This document discusses agricultural water savings from the System of Rice Intensification (SRI) in Sichuan, China. It provides general information on the application and spread of SRI in China, and evaluations showing SRI can increase rice yields by 20-55% with modified transplanting methods. SRI also promotes more vigorous plant growth while requiring fewer inputs, especially 25.6% less irrigation water. The document then discusses research in Sichuan showing various SRI techniques like dry seedbed nurseries and mulching can save 30-50% of water for rice production compared to conventional methods, while maintaining or increasing yields. It concludes by discussing prospects for SRI to help address water management issues in Sichuan's
1. Agricultural Water Savings by SRI for
Future Water Management
in Sichuan, China
ZHENG JIAGUO
Sichuan Academy of Agricultural Sciences
2. CONTENT
• General information on SRI application in
China
• Water savings for rice production
• Prospects of water management
3. 1. General information on SRI
application in China
• Brief review of the spread of SRI
• Preliminary evaluations of SRI
• Improvements in SRI methods for Sichuan
• SRI extension in Sichuan
4. The spread of SRI in China
• SRI was developed in Madagascar and was synthesized
in the 1980s.
• Prof. Yuan Long-ping validated SRI methods with his
super-hybrid varieties in 2001, and hosted an
international SRI conference in Sanya, China in 2002.
• The most active institutions for SRI research have been
the China National Rice Research Institute (CNRRI) and
Sichuan Academy of Agricultural Sciences (SAAS).
• SRI has spread throughout China, with some techniques
different among provinces and some partial use.
• The concepts and methods of SRI can be used with
hybrid rice, Japonica rice, and tradition variety.
5.
6. SRI is a promising methodology to increase rice
yield and water productivity
• The average yield from hybrid rice in Sichuan
is 8.5 t/ha.
• When SRI methods were first introduced, they
could increase rice yield by 20%,
• With modification in the method of transplanting
(oblong and triangle), the increase was still higher,
almost 55% (Table 1).
• The spacing used in modified SRI is
considerably greater than in the original SRI.
8. Transplanting pattern
Yield
(t/ha)
Compared to CK
+ t/ha + %
CK 8.65 -- --
SRI – standard spacing 10.42 1.77 20.4
Triangle version of SRI 13.39 4.74 54.8
3rd
leaf 2nd
leaf Flag leaf Average
Length Width Length Width Length Width Length Width
SRI 64.25 1.57 71.32 1.87 57.67 2.17 64.41 1.87
CK 56.07 1.43 62.03 1.57 48.67 2.01 55.56 1.67
Table 1. Yield response to different planting patterns in rice
Table 2. Leaf blade size (cm) in response to application of SRI methods
9. SRI promotes more vigorous growth
• With SRI methods, rice plant
phenotypes from any given
genotype are improved .
• Leaf blades become bigger,
especially the functional
leaves (Table 2).
• Plant height and culm length
become longer.
• Leaf area index (LAI) is also
much higher compared to
control (CK).
10. Method
Rice
stage
Stem Sheath
Green
leaf
Withere
d leaf
Panicle Biomass
SRI
Full
heading
6,396.0 6,555.0 7168.6 315.45 2,361.7 24,902.4
Mature 4,108.8 3,265.6 3,390 2,667.3 13,592 25,407.3
CK
Full
heading
3,775.3 5,594.5 3,880.9 254.2 1,204.9 14,710.0
Mature 2,475 3,064.6 1,661.2 1,639.6 7,935.7 15,832.5
SRI over
CK
+/-%
Full
heading
69.41 17.17 84.71 24.07 96.00 59.09
Mature 66.01 6.56 104.06 62.67 71.28 60.47
Comparison of dry-matter accumulation
11. Lower inputs, especially water-saving
• SRI plants showed fewer insect problems and
diseases, and seed requirements were
reduced by 50-90%.
• During the rice-growing season, irrigation
water was reduced by 25.6%.
• Both WUE and IWUE were higher, by 54.2%
and 90.0%, respectively, thereby significantly
reducing water consumption.
