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Africa Irrigation Potential, Best soils, 1987 Entry ID: NBId0211_101 |
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Summary
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Abstract:
The Africa Irrigation Potential data set, which represents the best soils suitable for upland, is part of the FAO Irrigation and Water Resources Potential Database. The main input maps were the 1977 FAO/UNESCO Soil Map of the Africa, UNESCO Geological World Atlas (scale 1:10 m), Mean Annual Rainfall map from hand drawn FAO/AGS climate maps, Template with water related features, Administrative Units map, and Watersheds map. All maps, apart from where specified were at a scale of 1:5 million, and all in Miller Oblated Stereographic projection. The soil suitability for irrigation was determined by evaluating the properties of all soil components: dominant soil, associations and inclusions, phases, slope, drainage, and texture. The classification was done for two major crop types: lowland crops (flooded rice), and upland crops (for all other irrigated crops except the lowland crops). The soils source includes a list of attributes for each soil unit including: slope, drainage, texture and phase (re: UNEP/FAO/ESRI ITU 100004). Then for both cases (lowland crops (flooded rice), and upland crops (for all other irrigated crops except the lowland crops)), two maps were generated. One with all soils which are suitable, and one where slope, texture, drainage and phase were considered. Each different soil type is classed according to suitability, S1 irrigation with no constraints, S2 irrigation with some constraints, N1 not suitable without major improvements, N2 permanently not suitable. Because one soil unit can consist of more soil components (unit Af26-a can mean 30%Bf and 70% Af) the suitability is expressed in percentage of the unit that is suitable (1 >50% suitable, 2 = 25-50% etc.). Then the soil characteristics are used to refine the ranking. This refining is done were the original soil rank is increased decreased or changed from their original suitability to a new suitability (so or soil gets new class S1, N1 etc. or ranking changes like, -1 lower soil rank by one, +1 raise soil rank with one). The Ranking of Soils is as follows The soils considered not suitable are: Lithosols, Arenosols, Rendzinas, Yermosols, Podzols, Thionic Fluvisols, Miscellaneous land units such as rock debris, desert debris, Gypsum units, Soils with stonic, lythic or petrogypsic phase. |
| N: 40.0 | S: -35.0 | E: 55.0 | W: -20.0 |
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Location Keywords
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CONTINENT
> AFRICA
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Science Keywords
| AGRICULTURE >AGRICULTURAL ENGINEERING [Definition] |
| AGRICULTURE >AGRICULTURAL PLANT SCIENCE >IRRIGATION [Definition] |
| AGRICULTURE >SOILS [Definition] |
| HUMAN DIMENSIONS >HABITAT CONVERSION/FRAGMENTATION >IRRIGATION >REGIONAL IRRIGATION [Definition] |
| LAND SURFACE >SOILS [Definition] |
ISO Topic Category
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FARMING
ENVIRONMENT GEOSCIENTIFIC INFORMATION |
Project
| GTOS >Global Terrestrial Observing System [Information] |
Access Constraints
| Public |
Keywords
| Agriculture > Agricultural Practices > Irrigation |
| Agriculture > Agricultural Practices > Irrigation Farming |
| CROPS |
| DRAINAGE |
| SLOPE |
| TEXTURE |
| Terrestrial Ecosystems > Soils |
Originating Center
| UNEP GRID - PAC |
Data Center
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Global Resource Information Database - Nairobi, Division of Early Warning and Assessment, United Nations Environment Programme
Data Center URL: http://gridnairobi.unep.org/
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Personnel
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JOHANNES
AKIWUMI Role: TECHNICAL CONTACT Phone: (+254-20) 7624214 Fax: (+254-20) 7624315 Email: Johannes.Akiwumi at unep.org Contact Address: Head, Data and Information Management Section Division of Early Warning and Assessment (DEWA) United Nations Environment Programme P. O. Box 30552 City: Nairobi Postal Code: 00100 Country: Kenya |
Creation and Review Dates
Last DIF Revision Date:
2012-05-31
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