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Contents & Foreword, Characterizing And ... - IRRI books

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Table 4. Parameters used in some published rainfed rice environmental characterizations and analysisat different scales.Scale of analysis/characterization Geographical Environmental characteristics/and rice area area parameters studied ReferencecoveredMega South and ● Rainfall in 5-mo growing season Garrity et al (1986)(30 million ha) Southeast ● No. of months R>PE + 20%Asia ● Soil textural class● Slope class● Soil units (physical and chemicalcharacteristics and constraintssuch as low CEC, high P fixation,alkalinity and salinity, Zndeficiency; organic, acid sulfate,and shallow soilsMega Eastern India ● Irrigation <strong>IRRI</strong> (1993)(26.8 million ● Water depthha) ● Land formMacro (–) Bangladesh ● Various soil physical and chemical Ahmed et al (1992)properties● Land use● Rainfall FAO (1988)● Length of growing season● Crop establishment techniques● Water qualityMacro Eastern India ● Rice yield reductions due to major Widawsky and O’Toole(10.6 million ha) biophysical stresses (1990), <strong>IRRI</strong> (1993)● Drought● Flooding pattern● Water balance● Length of growing season● Rice yieldMacro Côte d’Ivoire ● Rainfall WARDA (1992)(329,000 ha) ● Toposequence position● Tillage method● Rice variety, sowing, and intercroppingtechnique● Land tenure● Decision-making by gender● Production objectiveMeso Bahraich ● Land form Singh and Pathak(200,000 ha) District, India ● Physiography and slope (1990), <strong>IRRI</strong>● Soil texture (1992, 1996)● Soil fertility● Water sources● Irrigationcontinued on next page<strong>Characterizing</strong> rainfed rice environments: an overview . . . 9

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