12. Limiting factors for adoption
• The number of foundation plants is less with
SRI recommendations.
• It is hard to transplant the young seedling at
2-leaf age in multiple-cropping systems.
• Organic fertilizer materials and manpower are
in short supply.
• Some management measures such as timely
weeding and keeping the soil only moist are
considered by farmers to be too complex and
laborious.
14. ① Using tray nursery to raise seedlings
• The seedling nursery is managed under upland
(unflooded) conditions, with plastic trays.
• Seedlings are removed carefully from the
nursery and are transported quickly and
placed gently into paddy field within 15-30
minutes.
• This avoids a long recovery time ( there is little
transplant shock); leaf age can be extended
this way to 5.5.
18. 7
8
9
10
11
12
13
14
CK SRI S+3 S+T O+T
Tr anspl ant i ng pat t er n
Yield(T/ha)
Transplanting pattern and yield results
S+3 = Square with 3 seedlings; S+T= Square with triangle;
O+T = Oblong with triangle
19. 7
8
9
10
11
12
13
14
40× 40 40× 45 45× 45 45× 50 50× 50 55× 55
Space ( cm)
Yield(t/ha)
Relation between yield and transplanting density with
triangular transplanting configuration
21. ④ Application of herbicides for
weed control – so far, no soil-
aerating weeding is being used
with SRI in Sichuan
⑤ Adding chemical fertilizers
when needed is usual practice
23. ⑦ Shallow furrows in field for drainage
• This is appropriate for the alternate wetting
and drying (AWD) method, an effective and
easy method for SRI water management.
• Shallow furrows help to implement AWD,
maintaining aerated soil surfaces while some
water remains in the furrows and moves
laterally to moisten the root zone.
25. The modified SRI
Seedling
nursery
Transplant management
Increase organic
fertilizer and
balance the
nutrients
Alternate wetting
and drying and
mid-season
drainage
Upland nursery
with plastic tray
Transplant in early
season
Shallow transplant
with low density
Oblong and triangle
pattern
26. SRI extension in Sichuan
• Extension has been guided by the Provincial
Agricultural Extension Bureau.
• By 2010, the SRI area in Sichuan had reached
>300,000 ha, starting from 1,133 ha in 2004.
• The average SRI yield has been 9.5 t/ha,
representing an average increase of 1.8 t/ha
over the province average paddy yield.
27. Year 2004 2005 2006** 2007 2008 2009 2010
SRI area (ha) 1,133 7,267 57,400 117,267 204,467 252,467 301,067
SRI yield (kg/ha) 9,105 9,435 8,805 9,075 9,300 9,495 9,555
Conv. yield (kg/ha) 7,740 7,650 7,005 7,395 7,575 7,710 7,740
SRI increment (t/ha)* 1,365 1,785 1,800 1,680 1,725 1,785 1,815
SRI % increase in yield* 17.64 23.33 25.7 22.72 22.77 23.15 23.45
Grain increment (tons) 1,547 12,971 103,320 197,008 352,705 450,653 546,436
Input increment by SRI
(RMB Yuan/ha)
834 969 736.5 771 900 1,020 1,200
Grain price (RMB Yuan/kg) 1.44 1.44 1.44 1.5 1.8 1.84 1.95
Additional net income
attributable to SRI in Sichuan
(million RMB Yuan)*
1.28 11.64 106.51 205.10 450.85 571.69 704.27
Table 4. Extension of SRI in Sichuan province
28. Year Area under
SRI mgmt
(ha)
No. of farmers
using SRI
Average SRI
yield (t/ha)
Aver.
conv.
yield
(t/ha)
2013 385,000 1,283,000 9,302 7,900
2012 383,533 1,278,000 9,280 7,850
2011 365,667 1,218,500 6,450 7,780
2010* 301,067 1,003,000 9,555 7,740
SRI area and number of farmers in recent years
* Drought year: SRI yields were relatively better than with conventional methods
29. 2. Water savings for rice
production
• General information about Sichuan province
• Water-using characteristics in rice cultivation
• Individual research on water-saving for SRI
• Impact of water-saving techniques and
demonstrations in Sichuan
31. Sichuan is located in southwest China
• The rainfall in province is 1,000 mm annually.
