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首页> 外文期刊>Science World Journal >SPATIO-TEMPORAL VARIATIONS OF TOP SOIL COARSENING AS A PEDO-GEOMORPHIC INDICATOR OF LAND DEGRADATION AND DESERTIFICATION STATUS IN A PART OF SEMI-ARID ZONE OF NIGERIA
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SPATIO-TEMPORAL VARIATIONS OF TOP SOIL COARSENING AS A PEDO-GEOMORPHIC INDICATOR OF LAND DEGRADATION AND DESERTIFICATION STATUS IN A PART OF SEMI-ARID ZONE OF NIGERIA

机译：尼日利亚半干旱地区部分土地退化和荒漠化状态的人为地貌指标：土壤粗化的时空变化

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Soil degradation is commonly mentioned as an indicator of desertification, not much is focused on specific form of soil degradation such as top soil coarsening which is rarely studied with respect to desertification. The major aim of this study therefore, is to assess the spatio-temporal patterns of top soil coarsening as a pedo-geomorphic indicator of desertification status (extent, rate and magnitude) in the semi-arid zone of Nigeria. This achieved using top soil grain size index (GSI) evaluated from remotely sensed reflectance of three (3) bands R, B and G of multi-temporal Landsat images (TM, 1987; ETM+, 2000 and OLI/TIR, 2015) and computed using a ratio algorithm. The multi-temporal sets of GSI (1987, 2000 and 2015) were generated from corresponding temporal Landsat images and? top soil grain size sensitivity index (GSSI) was evaluated from the sensitivity analysis of the geometric mean of the three sets of GSI. Each of the temporal GSIs and the GSSI were segmented into five (Very High, High, Moderate, Low and Very Low) sensitivity to desertification areas. Result show that there is a generalized temporal trend of increasing intensity of top soil fine sand content or coarsening and hence desertification in the study area. Although the intensity varies among all the respective sensitivity areas mapped. For instance the highest intensity of 21.15% was recorded in the Very High Sensitivity Area, followed by Moderate (18.39%), High (17.50%), Low (12.82%) and Very Low (7.53%). The spatial extents? of the distribution of? top soil coarsening or fine sand content show a decline in the Very High and High Sensitivity Areas at annual rates of 1.46 and 1.39 km2 respectively, while in the Moderate, Low and Very Low Sensitivity Areas expansion at annual rates 1.17, 1.38 and 1.38 Km2 respectively. Dynamic rate for the period (1987-2015) among sensitivity areas stood at Very High (3.56%), High (1.36%), Moderate (3.32%), Low (8.63%) and Very Low (43.74%). The single factor ANOVA analysis at 0.05 level of significance showed that there is significant variation in the change in top soil coarsening over the period (1987-2013) as well as among the various desertification sensitivity areas.
机译：人们通常提到土壤退化是荒漠化的一个指标，而很少关注特定形式的土壤退化，例如表层土壤粗化，这在荒漠化方面鲜有研究。因此，本研究的主要目的是评估尼日利亚半干旱地区表层土壤粗化的时空格局，作为荒漠化状况（程度，发生率和程度）的古迹地貌指标。使用多土壤Landsat影像的三（3）个波段R，B和G的遥感反射率（TM，1987; ETM +，2000和OLI / TIR，2015）进行评估并计算得出的最高土壤粒度指数（GSI）实现了这一目标使用比率算法。 GSI的多时相集（1987、2000和2015）是从相应的时空Landsat图像生成的？通过对三组GSI几何平均值的敏感性分析，评估了土壤最大粒径敏感性指数（GSSI）。每个时间GSI和GSSI被分为对荒漠化地区的五种敏感性（极高，极高，中等，极低和极低）。结果表明，研究区存在表层土壤细砂含量增加或粗化从而出现荒漠化的总体时间趋势。尽管强度在所映射的所有各个敏感区域之间变化。例如，在极高灵敏度区域记录了最高强度21.15％，其次是中度（18.39％），高（17.50％），低（12.82％）和极低（7.53％）。空间范围？的分布？最高土壤粗化度或细砂含量分别以每年1.46和1.39 km2的速度出现在极高和高敏感度区域的下降，而分别以每年1.17、1.38和1.38 Km2的速度出现中，低和极低敏感度区域的扩展。敏感区域期间（1987-2015年）的动态率分别为非常高（3.56％），高（1.36％），中度（3.32％），低（8.63％）和非常低（43.74％）。单因素方差分析的显着性水平为0.05，表明该时期（1987-2013年）以及各个荒漠化敏感性地区的表层土壤粗化变化存在显着变化。

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