Cassava as an insurance crop in a changing climate: The changing role and potential applications of cassava for smallholder farmers in Northeastern Thailand

Approximately 80 percent of the 22 million people in Northeastern Thailand are engaged in agriculture, and the per capita income of the region is lower than in any other part of Thailand. The major constraint to crop production is rainfall. Although the region has an average annual rainfall greater than 1200 mm, the seasonal distribution of rainfall makes for challenging agricultural cultivation opportunities. The climate is characterized by rainy (May-October) and dry (November-April) seasons. Most (90%) farming is cultivated under rainfed conditions. In addition, most soils are characterized by a sandy texture, high acidity, low organic matter, low level of plant nutrients and low water holding capacity. Due to these conditions, and an increasingly unpredictable climate horizon, cassava has come to play an important economic role for smallholder farmers in the region. The inherent tolerance of cassava to stressful environments, requires minimal care, less investment, and provides greater flexibility in planting and harvesting. Although cassava is grown as a monoculture crop, it can also be grown profitably as a second crop in rice-based cropping systems without supplemental irrigation during the dry season, as well as intercropped in rubber plantations at early growth stages. Given the importance of cassava in farmer income, export values, marketing, and labor, this paper discusses the broader socio-economic and biophysical aspects of cassava due to its important role in future agrarian change for the region

Long-term change in rainfall distribution in Northeast Thailand: Will cropping systems be able to adapt?

Climate vagaries and the lack of irrigation, frequently combined with coarse-textured sandy and unevenly distributed saline soils, explain low crop yields and the endemic relative poverty of the rural population in Northeast Thailand (NET). Local and regional trends in agriculturally-relevant rainfall variables were investigated using the Mann-Kendall test, modified to account for serial correlation, and applied to 17 stations across NET, and the regional average Kendall's statistic. Limited changes in rainfall frequency, intensity and seasonality are observed at individual stations over the study period (1953–2004). But we found a significant regional trend toward a wetter dry season. Based on an intimate knowledge of the local farming systems, we discuss the cropping systems adaptation to these rainfall changes. If the wetting of the dry season extends in the future, as expected according to most climate projections, households would not find it difficult to adapt, except for the problems caused by temperature rise, mainly due to their renowned adaptive capacity and high mobility that historically produced diverse and resilient rural livelihood systems. (Résumé d'auteur

Impact of Agricultural Extension Services on Cereal Production among Rural Farmers in Bhutan

This study explored impact of agricultural extension services on cereal production. Data were collected through a semi-structured questionnaire from a random sample of 262 farmers from four regions (east, west, north, and south) in Bhutan. Farmers assessed the impact of extension services on five aspects of cereal production (cereal seed, social, environmental, production, and marketing aspects). Percentages and an ordered logistic model were used to analyze the data. The study found a low level of farmers’ participation in extension services. The social aspect of cereal production was the most impacted by the extension programmes, while the marketing aspect was the least impacted. The farmers’ cultivated dry land (Coeff. = 0.21) and wetland (Coeff. = 0.72), their participation in extension services (Coeff. = 0.61), and the extra labour (Coeff. = 0.24) significantly contributed to cereal production. The provision of effective and high-quality extension programs by extension agents is critical for smallholder farmers to enhance their agricultural production

Impact of Agricultural Extension Services on Cereal Production among Rural Farmers in Bhutan

This study explored impact of agricultural extension services on cereal production. Data were collected through a semi-structured questionnaire from a random sample of 262 farmers from four regions (east, west, north, and south) in Bhutan. Farmers assessed the impact of extension services on five aspects of cereal production (cereal seed, social, environmental, production, and marketing aspects). Percentages and an ordered logistic model were used to analyze the data. The study found a low level of farmers’ participation in extension services. The social aspect of cereal production was the most impacted by the extension programmes, while the marketing aspect was the least impacted. The farmers’ cultivated dry land (Coeff. = 0.21) and wetland (Coeff. = 0.72), their participation in extension services (Coeff. = 0.61), and the extra labour (Coeff. = 0.24) significantly contributed to cereal production. The provision of effective and high-quality extension programs by extension agents is critical for smallholder farmers to enhance their agricultural production

Effects of cutting length and bud removal on root yield and starch content of cassava under rainfed conditions

