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e classified as low for a rainfed ecosystem (Garrity et al 1986). The situation isexacerbated by drought spells of 1 or 2 wk within a month, which, depending on theirtiming, can drastically affect crop yield.As both technical and economic constraints limit further irrigation developmentin Bangladesh, the majority of the farmers in rainfed systems will certainlycontinue to remain in the drought-prone environment in the foreseeable future. Technologiesfor drought alleviation are now available and are gradually being acceptedand adopted by farmers in rainfed lowlands. Drought alleviation is possible by switchingfrom the traditional transplanting method of crop establishment (TPR) to dryseeding (DSR) in which rice seeds are sown on dry-tilled unsaturated fields early inthe season. These fields may subsequently become flooded with the onset of the monsoonrains. Studies on DSR in the Philippines (Saleh and Bhuiyan 1995, Lantican etal 1999) have shown that DSR uses rainfall more efficiently and suffers less droughtrisk than TPR. On-farm reservoirs for supplementary irrigation have also been usedeffectively for drought alleviation in the Philippines (Moya et al 1986) and in India(Paul and Tiwari 1994). But, before planning and recommending such interventionsfor drought alleviation in a rainfed ecosystem, a systematic and quantitative analysisof drought is imperative.This study is an attempt in that direction with the specific objectives of (1)characterizing the area in terms of agrohydrology, (2) studying the nature, extent, andfrequency of droughts during the aman season from long-term rainfall data, and (3)studying the relative merits of dry seeding over transplanting of rice in terms of droughtalleviation.Materials and methodsAgrohydrologic settingThe field study was carried out at Rajabari Union of Godagari Thana of RajshahiDistrict, in the Barind Tract of northwest Bangladesh. The Barind Tract has an undulatingtopography with gray terrace soil and an average elevation of 43 m above sealevel. The soil texture varies from silt loam to silty clay loam and is poorly drainedwith a 6–8-cm thick plow pan at 9–11-cm depth (Mazid et al 1998). The soil is low inorganic matter (0.8–1.2%) and is acidic (pH from 5.5 to 6.5).Annual rainfall at Godagari averages about 1,300 mm and about 80% of it isconfined to the monsoon months of June to September. The average daily evaporationat Rajshahi, located centrally within the Barind Tract, varies from 2.3 mm inJanuary to 6.3 mm in April. The four months when the rainfall exceeds evaporationare June to September. The maximum and minimum temperatures at Rajshahi averageabout 39 °C and 10 °C, respectively, and occur in April and January.The predominant cropping pattern in the area is transplanted aman rice–fallow.In some areas, chickpea, linseed, barley, and other crops are grown either as a monocropor as a mixed crop during the rabi (dry) season.234 Saleh et al