in fluids.
34. Radiation transfers energy without a medium, such as from the Sun to Earth.
35. Solar radiation is a short-wave energy, while Earth emits long-wave radiation.
36. Emissivity refers to how efficiently a surface emits radiation.
37. Blackbody radiation is emitted by an ideal surface that absorbs and emits all radiation.
38. Stefan-Boltzmann’s law states radiation intensity is proportional to the fourth power of the absolute temperature.
39. Kirchhoff’s law states a good absorber of radiation is also a good emitter.
40. Planck’s law describes radiation emitted by a blackbody at a specific temperature.
41. Wien’s Displacement law shows the maximum wavelength of radiation is inversely proportional to temperature.
42. The intensity of solar radiation is highest in the blue-green visible light range.

Absorptivity and Reflectivity:

43. Absorptivity is the ratio of absorbed radiation to incident radiation.
44. The absorptivity of a perfect black body is unity (1).
45. Reflectivity is the ratio of reflected radiation to incident radiation.
46. Albedo refers to the percentage of reflected radiation, affected by surface color and composition.
47. Albedo is highest during winter and at sunrise or sunset.
48. Light-colored surfaces have higher reflectivity compared to dark ones.
49. Clouds and snow have a higher albedo compared to vegetation and soil.

Outgoing Long-Wave Radiation:

50. After being heated by the Sun, Earth emits long-wave infrared radiation.
51. Earth’s surface temperature is about 285 K (12°C).
52. 99% of Earth’s radiation is in the infrared (IR) range.
53. The atmosphere absorbs about 90% of outgoing radiation.
54. Water vapor absorbs radiation between 5.3 to 7.7 μm and beyond 20 μm.
55. CO2 absorbs radiation in the range of 13.1 to 16.9 μm.
56. Ozone absorbs radiation between 9.4 to 9.8 μm.
57. Clouds absorb radiation across all wavelengths.
58. The “atmospheric window” allows some long-wave radiation to escape into space between 8.5 to 11 μm.
59. Counter-radiation from the atmosphere prevents excessive cooling at night.

Temperature and Heat:

60. Temperature measures the average speed of atoms and molecules.
61. Kinetic energy is energy of motion, related to temperature.
62. Heat is the internal energy transfer due to temperature differences.
63. Sensible heat is the heat that can be measured with a thermometer.
64. Latent heat is energy required for a substance to change state, such as evaporation or condensation.
65. The latent heat of evaporation for water is 600 calories per gram.
66. The latent heat of fusion (from liquid to solid) for water is 80 calories per gram.

Heat Balance and Energy:

67. Energy balance is the difference between energy input and output in an environment.
68. Net radiation drives processes like evaporation, heating air, and soil heat flux.
69. The net radiation is essential for evapotranspiration and photosynthesis in crops.
70. Energy from net radiation is used by crops for growth, respiration, and photosynthesis.
71. Latent heat flux (LE) is essential for plant water uptake and growth.
72. Sensible heat flux (H) influences air temperature and plant transpiration.
73. Soil heat flux (G) is important for root development in crops.
74. Radiation balance affects crop health by influencing soil moisture and air temperature.
75. Evapotranspiration is driven by net radiation and affects crop water needs.

Plant Growth and Light:

76. Light intensity, quality, and duration are essential for photosynthesis.
77. Insufficient light leads to abnormal plant growth and reduced yields.
78. Crops like rice, maize, and barley require specific light levels during their growing seasons.
79. Light influences tillering and branching in cereals.
80. Light stress can reduce crop yield and quality.
81. Plants can adjust their light absorption based on seasonal and daily radiation variations.
82. The angle of sunlight affects photosynthesis efficiency.
83. Crop canopy structure and light penetration are influenced by light intensity.

