Climate for Horticultural Crops

1. Introduction

• Climate is one of the most decisive factors determining the distribution, growth, yield, and quality of horticultural crops.
  Unlike field crops, horticultural crops are highly sensitive to temperature, rainfall, humidity, and other climatic parameters.
• Therefore, successful horticultural production depends on selecting the right crop for the right climate — a principle essential for sustainable agriculture.

2. Definition of Climate

• “Climate is the average pattern of weather conditions (temperature, rainfall, humidity, light, and wind) observed in a particular region over a long period of time (generally 30 years or more).”
• Weather is short-term (daily changes), while climate is long-term and governs the suitability of crops in an area.

3. Importance of Climate in Horticulture

• Determines crop adaptability — tropical, subtropical, temperate, or arid species.
• Affects growth, flowering, and fruiting behavior.
• Influences fruit quality — size, color, sugar, acidity, flavor.
• Affects incidence of pests and diseases.
• Decides propagation and nursery management seasons.
• Determines post-harvest life and storage potential of produce.

Major Climatic Elements Affecting Horticultural Crops

• Temperature

Role:

• Regulates germination, flowering, pollination, and fruit ripening.
• Each crop has a minimum, optimum, and maximum temperature range.

Temperature thresholds:

• Minimum: Below which growth stops
• Optimum: Best for physiological activities
• Maximum: Beyond which tissue damage occurs

Example:

• Mango flowering best occurs at 20–25°C with dry weather.
• Banana requires uniform warm climate (optimum 27°C).
• Apple and pear need chilling (below 7°C) for proper bud break.

• Rainfall

Role: Influences crop distribution, irrigation planning, and disease incidence. Excess or deficient rainfall affects flowering, fruiting, and quality.

Rainfall distribution is more important than total quantity — Uneven rain causes soil erosion and disease spread (e.g., anthracnose in mango).

• Humidity

Role:

• Influences transpiration, disease occurrence, fruit set, and quality.
• High humidity = lush growth but more fungal diseases.
• Low humidity = small fruits, cracking (e.g., litchi, pomegranate).

• Light (Solar Radiation and Day Length)

Role: Affects photosynthesis, flowering, color, and sugar accumulation. Determines photoperiodic response of crops.

Examples:

• Onion bulb formation occurs only in long days.
• Chrysanthemum flowers only under short days.
• Apple color development requires bright sunlight and cool nights.

• Wind

Role: Strong winds cause flower and fruit drop, mechanical injury, and pollination failure. Dry winds increase transpiration and desiccation.

Examples:

• In banana, strong wind causes pseudostem breakage.
• In papaya, winds cause fruit drop.

Wind Protection Measures:

• Windbreaks: Casuarina, Eucalyptus, Glyricidia along orchard borders.
• Shelterbelts: Multiple rows of trees planted to reduce wind velocity.
• Staking: Supporting tall plants like tomato, papaya, or chrysanthemum.

• Frost

Effects:

• Damages tropical crops (banana, papaya, citrus, guava).
• Kills young shoots and flowers; blackens leaves and fruits.

Sensitive crops: Papaya, banana, tomato, citrus.
Hardy crops: Apple, peach, plum, ber, aonla.

Preventive Measures:

• Smoking (creating a warm layer near surface).
• Sprinkler irrigation during frost night.
• Wind machines for air circulation.
• Planting hardy rootstocks.
• Delaying pruning until after frost risk.

• Altitude: Altitude affects temperature, radiation, and humidity.

As altitude increases, temperature decreases (~0.6°C per 100 m).

5. Climatic Zones for Horticultural Crops in India

India has diverse climatic regions, allowing cultivation of almost all horticultural crops.

6. Crop Distribution According to Climate

7. Effect of Climate on Quality of Horticultural Produce

8. Climate and Crop Suitability Examples

9. India’s Agro-Climatic Advantage in Horticulture

• India has 15 agro-climatic regions, allowing cultivation of diverse horticultural crops — from tropical mango to temperate apple.
• India ranks:
  • 2nd in world in fruit & vegetable production.
  • 1st in mango, banana, and okra production.

Key states by climatic suitability:

• Tropical: Maharashtra, Tamil Nadu, Kerala
• Subtropical: Uttar Pradesh, Bihar, Madhya Pradesh
• Temperate: Himachal Pradesh, Jammu & Kashmir, Uttarakhand
• Arid: Rajasthan, Gujarat
• Coastal: Odisha, Andhra Pradesh, Goa