1. Prepared By:
Suraj Poudel*
Puspa Poudel**
*Institute of Agriculture and Animal Science, TU
**College of Natural Resource Management, AFU
2. Introduction:
Rice is the most important staple food crop grown in Nepal.
Production of rice in Nepal is increasing because of high yielding
varieties.
These high yielding varieties tend to be highly responsive to key
inputs such as fertilizers, pesticides, and notably irrigation water.
But water resources are depleting faster because of climate change.
3. Introduction Contd.
Ground water is being exploited for crops production at
unsustainable levels.
These challenges call for a new technologies which help to increase
Water Use Efficiency.
The SRI (System of Rice Intensification) offers a valuable option in
this context.
4. Definition of SRI:
SRI is a methodology for increasing the productivity of irrigated rice
cultivation while at the same time reducing inputs, including seeds,
fertilizers and water requirements.
This counter intuitive effect is achieved by improved management of
plants, soil, water and nutrients, which stimulates biological
processes that have a positive effect on plant growth and tiller
production.
SRI should not be understood as a fixed package of technical
specifications, but as a system of production that is still evolving.
5. Evolution and spread of SRI:
SRI was developed in Madagascar in the
early 1980s by Fr. Henri De Laulanie,
a French priest.
He came to Madagascar from France in 1961
and spent the next 34 years of his life working
with Malagasy farmers to improve their agricultural
systems, particularly their rice production.
His keen observations and continuous experimentation led to SRI.
The spread of SRI from Madagascar has been credited to Norman
Uphoff.
Photo: Henri De Laulanie
6. Evolution and spread of SRI Contd..
Norman Uphoff was former director of the Cornell Institute for
Food, Agriculture and Development at Cornell from 1990 to 2005.
In 1997, he started to promote SRI in Asia.
In Nepal, SRI was started by Rajendra Uprety when he was District
Agriculture Extension Officer in Morang.
Till now, SRI is practiced in thirty-five districts across the country.
7. Benefits of SRI:
Increase in yield/ha (21 to 105%).
Increase in net income/ha (59 – 412% ).
Reduction in cost of production (7 – 56%).
Reduction in water requirement (24 – 60%).
Shorter time to maturity (1-3 weeks less).
Protection against biotic stresses pests/diseases (Sheath blight, leaf
folder, brown plant hopper) 70% reduction in incidence.
8. Benefits of SRI Contd.
Tolerant to abiotic stresses like drought, storm damage, extreme
temperatures.
Higher milling outturn (by ~ 15%) as there are fewer unfilled grains
(less chaff) and fewer broken grains (because they resist shattering).
Little or no chemical residues on grain because of less or no any
agrochemicals used.
Decrease in methane emission due to mid season drainage and
intermittent irrigation by 40%.
9. SRI Principles:
SRI is based on six principles:
seedlings get transplanted at a much younger age at 8-12 days old (2 leaf
stage) ;
only single seedling, instead of a handful of seedlings get planted in each
hole;
increased use of organic fertilizer to enhance soil fertility;
intermittent water application to increase wet and dry soil conditions, instead
of continuous flood irrigation;
plants are spaced wider apart; plants were set out carefully and gently in a
square pattern, 25x25cm or wider if the soil is very good and
Conoweeder/ rotary hoe/power weeder to control weeds and promote soil
aeration.
10. SRI Methods:
1. Raising nursery
(a) Selection of site :
The nursery bed should be preferably prepared in the center / corner
of the plot for quick / efficient transplanting.
(b) Size of bed:
For one acre transplantation, the nursery bed can be raised in 48
square yard (40 sq. meter) plot.
Depending upon the situation, two beds can be raised each measuring
24 sq. yards (20 sq. meters) per 1 kg seed.
11. SRI Methods Contd..
( c ) Bed preparation:
Nursery bed is prepared with application of farm yard manures (FYM) and
soil in four alternating layers.
1st layer: 1 inch (2.54 cm) thick well decomposed FYM,
2nd layer: 1 .5 inch (3.75 cm) soil.
3rd layer :1 inch (2.54 cm) thick well decomposed FYM,
4th layer: 2.5 inch (6.3 cm) soil.
All these layers should be mixed well as it will helps in easy penetration of
roots.
Besides compost, vermicompost can also be used and spread it over all the bed
in 3-5 cm layer.
13. SRI Methods Contd..
(d) Seed rate:
2 kg of seeds (5 kg / ha) is required to transplant in one acre of land.
Seed should be thinly spread to avoid crowding of seedlings.
(e) Seed Treatment :
Healthy and pure seeds are soaked for 12 hours in water.
Drain the water and treat the seed with bavistin (2 g/kg seed) or
Trichoderma (3 g/kg seed).
Transfer the treated seeds to a water soaked gunny bag and leave it
for 24 hours.