Climate and Weather Effects:

84. Soil temperature is influenced by solar radiation and air temperature.
85. Rainfall and cloud cover can reduce solar radiation, affecting crop growth.
86. Wind speed can influence evapotranspiration and cooling of plants.
87. Increased cloudiness reduces solar radiation reaching plant surfaces.
88. Humidity influences the absorption of infrared radiation by crops.
89. Temperature extremes can damage crops, affecting photosynthesis and growth.
90. Frost damage to crops is due to reduced temperature below freezing points.

Miscellaneous:

91. The color of the sky is due to Rayleigh scattering, which affects blue light more than red.
92. Red sunsets are due to longer atmospheric paths, scattering shorter wavelengths.
93. Infrared radiation is important for maintaining crop temperature during night-time.
94. Solar radiation is critical during the reproductive stage of many crops.
95. UV radiation is absorbed by the ozone layer, protecting plants from damage.
96. Vegetative growth depends on a balance of radiation, temperature, and water.
97. Plants exhibit photoperiodism, responding to the length of day and night.
98. Excessive radiation during drought periods can stress crops.
99. Light quality affects the rate of photosynthesis, with red light being most effective.
100. Solar radiation helps crops produce energy and sustains the Earth’s ecosystem.

Disposition of Solar Radiation

1. 25% of solar radiation is reflected back into space by clouds.
2. Reflection by clouds is greater in middle and high latitudes and lesser in subtropical regions.
3. 6% of solar radiation is reflected by the air, dust, and water vapor.
4. 30% of solar radiation is scattered downward, predominantly in shorter wavelengths.
5. Shorter wavelengths (violet and blue) scatter more than longer wavelengths (red).
6. 17% of solar radiation is absorbed by the atmosphere.
7. Oxygen absorbs extreme UV wavelengths (0.12 to 0.6 μm).
8. Ozone (O3) absorbs UV radiation between 0.2 and 0.32 μm and visible light between 0.44 and 0.7 μm.
9. Water vapor (H2O) absorbs near-infrared radiation at wavelengths like 0.93, 1.13, and 1.42 μm.
10. CO2 absorbs infrared radiation, especially at 2.7 μm.
11. About 50% of solar radiation reaches Earth’s surface after reflection, scattering, and absorption.

Light and its Effects on Crop Production

Light Intensity

12. Light intensity is measured in lux or foot-candles.
13. 1 meter-candle equals 1 lux.
14. 1 foot-candle equals 10.764 lux.
15. Lux meters measure light intensity.
16. About 1% of light energy is converted into biochemical energy in plants.
17. Very low light intensity reduces the rate of photosynthesis.
18. High light intensity increases respiration and water loss through transpiration.
19. Solarization, caused by high light intensity, oxidizes cell contents.
20. Light intensity decreases exponentially as it passes through layers of leaves.
21. At ground level, light intensity often falls below the compensation point.
22. Sciophytes (shade-loving plants) grow well under low light conditions.
23. Hetrophytes (sun-loving plants) need high light intensity for optimal growth.

Quality of Light

24. Light includes wavelengths from 0.39 to 0.76 μm.
25. Violet light has wavelengths between 400 and 435 nm.
26. Blue light spans from 435 to 490 nm.
27. Green light ranges from 490 to 574 nm.
28. Yellow light is between 574 and 595 nm.
29. Orange light lies between 595 and 626 nm.
30. Red light ranges from 626 to 750 nm.
31. Plants absorb violet-blue and orange-red light most effectively.
32. Shorter wavelengths beyond violet and longer wavelengths beyond red can harm plants.

Duration of Light

33. Duration of light affects canopy development and crop yield.
34. Photoperiodism refers to plant responses to day length.
35. Long-day plants require a photoperiod longer than 12 hours for proper development.
36. Short-day plants thrive under a photoperiod shorter than 12 hours.
37. Day-neutral plants, such as tomatoes, are unaffected by day length.
38. Long-day plants flower in response to longer days and shorter nights.
39. Short-day plants flower under shorter days and longer nights.
40. The photoperiod influences floral initiation, bulb and rhizome production.

