Evaluation of the System of Rice Intensification in Bhutan

Karma Lhendup

Faculty of AgricultureCollege of Natural Resources

Royal University of BhutanThimphu

2nd National SRI Symposium, 2007

Brief background on paddy cultivation in Bhutan

Rice is cultivated in a wide range of elevations from 150 m - 2600 masl

Over 50,000 acres -- about 20,235 hectares -- are under rice cultivation in Bhutan (MoA, 2004)

Average rice productivity is about 2.88 ton/ha

SRI in Bhutan

No documentation of any SRI activities in Bhutan prior to 2006

In 2006, SRI evaluation trials were carried out at three locations in Eastern Bhutan.

ObjectiveTo assess the respective responses to SRI practices of different rice varieties (cultivars) popularly grown in Bhutan.

To disseminate and promote SRI technique to community and agriculture extension workers.

To seek greater knowledge about SRI under Bhutanese conditions

BumthangLhuentse

Thimphu

Haa

Paro

Mongar

Zhemgang

Samtse SarpangDagana

Trashigang

Chhukha

Punakha

Wangdi-Phodrang

Samdrup-Jongkhar

Trongsa

Trashi-Yangtse

Pema-Gatshel

Gasa

Tsirang

S

N

EW

Site I (Khangma)

Site II (Thragom)

Site III (Pangthang)

Kanglung Geog Kanglung is one of the

16 Geogs (blocks) of

Trashigang district

Methodology: Location of study sites

Site Characteristics

Site

Altitude (masl) Texture

Variety planted

pH (H2O)

I (Khangma) 2000 LoamKhangma maap 4.4

II (Thragom) 1850 Loamy to sandy clay Paropa 4.47

III (Pangthang) 1600Sandy loam to sandy clay loam Verna 5.99

Site I Site II Site III

Experimental Design

RCBD with 3 replications and 5 treatments

Treatments were:20 x 20 cm spacing, 3-leaf stage seedling age20 x 20 cm spacing, 4-leaf stage seedling age30 x 30 cm spacing, 3-leaf stage seedling age30 x 30 cm spacing, 4-leaf stage seedling ageControl (farmers’ practice), > 7 leaf stage

Plot size was 5 x 4 m2, with a total of 15 plots at each site

Application

Granular pre-emergence herbicide Butachlor was applied @ 40 grams per 10 m2 containing 5 % Butachlor.

Urea was applied at the rate of 173.8 gm per plot, equivalent to 40 kg/ha, at 55 days after transplantation due to yellowing of the tips of leaves.

Note

The full set of SRI’s recommended practices was not assessed – only:

(a) Seedling age (younger vs. older)

(b) Wider spacing -- plant density per hill and per square meter (m2), and

(c) Water control – reduced amounts

(d) Weeding (active soil aeration) through the use of a rotary weeder was not done; a hand hoe was used to loosen the soil.

(e) Additional organic fertilization was not applied, although cattle were tethered in the fields for about 2-3 weeks prior to ploughing the field.

The results reported here are thus for partial application of SRI methodology.

Results and Discussion• 3-leaf stage seedlings spaced at 30 x 30 cm

gave the best results for all measurements • Yield-contributing parameters were higher

in SRI plots than with conventional methods

Results and DiscussionIn all three sites, SRI plots on average showed better yield performance as compared to conventional method.

Yield at three different sites calculated at 14% moisture content

Sl.No Parameters Site I Site II Site III

1 Rice variety Khangma maap Paropa Verna

2

2.12.22.32.42.5

Yield (kg/plot/Mt/ha)

20x20 3-leaf stage 20x20 4-leaf stage 30x30 3-leaf stage 30x30 4-leaf stage Control

(3.90) 5.7 (3.47) 5.2 (4.03) 6.0 (3.53) 5.3 (3.50) 5.2

(2.63) 3.9 (2.57) 3.8 (2.83) 4.2 (2.53) 3.8 (2.45) 3.6

(2.57) 3.8 (2.20) 3.3 (2.83) 4.2 (2.43) 3.6 (2.45) 3.6

Analysis of variance (RCB) for grain yield data

Sources of variation

Degrees of freedom

Sum of squares

Mean squares

Computed Fb

Tabular F

5% 1%

Replication 8 35.05 4.38 4.54** 2.67 3.97

Treatment 4 3.11 0.78

Experimental error 32 5.48 0.17

Total 44 43.64 5.33      

a cv = 9.5%b ** = Significant at 1% level of significance

Dissemination of SRI techniques

ConclusionTrials have already sparked some interest among farmers as well as researchers and extension workers. Moreover, this study would contribute to the promotion of organic farming in Bhutan. Evaluations of SRI methods at various elevations in Bhutan are continuing.

SRI Plot

Sharing SRI technique to agriculture students for multiplier effect.