AGRONOMY LECTURE SERIES
Topic: Rice (Oryza sativa) - Production Technology
1. Introduction, Origin & Distribution
- Origin: Vavilov (1926) suggested India and Burma as the center of origin. Oldest specimens found in Hasthinapur (UP) dated 1000-750 B.C.
- Global Status: Rice is the world's leading food crop. India has the largest area (44.8 m ha) globally and ranks 2nd in production (after China).
- Economic Importance: Staple food for 60% of the world. It provides 22% of the world's calorie supply. Rice farming is the single largest use of land for food.
2. Soil & Climatic Requirements
Climatic Requirements
- Temperature: Hot and humid climate is best. Range: 21°C to 37°C.
- Critical Temps: Blooming (26.5-29.5°C) and Ripening (20-25°C).
- Photoperiod: Rice is a Short Day Plant (though many modern varieties are photo-insensitive).
Soil Requirements
- Texture: Clay or clay loams are most suited due to water retention.
- pH: Prefers acidic soils (pH 5.5 to 6.5). Tolerates alkalinity after gypsum treatment.
4. Cultural Practices
A. Nursery Management
- Seed Rate: Short duration (60 kg/ha), Medium (40 kg/ha), Long (30 kg/ha), Hybrids (20 kg/ha).
- Treatment: Carbendazim (2g/kg) or Pseudomonas fluorescens (10g/kg). Bio-fertilizers: Azospirillum + Phosphobacteria.
- Age of Seedlings: Short (18-22 days), Medium (25-30 days), Long (35-40 days).
B. Main Field Management
- Spacing: 15x10 cm (Short duration), 20x10 cm (Medium), 20x15 cm (Long).
- Planting Depth: Shallow planting (3 cm) ensures quick establishment and more tillers.
- Nutrient Management: General N:P:K recommendation is 120:40:40 kg/ha (varies by region). Zinc Sulphate (25 kg/ha) is crucial for preventing Khaira disease.
C. Weed & Water Management
- Weed Control: Pre-emergence: Butachlor 1.25 kg/ha or Pretilachlor 0.75 kg/ha on 3rd day. Hand weeding on 30-35 DAS.
- Water Requirement: 1200-1400 mm. Maintain 2.5cm to 5cm submergence.
- Critical Stages: Panicle Initiation, Booting, Heading, and Flowering.
5. System of Rice Intensification (SRI)
SRI is a methodology aimed at increasing the yield of rice produced in farming. Key components include:
| Component | Specification |
|---|---|
| Seed Rate | Very low (7-8 kg/ha). |
| Seedling Age | Young seedlings (14 days old). |
| Planting | Square planting (25 x 25 cm), Single seedling per hill. |
| Weeding | Use of Rotary/Cono weeder (incorporates weeds as green manure). |
| Irrigation | Alternate Wetting and Drying (AWD). No continuous flooding. |
| Nutrient | Leaf Colour Chart (LCC) based Nitrogen management. |
6. Advanced Topics & Special Cultivation
Transgenic Rice
- Golden Rice: Genetically modified to produce beta-carotene (Vitamin A precursor) to combat blindness.
- Bt Rice: Modified with Bacillus thuringiensis gene for resistance against stem borer.
- Herbicide Resistant: E.g., "Roundup Ready" rice tolerant to glyphosate.
Hybrid Rice
- Hybrids (e.g., CORH 1, CORH 2, ADTRH 1) offer 15-20% higher yield than pure line varieties.
- Requires specific nutrient management (higher dose: 175:60:60 NPK kg/ha).
PROFESSOR'S EXAM NOTE
Key Yield Stats:
1. Average Yield: Transplanted rice yields 4.0 - 6.0 t/ha. Straw yield approx 8.0 - 10.0 t/ha.
2. Harvest Sign: Harvest when 80% of panicles turn straw color.
3. Bio-fertilizers: Azolla and Blue Green Algae (BGA) are specific nitrogen fixers for rice ecosystems.
