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Soil acidification is a major problem in the inland Pacific Northwest. A potential solution is the application of lime to neutralize acidity and raise pH. As lime is an expensive input, precision variable rate application is necessary. However, high-resolution mapping of pH and buffer pH for lime prescription requires costly sampling and analysis....
Citations
... The semi-arid region of Cameroon, fragile ecological zone with poor vegetation cover, highlights some characteristics facilitating the use of Remote Sensing data than in the rainforest where there is no direct relationship between soil and wavelength due to canopy cover. Remote Sensing methods are useful for soil survey, soil suitability mapping, soil erosion and conservation, determination of soil mineralogical composition, soil texture, soil moisture, soil organic matter, soil salinity [1,10,11,12,13] [14,15,16,17,18,19,20,21]. Such modern methods can also help to delineate soil units, deduce soil properties, facilitates digital soil mapping, facilitate access to inaccessible areas, reduce the time and cost compared for conventional soil map [6,22] and provide a synoptic view of the area [23,24,25,26,27,28].Therefore, there exists Radar and optical Remote Sensing systems, airborne and space-borne, with greater area coverage and coarse resolution, to provide soil data at regional scale, while LIDAR, ground-based, monitors with finer resolution [1,7,8]. ...
Remote Sensing and Geographic Information System methods used to map soils over space and time have numerous advantages over conventional soil mapping techniques which are time consuming, labour intensive, expensive and cover limited areas. In Cameroon, most soil maps were established at small scale using conventional methods and soils units are poorly delineated making it difficult to properly manage soils for various purposes. This study aims to use spectral signatures and GIS techniques to update existing soil maps. The method is based on
ETM+ image processing, field investigation and existing data from other maps to update an existing soil map of the Mayo Kani Division in Far North Cameroon. The methodology consisted of interpreting the relationship (colour, organic matter, iron content, texture, moisture content, vegetation, human activities) between soil and satellite images. The main results revealed that delineation of soil units using GIS permitted to establish a soil map and to update soil digital data. Thus, percentages of Vertisols, Ferruginous soils and Halomorphic soils decreased from
38.38, 26.87 and 10.64 to 36.88, 25.67 and 9.13 respectively. Meanwhile, the percentages of less evolved soils, Raw Mineral soils and Hydromorphic soils increased respectively from 14.17 to 16.17, 0.43 to 0.54 and 8.73 to 10.67, while percentage of fersiallitic soils remained constant, at 0.73. These results reveal that Remote Sensing data and GIS constitute a valuable approach to update existing soil map and to draw digital soil maps. It is recommended that Remote Sensing data be combined with field data to obtain more precise maps.
