The use of vetiver for soil erosion prevention in cassava fields in Thailand

Abstract: Cassava is a crop that induces high rates of soil erosion, especially if grown in sloping sandy soils. The joint research of the Centro Internacional de Agricultura Tropical (CIAT), the Department of Agriculture (DOA), and Kasetsart University (KU) revealed that adjustments in planting methods or planting systems could reduce soil erosion. Each method has certain advantages and disadvantages. While some methods give extra income, others need more management or higher investments; thus it is not certain whether farmers would adopt any of these methods.Therefore, CIAT in collaboration with the Department of Agricultural Extension (DOAE) and DOA initiated a project, entitled “Enhancing the Adoption of Soil Erosion Control Practices in Cassava Fields ” in order to work with cassava farmers, using a Farmer Participatory Research (FPR) approach. During the first phase (1994-98) of the project. two pilot sites were selected at Soeng Saang district of Nakhon Ratchasima province, and in Wang Sombuun district of Sra Kaew province. FPR trials on methods to reduce soil erosion were conducted for three consecutive years. After narrowing down the number of suitable options, farmers in both sites finally selected and adopted the contour strip cropping of cassava with vetiver hedgerows. They also requested furthe

Working with farmers : The challenge of achieving adoption of more sustainable cassava production practices on sloping land in Asia

Farmers in Asia like to grow cassava because the crop will tolerate long dry periods and poor soils, and will produce reasonable yields with little inputs. Most farmers realize, however, that cassava production on slopes can cause severe erosion, while production without fertilizer inputs may lead to a decline in soil productivity. Research has shown that cassava yields can be maintained for many years with adequate application of fertilizers, and that there are various ways to reduce erosion. Adoption of erosion control practices, however, has been minimal as farmers generally see little short-term benefits of these practices. To enhance the adoption of soil conserving practices and improve the sustainability of cassava production, a farmer participatory research (FPR) approach was used to develop not only the best soil conservation practices, but also to test new varieties, fertilization and cropping systems that tend to produce greater short-term benefits. Th

Cassava extension organization and activities in Thailand

Being easy to grow and drought tolerant, cassava is a popular crop among Thai farmers, particularly in the Northeast and East. The area planted annually is 1.28-1.60 million hectares. Because of drought and infertile soils in these areas, cassava yields average only 13-14 t/ha with about 18 percent starch. The price of fresh roots is about US$28-30/tonne. In the past only the local varieties were grown all over the country. In 1984, a better variety, Rayong 3, was introduced to the farmers. It is characterized not only by high yield but also by high starch content. Later, other new varieties have been released by the research institutes and universities. The government has therefore allocated a budget to multiply and promote new cassava varieties. This long-term program started in 1993 and will continue until 1998. Due to changes in the Common Agricultural Policy of the European Economic Community, the government policy makers expect that the cassava price in the EEC will decline. The government is therefore making an effort to reduce the cassava area by promoting the production of other perennial crops. Also, a large government budget has been provided to survey the potential area for cassava crop substitution. The future target of our program is for average cassava yields to increase to about 14.5 t/ha, while the recommended varieties will be cultivated in about 20 percent of the total cassava area by 199

Maintaining the edge: the case of cassava technology transfer in Thailand

For more than two decades Thailand has built up an intensive and highly profitable cassava processing and export industry, mainly due to favorable price and quota policy regimes with the European Community (EC). During the 1980`s however, internal EC political pressure has attempted to reduce Thai pellet imports through various measures. Moreover, in 1993 internal EC grain prices were lowered substantially, thereby reducing the relative price advantages of Thai cassava as energy substitute. The subsequent pressure on the Thai cassava sector has resulted in several Thai governmenlal policy measures: (a) reduce cassava area using EC subsidies, (b) diversify cassava products and markets, and (c) reduce cassava production cost through increased varietal technology transfer. To stimulate the latter, significant private (processors) and government funds have been directed to cassava varietal technology transfer. The paper examines adoption characteristics of cassava variety RAYONG 3 (R3) and analyzes with a logistic regression model the different factors that influence (non) adoption based on survey data of 700 cassava farm households in 9 provinces of NE and E Thailand. Results show that both the government and the private cassava sector have played a key role in the technology diffusion process. Hence, this will help to maintain the competitiveness of cassava for export markets

