Msanya, Balthazar M.2025-09-112025-09-111987https://www.suaire.sua.ac.tz/handle/123456789/6976ThesisIn many countries a lot of soil resource inventories (SRIs) particularly soil surveys have been made and are still being made. Their objectives are generally well stipulated and known, yet there are indications that these documents are not sufficiently being used both in developing and developed countries. It is against this background that the present study was started. The intention has been to look for ways of characterizing SRIs and to evaluate their adequacy for specified land uses. This way it was hoped that reasons behind the limited use of such documents could be identified and hence help to frame recommendations for future soil inventories. The data base in this study comprises (a) a total of 176 soil survey reports (including accompanying maps) from 46 countries, (b) 70 70 completed questionnaires from soil surveyors representing 40 countries and (c) 94 completed questionnaires from users of soil maps and reports representing 35 countries. Using the 176 SRIs, a general inventory of the documents was made as a first attempt to characterize them. Then indices to characterize the SRIs in terms of their cartographic attributes were developed. These indices were highly correlated with each other. Other observations on cartographic attributes indicated that (a) the concept of map linear reduction factors is not consistently used and (b) information on soil description sites is only rarely given in SRIs. In relation to the information content of map legends and soil reports it was observed that (a) most SRIs are produced by free survey method; (b) the most commonly used attributes in soil mapping are texture, drainage, landform, topography, parent material and soil depth; (c) information on density of field observations is often lacking in SRIs and is commonly vaguely presented; (d) USDA and FAO/Unesco classification systems are the most widely used internationally; (e) most SRIs contain interpretive data and (f) information on purity of mapping units is often not given in SRIs and in many cases only partly presented. Two methods are developd and described for estimating the utility of base maps. It was noted that many SRIs do not bear information about their compliance with specified base map accuracy standards. With regard to general legibility of SRIs, it was observed that (a) provision of instructions on how to use the SRIs is mostly neglected and (b) glossary of specialized terminology and ranges of soil properties of mapping units are commonly not provided in the documents. A method is developed and described for characterizing and systematically evaluating information given in map legends and soil reports about mapping units in function of specified land uses. Furthermore, a comprehensive method is also described for the assessment of the predictive adequacy of SRIs for three land uses in function of (a) cartographic attributes, (b) map legend and soil report attributes and (c) base map attributes. Guidelines outlining the assessment procedure are provided. This method was applied on 66 selected semi-detailed and detailed SRIs from 17 countries. Following strictly the stipulated criteria of adequacy it was found that only about 27 « of the documents are completely adequate for predicting performance of both corn and oil palm, and about 30 % can be considered adequate for predicting performance of Eucalyptus deglupta (forestry). A preliminary study on the adequacy for prediction of soil erosion hazards was done on 50 selected SRIs from 18 countries, Based on the adequacy criteria per se, it was found that most of the documents could be said to be adequate for the use in question, It was also noted that (a) although information on climate is given in all documents, winds are frequently not described; (b) information on topography is normally limited by the lack of contour lines printed with soils information or the lack of contour maps appended to the soil maps and (c) information on soil permeability is often not described. Analysis on the answers given by respondents of the questionnaire to soil surveyors shows that (a) soil surveyors to a great extent determine the nature of SRIs to be made and only occasionally do users have the opportunity to do so; (b) some terminologies and criteria used in soil survey eg. soil survey intensity, field soil mapping procedures and purity of mapping units are not conceived and used consistently; (c) most soil surveyors do not monitor utility of the SRIs they make; (d) soil maps are sometimes too complicated and (e) publicity about SRIs has not sufficiently been made. The results from the questionnaire to users of soil maps and reports indicate among other things that (a) soil surveys are still considered very important in development projects; (b) there are problems of knowing about the existence of soil maps, yet communication media such as radio, television and newspapers have not been used significantly to ameliorate the situation; (c) major problems encountered while using soil maps and reports include poor legibility, problems of location on the maps, use of vague and in some cases complicated terminology, A revised questionnaire to users of soil maps and reports has been proposed to accomodate changes that will take it more useful as a source of information. To put everything in a nutshell, it can be said that indeed, existing SRIs do present serious bottlenecks that need attention in future inventories. For this a series of recommendations has been suggested at various levels of the study.enSoil resourcesSoil surveysSoilThesis