Constraints to Rice Production Systems in Laos J.M. Schiller1*, B. Linquist1, K. Douangsila2, P. Inthapanya2, B. Douang Boupha2, S. Inthavong3 and P. Sengxua2 Abstract In 1999, total rice production in Laos was more than 2.1 million tonnes, enough to make the nation self-sufficient in rice. Over the past 2 decades, total production has increased by about 100%, with most of the increase occurring in the rainfed lowlands where production jumped from 705 000 t in 1980 to 1 502 000 t in 1999. Even though the dry-season irrigated environment has increased production by almost nine times in the past decade (from 41 000 t in 1990 to 354 000 t in 1999) and further small-scale irrigation schemes are planned to achieve a total dry-season irrigated area of about 180 000 ha by 2005, the wet-season lowland environment will remain the most important rice-producing environment for the foreseeable future. Higher yields and reduced year-to-year variability in production can be expected with further intensification of production systems in the lowlands. However, further improvements in production will depend on higher levels of inputs and continued alleviation of some production constraints. The uplands will become less important for rice production as alternative, more sustainable technologies are developed to replace the current ‘slash-and-burn’ and shifting cultivation practices. This paper summarizes the known main abiotic and biotic production constraints in each of Laos’s rice-producing environ- ments: wet-season lowlands, dry-season irrigated, and rainfed uplands, but not those socioeconomic constraints that can also have significant impact on farmer attitudes and production. The major pro- duction constraints in the main rice-producing environment—the wet-season lowland ecosystem of the Mekong River Valley—are drought and poor soil fertility. However, more than 10% of the wet- season lowlands in the central and southern agricultural regions are also regularly affected by flooding of the Mekong River. In these areas, flood damage is often regarded as a greater produc- tion constraint than drought. In the dry-season irrigated environment, poor soil fertility is the main abiotic constraint. Insect pests are becoming increasingly important in both these production sys- tems. In existing production systems in the rainfed uplands, the main constraints are, in decreasing order of significance, weeds, rodents and drought. Farmers’ perceptions of the relative importance of production constraints in the uplands are generally more accurate than those in the lowlands. Poor soil fertility is often not rated among the most important constraints in the wet-season low- lands and dry-season irrigated environments, despite experimental evidence that often the greatest yield increases can come from improved plant nutrition. Until recently, farmers’ perceptions of the importance of insect pests in the lowlands often exaggerated their economic significance. RICE is the single most important crop in Laos. In land. About 83% of rice production came from low- 1999, the area planted to rice was about 717 600 ha, land and upland cropping during the wet season, representing more than 80% of the nation’s cropped with the lowland ecosystem accounting for about 67% of the total area and 71% of production and the 1 Lao–IRRI Project, Ministry of Agriculture and Forestry, upland systems for 21% of the area and 12% of pro- Vientiane, Laos duction (Figure 1). 2 National Agriculture and Forestry Research Institute, Total rice production in 1999 was more than 2.1 Ministry of Agriculture and Forestry, Vientiane, Laos 3 Agriculture and Forestry Services Office, Savannakhet million tonnes (Table 1)—this was the first year that Province, Laos production had reached or exceeded such a number. E-mail: [email protected] The level was regarded as sufficient to meet the *Corresponding author country’s immediate grain needs. KEYWORDS: Production systems, Constraints, Abiotic, Biotic, Technologies. 3 Increased Lowland Rice Production in the Mekong Region edited by Shu Fukai and Jaya Basnayake ACIAR Proceedings 101 (printed version published in 2001) (a) Area planted to rice in Laos, 1999 have also supported the development of the Lao national rice research program. Rainfed uplands (21%) (153 371 ha) The impact of the research output has been greatest through the development and adoption of improved varieties in the wet-season lowland and Irrigated environment (12%) dry-season irrigated production systems. Between (87 030 ha) 1991 and 1999, the adoption of improved varieties in the wet-season lowlands of the main rice-producing area of Laos—provinces in the Mekong River Valley—increased from about 5% to 70% of the area Wet-season lowlands (67%) (Schiller et al. 2000a). Most of these varieties are (477 176 ha) Lao improved glutinous varieties. Research