1. 1 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)

2. 2 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

3. 3 Where is Xaythanii? Where is Donkhwaai?

4. 4 Natural setting of paddy fields

5. 5 Measurement of rice yield Target plots Various landforms = Water, Soil fertility, Rice varieties = Cropping season, Maturity Replication Owners’ permission Man power

6. 6 Measurement of rice yield(2) 1.Cutting 2.Total fresh weight 3.Sampling 4.Air drying

7. 7 1.Dry weight of samples 2.Measuring No. of panicles and spikelets (grains) 3.Weight of sample grains and matured grains Measurement of rice yield (3)

8. 8 Results

9. 9 Distribution of grain weight 242g/m 2 in average (2.4t/ha) Range 99-549g/m 2

10. 10 Evaluation r=-0.527** Hills/m 2 -24 25-29 30-34 35-39 40- na N(g/m 2 ) 0 0.1-0.2 0.3-0.5 0.6-0.9 1.0- na r=-0. 352*

11. 11 Level of the yield 21 plots in the Vientiane plain (1999-2000) 239g/m 2 203 plots in DD village (2002-4) 311g/m 2 50 plots in DK 242gm 2 Attainable yields are same.

12. 12 Adaptation by variety allocation DD village

13. 13 Rice varieties in DK Higher fields – Early maturing vars. –Close by houses, forest Lower fields – Late maturing vars. –Floating rice Harvesting time Early Oct. Middle Oct. Early Nov.

14. 14 Harvesting time and production Early harvesting = Early maturing varieties = Higher yield = Paddy fields near settlements & in forest ←allocation

15. 15 Transition of allocation of varieties and production Early times Present time Late vars.+High prod. Early vars.+High prod. Medium, late vars.+Low prod. Salinity Flooding Poor soil fertility Drought, Nutrition Plenty water+Long growth duration Floating rice, damaged Drought, Nutrition Ecological setting Adaptation & Production Danger

16. 16 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)