• Water resources are about 3,040 m3
per capita, which is
higher than China's average.
• The hilly regions have the most serious water shortage. The
water resources per capita there are 940 m3
-- just 31% of the
province average, and less than 40% of the national average
of 2,477 m3
.
• Agriculture consumes 80% of the total water resources in
Sichuan.
• Water use efficiency (WUE) of staple crops such as rice,
maize, and wheat is about 0.9 kg/m3
.
32. ① Irrigation systems well developed on Chengdu Plain
• Chengdu Plain covers 10,000 km2
.
• Dujiangyan Irrigation System, built over 2,000 years ago,
enables irrigation automatically.
• The thermal conditions provide adequate temperature for
the rice-wheat cropping system.
• But WUE is lower because of flood irrigation or cascade
(field-to-field) irrigation.
Dujiangyan
Irrigated area: 670, 000 ha
in 1998
33. ② Seasonal droughts are the main restricting
factor in hilly areas
• Seasonal droughts are quite frequent, due to the
uneven distribution of rainfall during rice growth.
• Drought disasters, such as withered rice seedlings or
waiting for rainfall to transplant, occur every year.
Withering Yellow leaf
34. Lack of
water
Lack of
water
DelayDelay YellowwitheringYellowwithering Low seed setLow seed set
Sow Transpl. Elongation Heading Mature
Nursery Tiller Panicle initiation Filling and ripen
SpringSpring Summer Hot summer
The influence on rice from seasonal
drought in Sichuan hilly region
Drought
35. ③ Groundwater resources are seldom
used directly
• Agriculture relies mostly on surface water.
• Rice depends on permanent paddy field water
storage in the hilly region, because there are no
reservoirs or irrigation projects.
36. Research on rice water-saving
Landscape and the experiment plots
37. ① Dry seedbed nursery
• The seedbed is established under upland
conditions and kept dry during the nursery
period, with just hand watering if needed.
• Because rainfall can be used directly in
upland seedbeds, more than 50% of the
irrigation water is saved during the nursery
stage (about 45d, ≥7 leaf age). Also, seedling
quality is much better than with a wet
(flooded) seedbed nursery.
38. Rain-
fall
(m3
/ha)
Irrigation
water
(m3
/ha)
Total
consumption
(m3
/ha)
Comparison to CK
(±)
(m3
) (%)
DS 315 95.1 410.1 484.1 54.14
WS (CK) 315 579.2 894.2 -32.27 -
Emer-
gence
(%)
Seed-
ling
(%)
Height
(cm)
Dry
matter
(g/seed-
ling)
Dry wt/
fresh
(%)
No. of
tillers
(/seedling)
Recove
ry time
(days)
D
S
92.6 89.2 29.98 0.63 24.42 4.36 0.5
C
K
82.7 79.2 39.49 0.57 17.17 2.94 7.5
Table 5. Water consumption for rice nursery
Table 6. Seedling quality differences between nursery methods
DS: Dry seedbed; WS: Wet seedbed
40. ② Mulching in rice cultivation
• Mulching by crop residues conserves soil moisture and
suppresses weeds.
• Small farmers have the labor to manage the mulching.
• It can save 30% of water, and increase yield by 6%; WUE is
increased by 0.52 kg/m3
, and IWUE increases by 1.24 kg/m3
.
• Mulching with plastic film saves more water and reduces
losses to drought. But plastic pollution can become a serious
problem.