in other areas has highlighted a range of (b) Rice production in Laos, 1999 other production constraints in each rice-producing Rainfed uplands (12%) environment that, if alleviated, would probably result (246 790 t) in substantial yield improvements and reduced year- to-year variability in production. Laos may well be Irrigated environment (17%) (354 000 t) able to considerably increase its rice production, thus increasing its annual rice surplus available for either export and/or the maintenance of a national rice reserve. The main production constraints for each of the three rice-producing environments of Laos are Wet-season lowlands (71%) (1 502 025 t) summarized below. Figure 1. Area planted (a) and production (b) in the rice- Wet-Season Lowlands growing environments of Laos, 1999. About 84% of the rice-growing area in the wet- season lowlands is located in the central and southern Between 1976 and 1999, the area planted to the agricultural regions, mainly in provinces lying in the main wet-season lowland crop increased by 50%, Mekong River Valley (Table 1). Savannakhet from about 317 000 to about 477 000 ha. Production Province, in the lower central agricultural region, has increased by more than three times, from about the largest area of wet-season lowland rice of any 455 000 to 1.5 million tonnes (Table 2). However, in single province, encompassing 103 400 ha in 1999 percentages, the greatest expansion in area and pro- (22% of the total area). Despite a significant expan- duction over this period took place in the dry-season sion of the dry-season irrigated area, the wet-season irrigated environment, from 2700 ha, producing 3500 lowland environment will remain the most important tonnes, in 1976 to 87 000 ha, producing 354 000 ecosystem for rice cultivation in the foreseeable tonnes, in 1999. For the rainfed uplands, official future. statistics from the Lao Ministry of Agriculture and Forestry show that the area planted to upland rice Abiotic constraints reached a peak in the early 1980s (almost 300 000 ha), Droughts and floods with a subsequent steady decline during the 1990s (Table 2). This decline partly reflects official govern- With most of the planted area under rainfed con- mental policy to replace all upland rice production ditions, annual rice production is highly susceptible based on ‘slash-and-burn’ and shifting cultivation to climatic variability. The rainfall pattern throughout systems with more sustainable production practices. the country is weakly bimodal with a minor peak in In 1999, the area under upland rice cultivation was May and early June and a major peak in August and September. About 75% of the rainfall is received about 153 000 ha, producing almost 247 000 tonnes between May and October (Figure 2). In some of the (about 12% of total production). more northern provinces (e.g. Sayabouly and Luang Systematic research aimed at improving produc- Prabang), the total annual rainfall drops to between tivity in the different rice production systems of Laos 1200 and 1300 mm. In most provinces of the Mekong began in 1991 with support from the Swiss Govern- River Valley, rainfall ranges from about 1500 to ment through the International Rice Research Insti- 2200 mm. The rainfall pattern can vary from year-to- tute (IRRI). In recent years, several other agencies year, causing large fluctuations in rice production. 4 Increased Lowland Rice Production in the Mekong Region edited by Shu Fukai and Jaya Basnayake ACIAR Proceedings 101 (printed version published in 2001) Table 1. General rice production statistics for Laos, 1999. No: Region and province 1999 Wet-season lowland 1998/99 Dry-season irrigated 1999 Wet-season rainfed upland Total 1999 Harvested Yield Production Harvested Yield Production Harvested Yield Production Harvested Yield Production area (ha) (t ha–1) (t) area (ha) (t ha–1) (t) area (ha) (t ha–1) (t) area (ha) (t ha–1) (t) I Northern Region 73 034 3.30 241 304 7 925 3.36 26 650 113 358 1.62 183 906 194 317 2.33 451 860 Increased LowlandRiceProductioninthe MekongRegion 1 Phongsaly 5 747 3.26 18 761 115 3.13 360 15 800 1.57 24 802 21 662 2.03 43 923 2 Luang Namtha 7 485 3.30 24 692 860 3.40 2 921 11 200 1.64 18 410 19 545 2.35 46 023 3 Oudomxay 8 731 3.23 28 205 890 3.62 3 222 24 201 1.64 39 805 33 822 2.11 71 232 edited byShuFukai and JayaBasnayake (printed versionpublished in2001) 4 Bokeo 9 775 3.35 32 740 210 3.34 702 5 280 1.65 8 720 15 265 2.76 42 162 5 Luang Prabang 9 677 3.31 32 050 2 280 3.40 7 745 32 000 1.65 52 813 43 957 2.11 92 608 ACIAR Proceedings 101 6 Huaphanh 11 285 3.30 37 252 1 525 2.99 4 557 12 657 1.58 20 050 25 467 2.43 61 859 7 Sayabouly 20 334 3.32 67 604 2 045 3.49 7 143 12 220 1.58 19 306 34 599 2.72 94 053 II Central Region 271 422 3.19 864 975 55 710 4.15 231 300 26 904 1.60 43 046 354 036 3.22 1 139 321 5 1 Vientiane M.