Agricultural Water Savings by SRI for Future Water Management

in Sichuan, China

ZHENG JIAGUOSichuan Academy of Agricultural Sciences

CONTENT

• General information on SRI application in China

• Water savings for rice production• Prospects of water management

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

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.

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.

3 seedlingsseparated

3 seedlings in 1 hill

Transplanting pattern Yield(t/ha)

Compared to CK

+ t/ha + %

CK 8.65 -- --SRI – standard spacing 10.42 1.77 20.4Triangle version of SRI 13.39 4.74 54.8

3rd leaf 2nd leaf Flag leaf AverageLength 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

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).

MethodRice stage

Stem SheathGreen

leafWithered 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

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.

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.

Improved SRI methods for Sichuan

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.

30cm

15cm

Farmers’ usual practice

Leaf-age 7 Oblong >6 seedlings

40cm

35cm

7cm

② Modified SRI: oblong with triangle

7

8

9

10

11

12

13

14

CK SRI S+3 S+T O+T

Transpl anti ng pattern

Yie

ld(T

/ha)

Transplanting pattern and yield results

S+3 = Square with 3 seedlings; S+T= Square with triangle;

O+T = Oblong with triangle

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

752.6 737.2 724.5 696.1

576.5

500

550

600

650

700

750

800

850

公斤

/亩

3叶/5000 4叶/6000 5叶/7000 6叶/8000 7叶/13636

叶龄与密度的组合

移栽叶龄与密度组合的稻谷产量（2005，新都）

③ Younger seedlings are better

Leaf age / density (plants/667m2)

Yield Kg/667m

2

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

⑥ Midseason drainage is done for inhibiting unproductive tillering

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.

Shallow furrows in paddy field

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

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.

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

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

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

The R-W cropping system distribution in China

Sichuan

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.

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

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.

WitheringWithering Yellow leafYellow leaf

Lack of water

Lack of water

DelayDelay Yellow\witheringYellow\withering 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

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.

Research on rice water-saving

Landscape and the experiment plots

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.

Rain-fall

(m3/ha) Irrigation water (m3/ha)

Total consumption

(m3/ha)

Comparison to CK (±)

(m3) (%)DS 315 95.1 410.1 484.1 54.14WS (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)

Recovery time(days)

DS

92.6 89.2 29.98 0.63 24.42 4.36 0.5

CK 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

Dry seedbed nursery

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.

Mulching with wheat straw

Caution: Plastic pollution

can be a problem

Yield(kg·hm-2)

Irriga-tion

(m3·hm-2)

TWC(m3·hm-2)

WUE(kg·m-3

To CK±

(kg·m-3)

IWUE(kg·m-3)

To CK±

(kg·m-3)

MBR9,467.10 3,506.55 6,091.65

1.55 0.52 2.70 1.24

CK8,941.65 6,121.80 8,706.90

1.03 - 1.46

Table 8. Comparison of water efficiency under different models

MBR: mulching of wheat straw into broad rows; CK: farmers’ practice. TWC: total water consumption; WUE: water using efficiency; IWUE: irrigation water using efficiency.

③ Irrigation methods

• AI: aerobic irrigation, as recommended for SRI

• AWD: alternative wetting and drying

• SWD: shallow\wet\dry sequential management

Treatment Panicles(m-2)

1000- grain weight (g)

Grains panicle-1

Filled grains (%)

Yield(kg ha-1)

Harvest Index (HI)

F25/AI 223.7b 29.2 170.5 71.4 7,686.6b 0.4538

F25/CF 230.2ab 29.1 160 69.3 6,956.0d 0.427

F50/AI 230.0ab 29 173.9 70.5 8,094.2a 0.4767

F50/CF 237.5a 28.7 162.1 70.6 7,273.7c 0.5083

F100/AI 232.7ab 29.8 175.6 64.1 7,771.3b 0.4251

F100/CF 231.3ab 28.4 161.1 69.4 7,019.6d 0.4293

AI 228.8 29.3 173.3 68.7 7,850.7 0.4519

CF 233.0 28.7 161.1 69.8 7,083.1 0.4549

Effects of irrigation methods and organic fertilization on grain yield and yield components

AI = aerobic irrigation; CF = continuous flooding; F25 = 25% organic fertilization, 75% chemical fertilization; F50 = 50% organic fertilization; F100 = 100% organic fertilization

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)

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.

leakage

稻田

Evaporation

Irrigation Drainage

RainfallRainfall

Water requirement for

paddy rice

1717.8 m32.07mm/d

6364.4 m3

1.89 mm/d

Spilled

Save water: 2193m3/ha (22.04%)

WUE= 1.12 kg/m3

+0.30 kg/m3

IWUE=1.34 kg/m3

+0.37 kg/m3

Water balance in paddy field and water requirement (with modified SRI)

202.5 m3

3. Prospects of water management

• Rice and water management • Future trends in crop cultivation• Key research subjects for water saving in

rice cultivation

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.

• 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.

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

技术特点：可同步开沟、起垄和播种，集成轻简直播、好气强根、节水节肥技术特点：可同步开沟、起垄和播种，集成轻简直播、好气强根、节水节肥等多项农艺措施。等多项农艺措施。

11 ）垄沟作灌溉水沟，保证水稻生长所需；稻种播在垄面上小沟中，湿润促全苗。）垄沟作灌溉水沟，保证水稻生长所需；稻种播在垄面上小沟中，湿润促全苗。22 ）垄沟有水、垄面无水，湿润节水，好气强根。）垄沟有水、垄面无水，湿润节水，好气强根。33 ）垄面上的播种小沟增加了水稻根系的入土深度，较好地解决了一般直播稻播在泥面）垄面上的播种小沟增加了水稻根系的入土深度，较好地解决了一般直播稻播在泥面上而根系入土较浅、容易倒伏的问题。上而根系入土较浅、容易倒伏的问题。

SRI + SRI + Mechanization?Mechanization? + Direct + Direct SeedingSeeding ??

分蘖期分蘖期

成熟期成熟期

移栽期移栽期

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.

Ratooning rice for hybrid rice

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.

• 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.

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