44. ③ Irrigation methods
• AI: aerobic irrigation, as recommended for SRI
• AWD: alternative wetting and drying
• SWD: shallowwetdry sequential management
46. Fertil-
izer
Irrigation water
(m3
ha-1
)
Available rainfall
(m3
ha-1
)
WUE
(kg m-3
)
IWUE
(kg m-3
)
AI CF AI CF AI CF AI CF
F25 4,726.5 7,606.5 5,110.5 5,110.5 0.7814 0.5470 1.6236 0.9145
F50 4,726.5 7,606.5 5,110.5 5,110.5 0.8228 0.5720 1.7125 0.9562
F100 4,726.5 7,606.5 5,110.5 5,110.5 0.7900 0.5520 1.6442 0.9228
Mean 0.7981 0.5570 1.6601 0.9312
Table 10 Effect of organic matter treatments and irrigation method on water productivity (paddy produced per m3
water)
F25 = 25% organic, F50 = 50% organic, F100 = 100% organic, AI = aerobic irrigation, CF = continuous flooding
F25 = 25% organic, F50 = 50% organic, F100 = 100% organic
AI = aerobic irrigation, CF = continuous flooding
Effect of organic matter treatments and irrigation method
on water productivity (paddy produced per m3
water)
47. Impact of water-saving techniques
• The technical approach includes:
– Tillage, nursery method, water and fertilizer
management.
• Significant quantities of water have been saved.
• Traditional water consumption in paddy fields was
9,795.2 m3
/ha, with 8,279.85 m3
/ha of this being
irrigation water.
• Water productivity was 0.82 kg/m3
, and the
irrigation water use efficiency was 0.97 kg/m3
.
49. 3. Prospects of water management
• Rice and water management
• Future trends in crop cultivation
• Key research subjects for water saving in
rice cultivation
50. Rice and water management
• Rice is the world’s most important food crop and a
major staple food.
– China’s 31.7 million ha of rice fields -- which
account for 20% of the world’s rice area --
produce about 35% of total rice grain.
• Rice consumes large quantities of irrigation water,
up to about 90% of the total water for all crops.
• However, fresh water for irrigation is becoming
scarce because of increasing competition from
urban, industrial, and environmental factors.
51. • Water limitations threaten the sustainability of
irrigated rice systems in many countries.
• Rice offers great potential for saving irrigation
water because its physiological water
requirement (4,500 m3
water/ha) is much less
than what is currently (incorrectly) considered
to be needed and than what is currently
applied.
• Water-saving rice-cultivation methods are
urgently needed to keep up with future food
demands, while at the same time they are
important for ensuring the future viability of
rice production systems.
52. Future trends in crop cultivation
• To promote sustainable development in agriculture,
China must simplify the cultivation process, reduce
the water requirement, and lighten the workload.
• Direct sowing of rice and ratooning will be popular,
but some agronomic questions must be answered.
• Agricultural machinery must be introduced into all
crops cultivation.
• SRI is not a fixed technology, but rather a set of
ideas for creating a more beneficial growing
environment for rice.
– We expect further modifications and improvements
55. Organic & chemical component fertilizer
Delayed (controlled) release fertilizer :
decrease amount of N in tillering stage; increase
the N in panicle initiation (PI) and grain-filling
stages.
Labor saving: fertilizer application is 1 time only
Nitrogen saving : N utilization efficiency is
increased by 5.7-25.9% in SRI.
Yield : + 9.9 ~ 10.8 % compare to tradition
method.
57. Key research subjects for water
saving in rice cultivation
• Water balance in paddy fields and water
requirements in different ecosystems.
– The growing of rice should be based on scientific
knowledge and consider following factors: regional
ecological conditions, cropping systems, natural
rainfall, available irrigation resources, and so on.
• Varieties for drought-tolerance and screening
methods.
– There is considerable difference among varieties for
their drought-tolerance. Some can be suitable in arid
areas or areas with more uncertain water availability.
58. • Sensitive growth stages for water stress and
their influence.
– Limited water resources to be allocated for use
during rice’s most sensitive growth stages. Natural
rainfall needs to be used as efficiently as possible, and
the water demands for rice growing should be
reduced as much as possible.
• Engineering approach for saving water.
– Increased water conservation projects in hilly regions
should be pursued, along with reductions in water
losses in irrigation channel systems; appropriate use
of groundwater systematic development.