Bud removal of the cuttings at underground level has been claimed by cassava growers in Thailand as a method to increase cassava yield. This practise should be tested experimentally to explain the reason for yield increase. The objective of this study was to investigate the effects of bud removal and cutting length on storage root yield and starch content of three cassava varieties. Field experiment was conducted in a split–split plot design with four replications in 2010 and 2011, under rainfed conditions. Three cassava varieties (KU50, RY9 and HB60) were assigned as main plot. Two cutting lengths (15 cm and 30 cm) were assigned as sub plots, and two treatments of buds (buds cut and not cut) were assigned as sub–sub plots. The buds on the cuttings that were inserted into the soil were removed. In 2010, the plants from 15-cm long cuttings subjected to bud removal had higher fresh storage root yield (88.4 Mg ha−1) than did plants from 30-cm long cuttings subjected to bud removal (75.8 Mg ha−1). Cutting of buds also had higher fresh storage root yield (89.1 Mg ha−1) than did non bud-cutting (75.0 Mg ha−1). KU50 had the highest fresh storage root yield (91.4 Mg ha−1), dry root yield (48.4 Mg ha−1) and starch yield (20.1 Mg ha−1). Cutting length of 15 cm had higher starch concentration in storage roots (25.6%) than did cutting length of 30 cm (24.2%). HB60 had the highest starch concentration (27.0%) among cassava varieties tested. The data in 2011 were similar to the data in 2010. The responses of varieties to bud removal and cutting length are discussed

Effect of Seeding Depth and Soil Mulching on Growth and Yield of Peanut Grown after Rice in the Post-Monsoon Season of Northeastern Thailand

The experiment was conducted in a farmer's field, Ban Fang district, Khon Kaen province in 1998-1999 to investigate the effect of seeding depth and soil mulching on the growth and yield of peanut grown after rice in the post-monsoon season of Northeastern Thailand. A split plot design was used with mulching and non-mulching as main-plots and seeding depths of 5, 10 and 15 cm as sub-plots. The results showed that deep seeding at 15 cm gave the highest leaf area index, highest total dry matter yield, highest pod number per plant, heaviest 100-seed weight and highest seed yield of peanut. This was attributed to the higher root length density at a deep soil layer provided by deep seeding. Peanut roots in the deep soil layer were capable of exploring a large soil volume for water which remained available throughout the crop cycle. Mulching application showed beneficial effects on growth and yield of peanut only with shallow seeding depth (5 cm)

Growth, Yield and Land Use Efficiency of Corn and Legumes Grown under Intercropping Systems

A field experiment was conducted at the experimental farm of Khon Kaen University in 2001. The objectives of this study were to investigate growth, yield and yield components of corn, peanut, soybean and mungbean under intercropping and single cropping, as well as to assess the land use efficiency. Yield and yield components of corn was unaffected by intercropping system. In legume crops; peanut, soybean and mungbean, intercropping systems reduced the leaf area and top dry weight per plant as compared with single cropping. Grain yield of peanut, soybean and mungbean was reduced by 28%, 39% and 51%, respectively, as compared with single cropping. The pod number per plant was the most affected by intercropping among the yield components. However, corn-legume intercropping increased land use efficiency by 48% to 66% depending on legume species. Corn-peanut intercropping gave the highest land use efficiency. The effects of light penetration and nutrient competition are discussed

Effects of soaking seed and fertilizer placement on growth and yield of soybean grown after rice in the post-monsoon season in Khon Kaen Province

The experiment was conducted in a farmer’s field in Ban Fang District, Khon Kaen Province in 1999- 2000. The objective of this study was to investigate the effect of soaking seed in water or not soaking before seeding, and fertilizer placement (surface broadcast at seeding, banding below the seed at seeding and banding beside the plant row 10 days after seeding) on growth and yield of soybean grown after rice in the postmonsoon season. The results showed that soaking seed before seeding had no significant effect on leaf area per plant, total top dry weight, root length density, pod number per plant, seed number per pod, 100-seed weight and seed yield of soybean. However, soybean growth, yield components and seed yields tended to be higher with no soaking. Therefore, soaking seeds in water before seeding had no advantage over no soaking in terms of early emergence and early maturity before the plant was subjected to water stress at grain filling phase. Fertilizer placement had a significant effect on growth nd yield of soybean. Banding application gave higher leaf area per plant, total top dry weight, root length density, pod number per plant and seed yield than those of broadcast application. Banding generally increased leaf N, P and K concentration. There was no significant difference in seed yield between belowband and sideband application. Belowband application tended to produce higher seed yield than that of sideband application. Belowband application at planting saved labour as compared with sideband application. To obtain a satisfactory yield of soybean grown following rice in the post-monsoon season during the rainless period, however, shallow depth of groundwater table to provide upward movement of water to the root zone should be considered