1. Introduction
Rice (Oryza sativa L.) is among the most important staple food crops globally, serving as the primary dietary component for more than half of the world's population. It belongs to the Poaceae family and is primarily cultivated in tropical and subtropical regions due to its preference for warm and humid conditions. Rice farming supports millions of livelihoods and plays a vital role in food security, particularly in Asia.
2. Origin and Distribution
Rice is believed to have been domesticated in the Yangtze River Valley in China around 10,000 years ago. Since then, its cultivation has spread across various continents. Today, rice is cultivated in Asia, Africa, Latin America, and parts of Europe and North America. The largest rice-producing countries include China, India, Indonesia, Bangladesh, Vietnam, and Thailand, with Asia accounting for over 90% of global rice production.
3. Climate Requirements
Rice is a warm-season crop that thrives in specific climatic conditions:
- Temperature: Optimal range is 20°C to 35°C
- Rainfall: 1000-2000 mm annually or irrigation-supported
- Sunshine: Minimum 5 hours of sunlight per day
- Humidity: High humidity during vegetative and reproductive stages is favorable
4. Soil Requirements
Rice can grow in a wide range of soil types with the following characteristics:
- Alluvial, clay loam, and sandy loam soils
- Soil pH between 5.5 and 7.0 (acidic to neutral)
- Good water-holding capacity and low permeability, particularly for lowland rice fields
5. Varieties of Rice
Rice varieties are classified based on their adaptation to different environments:
- Lowland: Transplanted and direct-seeded types
- Upland: Suitable for rainfed, non-puddled fields
- Basmati: Aromatic, long-grained rice
- Popular Varieties: IR-64, Swarna, MTU-1010, Pusa Basmati-1, Naveen, Sahbhagi Dhan (drought-tolerant)
6. Land Preparation
- Multiple ploughings (2-3 times) for fine tilth
- Puddling in lowland fields to reduce water percolation and improve transplanting conditions
- Incorporation of organic manure (FYM/compost) during final ploughing
7. Sowing and Planting Methods
There are two main methods of rice planting:
- Transplanting: Seedlings (21-30 days old) raised in nurseries and planted in puddled fields with 20 x 15 cm spacing
- Direct Seeding: Seeds sown directly in dry or wet fields using broadcasting or drilling
Types of Sowing Methods:
- Dry Direct Seeding (DDSR): Sown into dry soil, requires less water and labor
- Wet Direct Seeding (WDSR): Sown into wet, puddled fields for better weed control
- Broadcasting: Scattering seeds uniformly, less uniform plant population
- Drilling: Sowing in rows with seed drills for proper spacing
- Dibbling: Placing seeds manually into holes, rarely used for rice
- Transplanting: Traditional and widely adopted method for higher yield
- System of Rice Intensification (SRI): Younger seedlings, wider spacing, intermittent irrigation for improved productivity
8. Seed Rate and Treatment
- Transplanting: 30–35 kg/ha
- Direct seeding: 80–100 kg/ha
- Treatment: Fungicide treatment (Carbendazim/Thiram), and biofertilizers (Azospirillum, PSB)
9. Water Management
- Maintain 5–10 cm water depth during active crop stages
- Drain fields before harvest for easier operations and improved grain quality
10. Nutrient Management
Recommended fertilizer application per hectare:
- Nitrogen: 100–120 kg
- Phosphorus: 40–60 kg
- Potassium: 40–60 kg
- Split nitrogen application during basal, tillering, and panicle initiation stages
- Incorporation of FYM, green manure, and biofertilizers enhances soil health
11. Weed Management
- Manual weeding: Twice (20 and 40 days after transplanting)
- Herbicides: Pre-emergence (Butachlor, Pendimethalin), Post-emergence (2,4-D, Bispyribac-sodium)
12. Pest and Disease Management
Major Pests:
- Stem borer
- Brown planthopper
- Leaf folder
- Gall midge
Major Diseases:
- Blast
- Bacterial leaf blight
- Sheath blight
- False smut
Use of Integrated Pest Management (IPM) strategies, including resistant varieties, biological control, and judicious chemical application, is recommended.
13. Harvesting and Yield
- Harvesting is done when grains are mature and hard (25–30% moisture)
- Methods: Manual harvesting, mechanical harvesters
- Yield: 2.5–6.5 tonnes/ha depending on practices, variety, and ecosystem
14. Post-Harvest Operations
- Threshing
- Drying grains to 12–14% moisture
- Cleaning, grading, and storage
- Milling: Removal of husk and polishing
15. Conclusion
Rice cultivation continues to be vital for ensuring food security and supporting rural economies in many parts of the world. Embracing modern technologies, improved varieties, sustainable practices, and integrated management approaches can significantly boost rice productivity, profitability, and environmental resilience.
