Rice Growing Ecosystems

Classification of Rice Growing Ecosystems

• Source of water supplyRainfedIrrigated

• Land and Water management practices• Soil condition• Technological level

World’s Rice Land Classification

• Lowland riceIrrigated lowland riceRainfed lowland rice

• Upland rice• Deepwater rice• Floating rice

World’s Rice Land Classification………

• Irrigated lowland ricehave sufficient water available during the

entire growing season, with controlled shallow water depth between 5 to 10 cm

• Rainfed lowland ricemainly dependent on the duration of rainfall

and hence with an uncontrolled shallow water depth, ranging from 1 to 50 cm

World’s Rice Land Classification…....

• Upland ricebunded or unbunded rained fields with no

surface or rhizosphere water accumulation• Deepwater rice

unbunded fields with maximum sustained water depth from 0.5 m to 1m

• Floating ricemaximum water depth ranges between 1m to

6m for more than half of the growth duration

Rice Growing Ecosystem in Sri Lanka

• Rice land under major irrigation schemes-41%• Rice land under minor irrigation schemes-25%• Rainfed rice land-34%• Upland rice

Irrigated Lowland Rice System• 45% of world’s total rice land• 32% of South and Southeast Asian land• 50% of production of South and Southeast Asian rice• Method of establishment

- Transplanting - Direct seeding on puddled soil (broadcasting –pre germinated)- Drill seeding into dry land soil- Broadcast seeding into water

• Use new improved and hybrid, fertilizer and agro chemicals• Use modern technology and machinery• Early maturing rice ( 3 – 4 months )

Irrigated Lowland Rice System…….

• Sri Lanka : 66%Low Country Dry Zone

AmparaAnuradhapura

Low Country Intermediate Zone - Kurunegala

• Yield : 5 t/ha

Rainfed Lowland Rice System

• 30% of world’s total rice land• Majority of tropical Asia• Enough water has to accumulate in the field before

ploughing• Method of establishment

- Transplanting - Direct seeding on puddled soil(broadcasting –

pregerminated)- Direct seeding on dry soil

Rainfed Lowland Rice System……..

• Use new improved and hybrid, fertilizer and agro chemicals, modern technology and machinery

• Early maturing rice ( 3 – 4 months )

Rainfed Lowland Rice System……..

• Sri Lanka- 34%

-Low Country Wet Zone – Gampaha, Kaluthara-Low Country Intermediate Zone - Kurunegala-Mid Country Wet Zone – Kandy-Low Country Dry Zone (Maha) – Anuradhapura

• Yield : 3 t/ha• Vegetable based system at dry zone• Low yield at wet zone – low light intensity

mono cropping system

Upland Rice System

• Mostly by small subsistence farmers in the poorest regions of the world

• 10% of world’s total rice land• Asia – India, Bangladesh, Philippines, Thailand• Sri Lanka- Shifting cultivation of Dry Zone (Chena)

- Jaffna District• Yield - 1 t/ha• Use traditional varieties – drought tolerant

Upland Rice System………

• Less land preparation• Dry seed broadcasting• No fertilizer application• Problems –

rainfall distribution change in nutrient in soil weed composition

Deepwater Rice System• Standing water for a certain period of time is more

than 50 cm• Maximum water depth : 51-100 cm• Cultivate in Stagnant water areas, Tidal swamp areas• Thailand, India, Bangladesh, West Africa, Latin

America• Dry seeding or Transplanting• Seed broadcast on dry soil• Little fertilizer or pesticide application • Flooding at 50- 60 days after seeding

Deepwater Rice System……..

• Use long day maturing varieties (150 days- 240 days )

• Submergence tolerance• Ability to elongate if the

water level increase• Lodging tolerance• Good seedling vigor

Floating Rice System

• Standing water 1m to 6m for more than half of the growth duration

• Maximum water depth : 1- 6 m• Cultivate in floodplain areas• Thailand, India, Bangladesh, Northern Nigeria• Ungerminated seed broadcast on dry soil• Little fertilizer or pesticide application • Flooding at 4-20 weeks after seeding• Use long day maturing varieties (3 – 10 months )• Yield : 0.4 – 1.0 t/ha

Floating Rice System……

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