Rice goes through a lot before it finally reaches your dinner plate (or bowl). This page discusses the varied rice environments where rice is grown, how rice is typically grown, and the importance of growing rice.
Access more information by clicking on the links provided for each topic. More in-depth material can be found on theRice Knowledge Bank.
Rice can be grown in a wide range of locations and climates. In particular, rice is most closely associated with South, Southeast, and East Asia, where 90% of the world's rice is produced (about 640 million tons).
It is grown in the wettest areas in the planet to the driest deserts. It is cultivated in relatively warm places to areas of considerable cold. Rice is produced at sea level on coastal plains and in areas near river deltas to the heights of the Himalayas.
Rice is grown in more than a hundred countries with a total harvested area of nearly 160 million hectares, producing more than 700 million tons every year.
There are primarily four ecosystems where rice is grown: irrigated, rainfed lowland, upland, and flood-prone. Each of these environments has its own ideal growing conditions, as well as limiting factors.
The irrigated rice environment accounts for about half of the harvested rice area and contributes 75% of global rice production. Because water is available for most part of the year, farmers can grow rice all year long. That means they can grow two (or even three) crops per year.
Worldwide, about 80 million hectares of rice are grown under irrigated areas. High-yielding areas of irrigated rice can be found in China, Egypt, Japan, Indonesia, Vietnam, the Republic of Korea, and the Senegal River Valley in Africa.
The main factors that limit the yield in such areas include poor management of production inputs, losses from weeds, pests, and diseases, inadequate land formation, levelling, and irrigation water, and inadequate drainage that may lead to a buildup of salinity and alkalinity.
Rainfed lowland rice is grown in bunded fields that are flooded with rainwater for at least part of the cropping season. Bunds are mounds or embankments made of earth designed to contain water in the field.This environment is characterized by a lack of water control, with floods and drought being potential problems. About 60 million hectares of rainfed lowlands supply about 20% of the world’s rice production. Adverse climate, poor soils, and a lack of suitable modern technologies keep farmers from being able to increase productivity.
Majority of lands in this ecosystem face different risks as compared to irrigated environments, and as such require different rice varieties and management strategies.
Upland rice is grown in Asia, Africa, and Latin America. About 14 million hectares of land is dedicated to upland rice, accounting 4% of global rice production.This rice environment can be found in low-lying valley bottoms to undulating and steep sloping lands with high runoff and lateral water movement. In many places, including Indonesia, the Philippines, Southwest China, and Brazil, upland rice may be intercropped with maize. Also, some upland rice fields are frequently bunded in areas with scarce water. Upland rice is grown under dryland conditions in mixed farming systems without irrigation and without puddling.
Although factors that limit yield in upland areas are numerous, the most severe biological constraint are weeds, followed by blast disease and brown spot.
The flood-prone ecosystem (this includes deepwater and floating rice environments) incorporates special rice varieties that are well-suited to flooded environments. These rice plants must be adapted to conditions such as deepwater, flash floods that may last longer than 10 days, salinity in low-lying coastal areas, and problems soils, such as acid-sulfate and sodic soils. Around 11 million hectares of rice lands worldwide are affected by one or more of these conditions.In these environments, rice yields are low and extremely variable because of problem soils and unpredictable combinations of drought and flood. Deepwater rice and floating rice are mainly grown on the floodplains and deltas of rivers such as Bangladesh, the Irrawaddy of Myanmar, the Mekong of Vietnam and Cambodia, the Chao Phraya of Thailand, and the Niger of West Africa. Flooding occurs in the later stages of plant growth and can last for several months.
RELATED: See an interactive map of different information on rice like distribution, land use, etc.
Rice goes through a series of processes before finally reaching your dinner table. Rice production can generally be divided into the following stages:
- Seed selection
- Land preparation
- Crop establishment
- Water management
- Nutrient management
- Pest management
- Harvesting
- Postharvest
RELATED: Visit the Rice Knowledge Bank for more in depth information on the good agricultural practices for irrigated rice and rainfed rice environments.
Seed is a living product that must be grown, harvested and processed correctly to maximize its viability and subsequent crop productivity. For the yield potential of any rice variety to be realized, good quality seed must be sown.
