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

Table 6. Major constraints to agricultural developmentof inland valleys in West Africa.ConstraintRanking aWeeds 4.7Lack of water control 4.7Lack of inputs 4.6Labor shortage 4.4Crop diseases 4.3Lack of credit 4.3Nutrient status 4.2Land tenure 4.1Poorly adapted varieties 3.9Soil erosion 3.7Soil structure 3.6Insects/pests 3.6Marketing 3.6Iron toxicity 3.4Acidification 3.2Land clearing 3.2Human health 3.1a On a scale of 1–5, where 1 = not important and 5 =very important.Source: Jasmin and Andriesse (1993).ration. A change in temperature regime may also lead to changes in rainfall and itsdistribution and cloudiness and its distribution, and thus solar radiation, wind speed,and biological activities in the soil-air-plant system. These factors have large effectson rice growth, development, and yield.Major issues in characterizing rice environmentsExperiences gained in characterizing and classifying rice production environments inthe past could provide insights for future exercises in this domain. The following aresome of the issues that future activities in characterizing rice production environmentsmay have to consider.The universality and compatibility of the systems usedTable 2 shows that the bases used in many systems for classifying and characterizingrice production environments before the mid-1980s were not similar. This lack ofuniversality has limited the usefulness of environmental classification and characterization,at least in terms of collaboration among rice research institutions and scientiststo develop and transfer rice technologies. This was perhaps the main reason forIRRI to establish the International Committee on Terminology of Rice Growing Environmentsin 1982.Characterizing environments for sustainable rice production 47