Principle of System of Rice Intensification (SRI)

SRI Paddy Cultivation requires less water and less expenditure gives more yields, Beneficial for small and marginal farmers.

SRI Technology Uses - Less External Inputs

In SRI Paddy Cultivation Less Seed (2kg/ac) is required and fewer plants per unit area (25x25cm) whre as in general Paddy Cultivation 20kg seed is required per acre.

SRI requires less expenditure on fertilizers and plant protection chemicals.

Root Growth

In SRI System Rice Crop grows healthy in natural conditions and its root growth can be massive receives nutrients from deeper layers of the soil. 3 hills under conventional method required 28kg of force to be pulled up where as single SRI rice plants required 53 kg for uprooting.

SRI is initially labour intensive

• Needs 50% more man days for transplanting and weeding.
• Mobilises labour to work for profit.
• It offers an alternative to resource poor, who puts in their family labour.
• Once skills are learnt and implements are used, the labour costs will be lesser than the present day rice cultivation.

SRI encourages rice plant to grow healthy with

• Large root volume
• Profuse and strong tillers
• Non lodging
• Big panicle
• More and well filled spikelets and higher grain weight
• Resists insects because it allows rice to grow naturally

Tillering is greatly increased

• 30 tillers per plant are fairly easy to achieve
• 50 tillers pen plant are quite attainable.
• With really good use of SRI, individual plants can have 100 fertile tillers or even more.

Because no set back due to early transplanting and no die back of roots.

Maximum tillering occurs concurrently with panicle initiation. More filled grain per panicle and no lodging of crop.

• Everybody believe that Rice is an aquatic plant and grows best in standing water.
• Rice is not an acquatic plant, it can survive in water but does not thrive under hypoxic conditions.
• Rice plants spends lot of its energy to develop air pockets (aerenchyma tissue) in its roots under continous inundation.
• 70% of Rice root tips get degenerated by flowering period.
• Under SRI Paddy fields are not flooded but keep the soil moist during vegetative phase later only one inch water depth is sufficient.
• SRI requires only about half as much water as normally applied in irrigated rice.

Six Mechanisms and Processes for SRI

1. Early Transplanting Seedling 8-12 days old, when plant has only two small leaves, before fourth phyllochron.	More tillering potential More root growth potential
2. Careful Transplanting Minimize trauma in transplanting. Remove plant from nursery with the seed, soil and roots carefully and place it in the field without plunging too deep into soil.	More tillering potential
3. Wide Spacing plant single seedlings, not in clumps, and in a square pattern, not rows, 25cm x 25cm or wider	More root growth potential
4. Weedling and Aeration needed because no standing water, use simple mechanical "rotating hoe" that churns up soil; 2 weedings required, with 4 recommended before panicle initiation; first weeding 10 days after transplanting.	More root growth, due to reduced weed competition, and aeration of soil, giving roots more oxygen and N due to increased microbial activity we left in soil; can add 1+tons per weeding? Each additional weeding after two rounds results in increased productivity up to 2 t/ha / weeding.
5. Water Management regular water applications to keep soil moist but not saturated, with intermittent dryings, alternating aerobic and anaerobic soil conditions.	More root growth because avoids root degeneration able to acquire more and more varied nutrients from the soil
6. Compost / FYM applied instead of or in addition to chemical fertilizer; 10 tons/ha;	More Plant growth because of better soil health and structure, and more balanced nutrient supply.

In SRI Cultivation 8 to 12 days old seedlings are planted. So root system grows well and gives 30 to 50 tillers. When all the 6 management practices are followed then per plant 50 to 100 tillers are produced and high yields can be realised.

Nursery Management

• Seed rate 2 kg/ac
• Nursery area 1 cent / ac
• Select healthy seed
• Pre-sprouted seeds are sown on raised nursery bed
• Prepare nursery bed like garden crops
• Apply a layer of fine manure
• Spread sprouted seed sparcely
• Cover with another layer of manure
• Mulch with paddy straw
• Water carefully
• Banana leaf sheath may be used for easy lifting and transport of seedlings.

Main field preparation

Land preparation is not different from regular irrigated rice cultivation. Levelling should be done carefully so that water can be applied very evenly. At every 3m distance form a canal to facilitate drainage. With the help of a marker draw lines both way at 25x25cm apart and transplant at the intersection.

Benefits of SRI

Higher yields - Both grain and straw Reduced duration (by 10 days) Lesser chemical inputs Less water requirement Less chaffy grain % Grain weight increased without change in grain size

• Higher head rice recovery
• Withstood cyclonic gales
• Cold tolerance
• Soil health improves through biological activity

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