Good seed is pure (of the chosen variety), full and uniform in size, viable (more than 80% germination with good seedling vigor), and free of weed seeds, seed-borne diseases, pathogens, insects, or other matter.
Using good seed leads to lower seeding rates, higher crop emergence (more than 70%), reduced replanting, more uniform plant stands, and more vigorous early crop growth. Vigorous growth in early stages reduces weed problems and increases crop resistance to insect pests and diseases.
VIDEO: Seed sorting by flotation
The land to be planted is prepared to place the soil in the best physical condition for crop growth and to ensure that the soil surface is level. This is done using manual labor, with the use of animals of burden, or farm machinery.
Land preparation typically involves plowing, harrowing, and leveling the field to make it suitable for crop establishment. Draft animals, such as buffalo and oxen, 2-wheel tractors or 4-wheel tractors can all be used as power sources in land preparation. The initial soil tillage can also be performed with a rotovator instead of a plow.
The two main practices in establishing the rice plant is through direct seeding and transplanting.
In direct seeding, dry seed or pre-germinated seeds and seedlings are broadcast by hand or planted by machine. This is usually done in rainfed and deepwater ecosystems.
On the other hand, transplanting—transferring pre-germinated seedlings from seedbed to field—requires less seed but much more labor. This method also serves as a means of weed control.
Cultivated rice has a semi-aquatic ancestry. It is for this fact that rice is extremely sensitive for water shortage. To ensure sufficient water, most rice farmers aim to maintain flooded conditions in their field. This is especially true for lowland rice. Naturally, water management practices will vary depending on the environment.
Land preparation for flooded soils consumes more than a third of the total water required for growing rice in an irrigated production system. High water loss during land preparation is caused by water flowing through cracks in the soil.
Seepage and percolation flows from rice fields are major pathways of water loss. A rice field can be compared with a bath tub: The material of a bath tub is impregnable and it holds water well. However, water can run out immediately from even one hole, such as with removing the plug of a bath tub. Rice fields with only a few rat holes or leaky spots will rapidly loose water by seepage and percolation. Thorough puddling results in a good compacted plow pan that reduces percolation rates throughout the crop growing period. The efficacy of puddling in reducing percolation depends greatly on soil properties.
Ensuring that the rice plant gets the exact nutrients it needs to grow is of great importance. This is because each growth stage of the rice plant has specific nutrient needs.
Site-specific nutrient management (SSNM) provides scientific principles for optimally supplying rice with essential nutrients. It enables rice farmers to tailor nutrient management to the specific conditions of their field, and it provides a framework for nutrient best management practices for rice.
The rice plant has a wide array of ‘enemies’ in the field. These include rodents, harmful insects, viruses, etc. Each of these pests and diseases are controlled using specific strategies.
Understanding the interactions among pests, natural enemies, host plants, other organisms and the environment improves pest management decisions. Understanding the ecological factors that allow pests to adapt and thrive in a particular ecosystem will help to identify weak links in the pests' life cycle and factors that can be manipulated to manage them.
Depending on the variety, a rice crop usually reaches maturity at around 115-120 days after crop establishment. The harvesting activity includes cutting, stacking, handling, threshing, cleaning, and hauling. It is important to apply good harvesting methods to be able to maximize grain yield, and minimize grain damage and deterioration.
Harvesting can be done manually using sickles and knives, or mechanically with the use of threshers or combine harvesters. Regardless of the method, a number of guidelines should be followed to ensure that good grain quality is preserved during harvest operations and harvest losses are kept to minimum.
After harvest, the rice grain undergoes a number of processes depending on how it will be used. Such methods include, drying, storing, milling, and processing.
Drying is the process that reduces grain moisture content to a safe level for storage. Drying is the most critical operation after harvesting a rice crop. Delays in drying, incomplete drying or ineffective drying will reduce grain quality and result in losses.The purpose of any grain storage facility is to prevent grain loss from weather, moisture, rodents, birds, insects and micro-organisms.
Milling is a crucial step in post-production of rice. The basic objective of a rice milling system is to remove the husk and the bran layers, and produce an edible, white rice kernel that is sufficiently milled and free of impurities. Depending on the requirements of the customer, the rice should have a minimum of broken kernels.
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