Sprouted seeds are taken to the nursery for sowing and broadcasted.
It is better to broadcast seeds in the evening.
14. SRI Methods Contd ..
(f) Mulching :
It is done to protect from direct exposure to the sun and also to ensure
protection from birds.
It can be done with paddy straw.
Remove the straw once seeds germinate.
2. Land Preparation:
Land selected should be well leveled with drainage facility.
When the plot is irrigated the water should spread uniformly across the
field.
The main field is prepared and leveled with little standing water a day
before planting for grid marking.
Provision should be made for 30 cm wide channels at 2 meters
interval.
15. SRI Methods Contd ..
3. Method of transplanting:
Care should be taken to prevent any harm to seedlings while pulling
them from nursery or at the time of transplanting.
A metal sheet is inserted 4-5 inches below the seedbed and seedlings
scooped along with soil without any disturbance to their roots.
Seedling must be transplanted singly with their roots intact.
They must not be plunged too deep, but placed at a depth of 1- 2 cm
from the surface.
Seedlings are transplanted with the help of index finger and thumb and
by gently placing them at the intersection of marking.
Light irrigation should be given on the next day of the transplanting.
18. SRI Methods Contd ..
4. Nutrient Management:
Organic manures / vermicompost are recommended in SRI
cultivation as they give better response and improve soil health.
Application of FYM / compost (10-12 t/ha) before ploughing and
incorporation of in situ grown 45-60 days old green manures crops
are beneficial.
Though complete organic manuring is recommended for SRI, in
case of short supply of organics, fertilizer supplementation may be
adopted for better yields.
19. SRI Methods Contd ..
5. Water management :
SRI method does not require continuous flooding.
Irrigation is given to maintain soil moisture near saturation initially
and water is let in when surface soil develops hairline cracks..
As a result, the roots of the paddy plants grow healthy, extensively in
all directions.
As the field is intermittently irrigated and dried, the micro organisms
grow well which make nutrients available to the plants.
The field should be irrigated again when the soil develops hair line
cracks.
20. 5. Water management :
At the time of weeding operation to avoid
shoulder pain, the field should be irrigated
to have 2-3 cm of water.
After completion of weeding the water
should not be let out of the field.
After the panicle initiation stage until maturity, one inch of water
should be maintained in the field until maturity.
The water can be drained after 70% of the grains in the panicle get
hardened.
Photo: Drying of field
21. SRI Methods Contd ..
6. Weed Management:
Alternate wetting and drying in SRI results in excessive weed
growth.
Weeding is done by cono weeder between rows at the right time,
which also supply nutrients to the crop as green manures.
First weeding is to be done 10-12 days after planting and at 10-15
days interval afterwards.
For smoother and easy operation of cono weeder, it is advisable to
coincide weeding with irrigation.
This results in profuse growth of diverse soil micro organisms which
make nutrients available to the plant.
22.
23. Reasons of high yield under SRI:
Increase in rice yield and reduction in input of water, seeds, chemical
nutrient and fertilizer have been reported under SRI.
This superior performance results from biological processes that are
stimulated by SRI practices that are beneficial for the development
of plants and the production of grains.
The transplantation of very young seedlings contributes to an
improved development of root system, which ultimately leads to a
better nutrient supply to the plant.
Rice plants grown in aerated soil develop larger root system than
under flooded conditions.
Moreover, aerated soil harbors beneficial soil microorganisms.
24. Reasons of high yield under SRI Contd..
The wider spacing allows for sunlight to get through to the plants
lower leaves and results in a higher level of photosynthetic activity.
Balanced and complete nutrients is achieved in SRI through organic
materials like compost, mulch, etc.
This also increases plants resistivity to pests and diseases.
Tillers are strong and profuse due to extensive root system and
better nutrient supply.
These tillers produces big panicles and well- filled spikelet with
higher grain weight.
25. Comparison of SRI against Conventional method:
Parameters SRI Conventional method
Seed Rate 5 kg/ ha 50- 60 kg/ha
Transplanting of
seedling
After 8- 12 days After 25- 35 days
No. of seed per hill one Three or more
Fertilization Preferred application of
organic fertilizer
Application of chemical
fertilizers
Weed management Frequent weeding by
conoweeder
Use water to control
weeds, herbicides etc
Water management Alternate wetting and
drying
Continuous flooding
WWF/ICRISAT (2007)
28. References:
V&A Programme (2009). Vulnerability and Adaptation experiences
from Rajasthan and Andra Pradesh: The System of Rice
Intensification SDC V&A Programme, India.
Uphoff N. (2006). The system of rice intensification (SRI) as a
methodology for reducing water requirements in irrigated rice
production. International Dialogue on Rice and Water: Exploring
Options for Food Security and Sustainable Environments. IRRI, Los
Baños, Philippines.