Direction of Light

41. The direction of sunlight affects plant organ orientation.
42. Plants in temperate regions grow better on southern slopes due to more sunlight.
43. Phototropism is the orientation of plant parts toward light.
44. Photomorphogenesis refers to morphological changes due to light exposure.

Air Temperature and its Effects on Crop Production

Temperature Basics

45. Temperature measures the molecular speed of substances.
46. Heat is the energy resulting from molecular motion.
47. Conduction is heat transfer through direct contact.
48. Convection involves heat transfer through the movement of fluids or gases.
49. Radiation is heat transfer without a medium, through electromagnetic waves.

Factors Affecting Air Temperature

50. Latitude significantly impacts the time of maximum and minimum temperatures.
51. Altitude causes a decrease in temperature with height due to lower air density.
52. Land and water surfaces absorb and release heat differently, causing temperature variations.
53. Ocean currents moderate temperatures by moving warm water toward cool regions.
54. Prevailing winds can alter surface temperatures on land and water.
55. Cloudiness affects daytime and nighttime temperatures by blocking sunlight.
56. Mountain barriers create temperature differences between valleys and hilltops.
57. The nature of a region’s surface influences local temperature.
58. Relief features, such as mountains, influence local temperature distribution.

Diurnal and Seasonal Temperature Variation

59. Minimum temperature typically occurs around sunrise.
60. Maximum temperature is generally reached between 1300-1400 hrs.
61. The diurnal range is the difference between maximum and minimum daily temperatures.
62. Clear days have a higher diurnal temperature range than cloudy days.
63. Soil and its coverage impact the diurnal temperature range.
64. Daily mean temperature is the average of the day’s maximum and minimum temperatures.
65. In the northern hemisphere, January is the coldest month, and July is the warmest.
66. Seasonal temperature variations depend on latitude and altitude.

Horizontal and Vertical Temperature Distribution

67. Isotherms connect areas with equal temperature.
68. Temperature decreases from the equator to the poles.
69. Land warms and cools faster than water, influencing regional temperatures.
70. Mountain ranges can block air masses, influencing temperature patterns.
71. Local temperature distribution can be affected by topographical features like valleys.

Temperature Inversion

72. Temperature inversion occurs when air temperature increases with height.
73. Inversion may happen when the ground cools faster than the air above it.
74. A warm air layer above cold air can create a temperature inversion.
75. Temperature inversions hinder vertical mixing of air, affecting weather patterns.
76. Temperature inversions contribute to fog formation and reduced visibility.
77. Inversions affect air navigation and the spread of pollutants.

Heat Units and Growing Degree Days

78. Growing Degree Days (GDD) measure the warmth of the growing season.
79. GDD is the sum of daily temperature values above a base threshold.
80. The threshold temperature, below which no growth occurs, varies by crop.
81. Base temperatures typically range from 4.5 to 12.5°C, with 6.0°C being most common.
82. GDD is calculated by averaging the daily maximum and minimum temperatures.
83. GDD can predict crop growth, harvest times, and labor needs.
84. It helps forecast crop yield and quality.
85. The concept aids in determining the suitability of crops in various regions.

Importance of GDD

86. GDD is essential for guiding agricultural operations and planting schedules.
87. It helps forecast the likely harvest dates of crops.
88. It assists in assessing labor needs for agricultural tasks.
89. GDD aids in determining the feasibility of introducing new crops.
90. The GDD method predicts successful crop growth in a given area.
91. Heat units provide insight into crop growth potential and environmental suitability.