Farmer participatory research in soil management and varietal selection in Thailand

A pilot project on the use of Farmer Participatory Research (FPR) methodologies with the objective of enhancing farmer adoption of practices that minimize soil erosion in cassava-based cropping systems, was conducted jointly by DOA and DOAE with technical and financial support from CIAT in two sites in Nakhon Ratchasima and Sra Kaew provinces. The activities involved a preliminary survey using RRA methodologies, the setting out of demonstration plots, as well as farmers meetings and farmers field trips to observe the demonstration plots. The activities also included conducting various types of FPR trials with farmers on their own land and organizing a farmer's field day to harvest these trials, to discuss the results, and to select the best treatments for next-year's trials. The results revealed that the highest yield of cassava in Soeng Saang district of Nakhorn Ratchasima province was obtained from planting contour barriers of vetiver grass within cassava plots; this practice also resulted in the lowest level of soil erosion. On the contrary, in Wang Nam Yen district of Sra Kaew province, the highest cassava yield was obtained in plots with upand-down ridging, while the lowest level of soil erosion was observed with contour ridging. However, from the discussion between participating farmers and FPR team members it was concluded that the planting of contour barriers of vetiver grass was the most effective method to reduce erosion in the long-term, even though this treatment neither had produced the highest yield of cassava nor the highest income. Within the same pilot project, FPR trials on cassava varieties and on rates of fertilizer application were conducted in order to motivate farmers to participate m the project. In Wang Nam Yen district, Rayong 90 had the highest yield and ranked second in starch content, while Rayong S had the second highest yield but the highest starch content. In Soeng Saang district, Rayong 90 ranked first in yield and starch content, while Kasetsart 50 ranked second in both yield and starch content. With respect to the fertilizer trials, it was found that in Soeng Saang district the application of 156 kg/ha of 15-15-15 resulted in both the highest yield of cassava and highest net income

Varietal improvement and dissemination by Ksatsart University, the Thai Tapioca Development Institute and the Dept. of Agricultural Extension

For decades a cassava yield stagnation has been observed in Thailand. In addition, current prices of cassava roots and products are highly fluctuating, as they depend on the European Union market's price of cereals, the subsidy of which will be relaxed and will soon disappear. Since 1992 the Thai government has been implementing a policy of reducing the cultivated area, while maintaining the quality and total production of cassava, by the replacement of the traditional local variety, Rayong 1 , by higher yielding new varieties. The objective of this paper is to describe the varietal improvement of cassava by Kasetsart University (KU), as well as the cooperative multiplication and dissemination of new, improved cultivars to farmers by KU, the Thai Tapioca Development Institute (TTDI) and the Department of Agricultural Extension (DOAE). Two popular cassava cultivars, Kasetsart 50 and Rayong 5, were officially released in 1992 and 1994, respectively. Subsequent breeding efforts at KU have concentrated on the cross between Rayong 5 and Kasetsart 50. The preliminary results shows that several F, clones from the cross had potential dry root yields 10-30% higher than those of the parents. These promising clones have harvest indices and root starch contents similar to those of the parents, but have a significantly higher total biological yield. Regarding varietal dissemination, in 1994 KU produced 750,000 long stems, and in 1995 1.5 million long stems of Kasetsart 50, for the DOAE to distribute to cassava fanners for further multiplication and distribution. Participating farmers received free cassava stems and 15-15-15 fertilizer at the rate of 625 kg/ha. In 1994, the multiplication area was 5,440 ha involving 2,458 farmers from 25 provinces. Additionally, in 1995, there were 3,899 participating farmers from 22 provinces, who multiplied cassava in 6,274 ha. In 1993, the TTDI was founded as a foundation, with an initial trust fund of US$24 million. Later, in 1995 TTDI cooperated with KU in distributing 1.79 million stems of Kasetsart 50 to 1,198 cassava farmers from 11 provinces, while 5.97 million stems of Kasetsart 50 and 484,000 stems of Rayong 5 were distributed in 1996 to 4,243 cassava farmers from 23 provinces. Subsequently, in 1995, farmers who planted Kasetsart 50 indicated very satisfactorily performance of this new variety. An average yield of 26.47 t/ha was obtained by 26 surveyed fanners who planted Kasetsart 50, as compared with the national average yield of 14.6 t/ha