IMPROVING RICE BASED UPLAND CROPPING SYSTEMS

Increasing population pressure is reducing fallow periods in the traditional slash-and-burn rice based upland systems of the Lao PDR. Short fallow periods have rendered these systems unsustainable as soil erosion, weed pressure and labour inputs have increased; and soil fertility and yields declined. The end result is lower returns on productivity and increased poverty. This situation has created a demand from both farmers and government agencies for sustainable agricultural technologies to improve upland farmer livelihoods. Over the years considerable research effort has been devoted to the development of sustainable upland technologies, however, adoption by farmers has been limited. One reason for slow adoption is the high diversity encountered in the uplands. There is considerable biophysical diversity (as seen in differences in climate and soils), socio-economic diversity (such as ethnic and cultural diversity and large differences in opportunities and constraints between individual households) and market diversity (particularly market opportunities and market access). With such diversity, technology recommendations will necessarily be site specific. This diversity necessitates the use of participatory and adaptive research approaches through which researchers and farmers can develop technologies suited to local conditions. The authors’ objective is to develop more productive and sustainable upland rice-based cropping systems. Ensuring rice sufficiency at the local level will allow for greater diversification in other upland fields. A multifaceted, participatory and adaptive research approach has been used to develop sustainable upland systems, which has resulted in the development of a number of technologies. First, superior upland rice varieties were identified. Traditionally, local upland rice varieties grown in Laos have been selected for their performance under favourable conditions with long fallow periods and, as such, are not well suited to short fallow conditions. Through a participatory variety selection (PVS) programme, two upland rice varieties have been identified which yield 0.3 0.5t/ha more than local check varieties (an 18-27% increase in yield). Second, improved rotational systems that address problems related to weeds, soil fertility and declining yields are being developed and tested by farmers. Depending on population pressure, potential cropping systems range from extensive (for farmers that still rotate fields) to intensive continuous cropping on the same piece of land. Examples of extensive systems are rattan, paper mulberry and pigeon pea rotated with rice on a three-year cycle. Intensive systems involve continuous cropping rotations with dry season fallows. This paper discusses these technologies in greater detail as well as the process by which these technologies were developed. 300 NAFRI Workshop Proceedings Upland rice systems in Laos systems in peril Rice is the most important crop in Laos and accounts for about 70% of total calorie intake across the nation (Maclean et al., 2002). Although at the national level Laos is sufficient in rice, northern Laos suffers a rice deficit, a situation that has either not improved since 1975 (figure 1) or is getting worse (ADB, 2001). This deficit is linked with increasing population pressure. Population pressure is increasing due to natural causes, but also due to village migration and land allocation policies, which have increased population pressure on limited land resources, especially along roads. Such pressures are putting stress on the fragile slash-and-burn agricultural systems in much of northern Laos resulting in declining upland rice (staple crop) yields and increasing poverty. Upland rice is the main crop grown in the highlands of northern Laos where rice is grown in slash-and-burn systems. The normal rotational system for upland rice in slashand-burn systems is a single year of rice followed by two or more years of natural or weedy fallow. Traditionally, fallows have been for up to 40 years but increasing population pressure is often reducing fallow periods in these systems to only two years. While it is not possible to provide a general figure for a minimum sustainable fallow period, all would agree that two-year fallows are not sustainable under current management practices. Short fallow periods have rendered these systems unsustainable as soil quality (due to nutrient depletion and erosion) is worsening, weed pressure and labour inputs are increasing and yields are declining with the end result being lower returns on productivity and increased poverty. This is supported by numerous surveys where farmers report that rice yields are declining and rice deficits are increasing. Since rice sufficiency is strongly associated with well-being, poverty is increasing as a result of short fallows (ADB, 2001). In upland rice systems short fallows are resulting in a heavy investment in weeding. Farmers need to weed up to five times per season when the fallow is two years or less, compared with twice in a ten-year fallow (figure 2). Weeding alone accounts for about 50% of the total labour requirement of rice (150 person days/yr or more). These issues have created a demand from farmers and government agencies for alternative agricultural solutions. Such solutions could either be: Improved rice production systems Alternative cash crops that allow for income generation and cash to buy rice. Experiences from other Asian countries suggest that farmers are much more likely to diversify into other crops once they have achieved self-sufficiency in rice. Thus rice sufficiency is a platform for diversification. Lao-IRRI and NAFRI have been working together since 1991 to develop sustainable rice based systems. Research has focused on improving productivity and developing highland paddies (discussed by Pandey et al., in this book) as well as upland rice based systems. The following paper discusses the problems, challenges and progress to developing improved upland rice based systems. Intensification of rice based systems Land use and labour intensify as systems move from traditional slash-and-burn systems with forest fallows to annual cropping systems (figure 3). In Laos, traditional upland rice production practices have not changed despite shortening fallows, and this Shifting Cultivation and Poverty Eradication in the Uplands of the Lao PDR 301 has led to declining productivity. Research is necessary to identify improved cropping systems that are sustainable under the current land management practices. Where villages have undergone land allocation, farmers typically have three plots of land; therefore the maximum fallow is two years. In alignment with this policy, research has focused on developing alternative upland rice based systems for zero (annual cropping) to two-year fallows. A multifaceted research approach is used that combines the development of suitable varieties with alternative rice based cropping systems (figure 3). Alternatives for short fallow systems Varieties Traditional upland rice varieties are grown extensively in the uplands of Laos, in fact, there are no known improved upland varieties being grown. The diversity of varieties is high with most villages growing 10 to 20 different varieties and a single farmer growing two or three varieties on average (Appa et al., 2002). These varieties have been selected for long fallow conditions and are generally not suited to the short fallows that many farmers are currently experiencing. Since 1991, the Lao-IRRI project has been collecting and preserving traditional Lao rice varieties. There are currently over 13,000 accessions in the Lao gene bank, with about half of these being upland rice varieties. The variety improvement program is screening these varieties to identify early and medium duration varieties that are suited to short fallows. Final testing and evaluation of varieties is done through participatory variety selection (PVS) trials under farmer management. Such trials have been conducted in all the northern provinces of the Lao PDR. Through this programme, two upland rice varieties (Nok and Makhinsoung) have been identified which yield 0.3 0.5t/ha more than local check varieties which is an 18-27% increase in yield (figure 4). Nok is an early duration variety that has good yields and receives high farmer preference ratings due to its large seed and panicle, ability to perform in poor soils and high quality (aroma and softness). Makhinsoung is a medium duration variety that also receives high farmer preference ratings although the grain quality is lower than Nok. While much of the research has focused on glutinous rice varieties, the programme has started evaluating non-glutinous rice varieties that may be more preferable to certain ethnic groups. These varieties come both from Laos and other countries. On-farm testing began in 2003. Cropping systems For systems with only two or three-year fallows to be sustainable, some form of fallow enrichment is required. Shrubby legumes are often suggested as possibilities as they add nitrogen to the system by nitrogen fixation and other nutrients due to deep rooting depths. Farmer participatory research began in 2001 by testing a number of promising fallow species: leucaena (Leucaena leucocephala) pigeon pea (Cajanus cajan) 302 NAFRI Workshop Proceedings paper mulberry (Brousonnetia papyrifera). crotalaria (Crotalaria anagyroides). All are legumes except paper mulberry, which was included since it is an indigenous fallow crop in northern Laos. Crotalaria and pigeon pea performed the best in the first year (data only available for fallow species establishment) but farmers preferred paper mulberry and pigeon pea because of the potential economic benefits, especially paper mulberry (table 1). Based on these results, the requirements of a good fallow or rotational species are that it: Provides some economic benefit. Is easy to grow and maintain