Influence of Temperature on Crop Growth

92. High temperatures can cause heat stress, reducing crop yields.
93. Low temperatures may delay germination and reduce growth rates.
94. Temperature fluctuations can impact plant physiology and productivity.
95. Seasonal temperature extremes influence crop selection and adaptation.
96. Temperature inversions can cause frost damage during growing seasons.
97. Consistent temperatures during the growing season promote steady crop growth.
98. Cold temperatures can affect the quality of harvested crops.
99. Temperature extremes can reduce photosynthesis rates in sensitive plants.
100. Managing temperature through techniques like irrigation and shading can optimize crop production.

Heat Injuries:

1. Thermal death point is the temperature at which plant cells are killed, generally between 50-60°C.
2. Aquatic and shade-loving plants die at lower temperatures around 40°C.
3. High temperatures lead to plant desiccation, disrupting physiological processes.
4. High heat increases respiration, depleting reserve food in plants.
5. Sunclad injury is caused by high day temperatures and low night temperatures affecting tree barks.
6. Stem griddle occurs due to high soil temperatures, leading to plant death, especially in cotton seedlings.
7. Plant death in stem griddle is due to the destruction of conductive tissues.
8. Seedlings in sandy soil are particularly vulnerable to high soil temperatures (over 60°C).
9. High temperatures disrupt photosynthesis and respiration in plants.
10. High soil temperature in young seedlings can cause severe damage.

Cold Injuries:

11. Chilling injury occurs when hot-climate plants are exposed to low temperatures.
12. Sugarcane, sorghum, and maize are susceptible to chlorotic bands when exposed to temperatures below 20°C.
13. Freezing injury causes ice crystals to form in plant cells, damaging protoplasm and leading to cell death.
14. Frost damage in crops like potatoes and tea is an example of freezing injury.
15. Suffocation occurs when ice or snow prevents oxygen entry, halting root respiration.
16. Heaving occurs when frozen soil lifts plants, causing damage in temperate regions.
17. Ice crystals in soil contribute to mechanical soil lifting, causing plant root exposure.
18. Plants in temperate climates are more susceptible to root suffocation under snow.

Role of Temperature in Crop Production:

19. Temperature directly influences the distribution of crop plants and vegetation.
20. Air temperature affects all stages of crop growth, from germination to reproduction.
21. Leaf production and expansion are controlled by temperature.
22. Temperature influences the diffusion rates of gases and liquids.
23. The solubility of substances in plants is temperature-dependent.
24. Biochemical reactions in plants double with every 10°C rise in temperature.
25. Equilibrium of systems and compounds in plants is affected by temperature.
26. Temperature influences the stability of plant enzymatic systems.
27. Most crops grow optimally between 10°C and 40°C, with maximum dry matter produced at 20-30°C.
28. High temperatures and humidity increase the risk of pest and disease infestations.
29. High night temperatures increase plant respiration and metabolism.
30. Temperature changes can lengthen or shorten crop durations.
31. Cardinal temperatures (minimum, optimum, and maximum) define the growth limits for crops.

Cardinal Temperatures for Specific Crops:

32. Wheat and Barley: Min: 0-5°C, Optimum: 25-31°C, Max: 31-37°C.
33. Sorghum: Min: 15-18°C, Optimum: 31-36°C, Max: 40-42°C.

Thermoperiodism:

34. Thermoperiodism refers to plant responses to regular temperature fluctuations.

Soil Temperature:

35. Soil temperature is a critical factor influencing crop growth and root development.
36. The soil temperature affects seed germination and root development.
37. Temperature of the soil directly impacts plant uptake of water and nutrients.
38. Extreme soil temperatures can damage plants and hinder their growth.
39. Soil microorganisms are also affected by soil temperature.
40. Warm soils favor faster mineralization of nitrogen.
41. Soil moisture content affects soil temperature variations.
42. Soil structure and composition determine the extent of temperature fluctuations.

