Modeling the contributing factors of desertification and evaluating their relationships to the soil degradation process through geomatic techniques

Abstract

Desertification is a prolonged type of land degradation which converts the productive ecosystem to a fragile one by two crucial factors, namely, climate and negative human intrusion. The present study concentrates on identifying the causative factors of desertification, namely temperature, wind, rainfall scarcity and human pressure. It also concentrates on distinguishing the desertified land from degraded land and assessing the way in which the soil degradation process becomes accelerated by these factors, by employing data sets such as meteorological data and Landsat ETM+ (Enhanced Thematic Mapper) and OLI (Operational Land Imager) satellite images of the crop-growing period (June-October) in geostatistical methods and newly proposed remote sensing models, which yielded good accuracy with in situ observations (R2 = 0.8). The study was centered on two time periods, 2001-2011 (11 years) and 2012-2015 (4 years). In rainfall-temperature/drought-induced desertified region, the rate of salt-affected soils increased significantly from 12 to 58 % (2001-2015) due to the presence of native fluoride concentration and extreme temperature events. The region has also been experiencing high soil moisture stress (5 to 33 %) because of the insufficient occurrence of rainfall over a period of time. A longer term exacerbation of soil moisture stress (19 to 90 %) has been noted in the areas that were susceptible to wind-induced desertification, due to a high evaporation rate caused by extreme wind events for a substantial period. High human-induced soil salinity (36 %), human occupancy (16 %), followed by moisture stress (7 %) are observed in the human-affected region because of growing population and improper land management of the land that is already fragile.