Allocation of varieties and yield
of rainfed rice cultivation in
Donkhwaai village of the
Vientiane plain
Shuichi Miyagawa(Gifu Univ.),
Yoshinao Adachi(Gifu Univ.) and
Sengdeaune Sivilay(NAFRI)
1
Objectives
• Sustainability of rice cultivation system in
the village
• Actual rice yield
• Factors affecting rice growth and yield
• Eco-history of rice growth; past, present and
future
2
Where is
Xaythanii?
Where is
Donkhwaai?
3
Natural
setting of
paddy fields
School & Temple
(%)
0.3%
Paa lao (%)
15.9%
Settlement (%)
0.6%
Factory (%)
0.1%
Total Pond area
(%)
2.1%
Planted forest (%)
2.8%
Natural Forest (%)
11.0%
Field crops,
vegetable, fruits
(%)
0.0%
Lowland rice field
(%)
67.3%
Upland rice field
(%)
0.0%
4
Measurement of rice yield
Target plots
• Various landforms
= Water, Soil fertility,
• Rice varieties
= Cropping season,
Maturity
• Replication
• Owners’ permission
• Man power
5
Measurement of rice yield(2)
1.
2.
3.
4.
Cutting
Total fresh weight
Sampling
Air drying
6
Measurement of rice yield (3)
1. Dry weight of samples
2. Measuring No. of panicles and spikelets (grains)
3. Weight of sample grains and matured grains
7
Results
Seq.Plot
No.
Rep.
1
1
Sampling
date
Cultivator Variety
1 2005/10/9 nan
Kao
vieang
Noibubaan
2 2005/10/9 nan
Kao
vieang
Noibubaan
No.
panicles/ No.
No.spikelets No.spikelets/
No. hills/m2 hill
panicle/m2 /panicel
m2
31.8
4.6
147.0
75.2
11058.0
1 mean
2
2
1 2005/10/9 tao pheng Kao
Kaonoi
2 2005/10/9 tao pheng Kao
Kaonoi
2 mean
32.8
4.3
141.4
64.4
9103.0
32.3
4.5
144.2
69.8
10080.5
26.4
5.7
152.0
72.5
11020.7
27.4
4.8
130.3
80.3
10460.5
26.9
5.3
141.1
76.4
10740.6
% of ripened 1000 grains' Grain weight Straw weight Total weight Harvest
grains
weight
(g/m2)
(g/m2)
(g/m2)
index
76.0
31.3
309.6
553.8
863.4
0.4
72.2
31.6
250.8
448.3
699.0
0.4
74.1
31.5
280.2
501.0
781.2
0.4
67.5
25.7
228.0
363.8
591.7
0.4
76.1
25.9
229.6
339.6
569.2
0.4
8
71.8
25.8
228.8
351.7
580.5
0.4
Distribution of grain weight
14
12
No. of plots
10
8
6
4
2
0
0
50
100 150 200 250 300 350 400 450 500
Grain weight (g/m2)
242g/m2 in average
(2.4t/ha)
Range 99-549g/m2
9
Evaluation
Hills/m2
Grain weight (g/m2)
600
-24
r=-0.527**
500
25-29
400
30-34
300
200
35-39
100
40-
0
na
20
25
30
35
40
No. of hills/m2
45
50
N(g/m2)
600
Grain weightg/m2)
500
0
r=-0. 352*
400
0.1-0.2
300
0.3-0.5
200
0.6-0.9
100
1.0na
0
0.0
0.5
1.0
1.5
The amount of fertilizer nitrogen (g/m2)
2.0
10
Level of the yield
0.30
0.25
DD(2002-4)
Vientiane(1999-00)
DK(2005)
0.20
Frequency
• 21 plots in the
Vientiane plain
(1999-2000)
239g/m2
• 203 plots in DD
village (2002-4)
311g/m2
• 50 plots in DK
242gm2
• Attainable yields
are same.
0.15
0.10
0.05
0.00
0-
50-
100- 150- 200- 250- 300- 350- 400- 450- 500- 550Grain weight (g/m2 )
11
Adaptation by variety allocation
DD village
12
Rice varieties in DK
Medium
maturing
vars.
18%
Late
maturing
vars.
2%
Harvesting time
Early Oct.
Middle Oct.
Early Nov.
Early
maturing
vars.
80%
Planted area in whole paddy field
• Higher fields – Early maturing vars.
– Close by houses, forest
• Lower fields – Late maturing vars.
– Floating rice
13
Harvesting time and production
Grain weight
(g/m2)
350
300
250
200
150
100
Late July
Transplanting
time
50
Middle July
0
Early July
Middle Oct
Early Nov
Early Oct
• Early harvesting
= Early maturing
varieties
• = Higher yield
• = Paddy fields
near settlements
& in forest
• ←allocation
Harvesting time
14
Transition of allocation of
varieties and production
Early times
Ecological setting
Plenty water+Long
growth duration
Adaptation &
Production
Danger
Present time
Drought,
Nutrition
Late
vars.+High
prod.
Drought,
Nutrition
Salinity
Early
vars.+High
prod.
Poor soil
fertility
Early
vars.+High
prod.
Flooding
Medium, late
vars.+Low
prod.
Floating rice,
damaged
15
Studies in 2006
• Map of operating area of
individual farmer
• Map of varieties
• Map of cropping season
– Transplanting, harvesting
• Map of fertilizer
application
• Map of production
• Yield survey in sample
plots
• Rice growth and trees
(forest)
16