Factors Affecting Soil Temperature:

43. Solar radiation directly influences soil temperature.
44. Winds and air convection heat up soil by conducting heat from the atmosphere.
45. Evaporation from the soil can cool it, while condensation heats the soil.
46. Rainfall can either cool or warm the soil, depending on its temperature.
47. Soil aspect (orientation) affects the amount of sunlight it receives, influencing temperature.
48. Soils with a rough surface absorb more solar radiation than smooth soils.
49. Sandy soils warm up faster than clay soils due to their lower heat capacity.
50. Soil moisture levels impact soil temperature, with moist soils remaining cooler than dry soils.
51. Tillage practices can modify soil temperature by altering surface properties.
52. Organic matter increases heat capacity and moisture retention in soils.
53. Moist soils have more uniform temperature profiles than dry soils.

Variations in Soil Temperature:

54. Soil temperature varies daily and seasonally.
55. Daily temperature fluctuations are most noticeable at the soil surface.
56. At greater depths (e.g., 20 cm), diurnal temperature changes are less pronounced.
57. On sunny days, bare soil surfaces are often hotter than the air temperature.
58. Soil temperature peaks after the air temperature due to thermal lag.
59. Seasonal temperature changes are more pronounced in tropical and subtropical regions.
60. Soil freezes more deeply in winter depending on the severity and duration of cold conditions.
61. Soil cooling in winter is influenced by the plant canopy, which reduces temperature fluctuations.

Humidity and Crop Production:

62. Humidity is the amount of water vapor present in the atmosphere.
63. Absolute humidity refers to the actual mass of water vapor per unit volume of air.
64. Specific humidity is the mass of water vapor per unit mass of moist air.
65. Mixing ratio refers to the mass ratio of water vapor to dry air.
66. Relative humidity is the ratio of current water vapor content to the maximum possible content at a given temperature.
67. Dew point temperature is the temperature at which air becomes saturated with water vapor.
68. Vapour pressure deficit measures the difference between saturated and actual vapor pressures.
69. High humidity increases plant transpiration.
70. Humidity affects plant water potential and overall growth.
71. High humidity reduces crop water requirements by limiting evapotranspiration.
72. Very high or low relative humidity can reduce crop yields.
73. Humidity plays a role in fungal and bacterial disease outbreaks in crops.
74. Crops like maize, sorghum, and sugarcane benefit from high humidity.
75. Crops like tobacco and sunflower suffer from high humidity.
76. Relative humidity is highest at sunrise and lowest in the afternoon.
77. Humidity is highest at the equator and lowest at the poles.
78. Absolute humidity is higher in the afternoon than at sunrise.
79. Diurnal temperature variations are generally smaller in desert regions.
80. High humidity can prolong crop survival during moisture stress.
81. Moderate humidity, typically above 40%, is ideal for most crops.

Humidity Variations:

82. Relative humidity is highest at dawn and lowest around 2-3 p.m.
83. Humidity is affected by temperature, with colder air holding less moisture.
84. Changes in humidity directly affect evapotranspiration rates.
85. The diurnal variation in humidity is smaller in desert climates compared to tropical regions.
86. Absolute humidity is influenced by latitude, being higher in tropical regions.
87. Low humidity leads to increased evaporation from plant surfaces.
88. Very high humidity can lead to mold growth, affecting crop yields.
89. Variations in relative humidity influence plant water uptake and stress levels.
90. High humidity can help crops survive in regions with limited water supply.

Impact on Crop Growth:

91. High humidity promotes fungal diseases like blight in potatoes.
92. Humidity influences the growth of pests like thrips and jassids.
93. The optimal humidity for crops varies by species and growth stage.
94. High humidity at grain filling stages can reduce crop yields.
95. Crops such as wheat benefit from moderate humidity for optimal growth.
96. Low humidity accelerates transpiration, increasing water demand.
97. High humidity at night can inhibit respiration in some crops.
98. Humidity is a key determinant in crop water requirements and transpiration rates.
99. Variations in humidity can influence pest and disease dynamics in crops.
100. The balance of humidity, temperature, and soil moisture is crucial for maximizing crop production.