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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 (JuneOctober) in geostatistical methods and newly proposed remote sensing models, which yielded good accuracy with in situ observations (R 2 = 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.

Soil moisture stress and salinity are considered as a major form of land degradation in rain‐fed agricultural regions. The study has been carried out for four distinct periods such as 2001, 2005, 2010, and 2015 that was selected according to the climatic variations that occurred more than a decade. The multispectral remote sensing‐based empirical models were employed on Enhanced Thematic Mapper Plus and Operational Land Imager imageries to estimate the rate of soil moisture stress and salinity from 2001–2015. The rate of soil moisture stress has been magnified to 143%, and salinity was increased by 70% particularly from 2005–2010 when the drought period occurred. The reliability of identifying the saline‐affected soils from the multispectral remote sensing models was significantly affected (R2 = 0.39) because of the extensive distribution of Nerium oleander plants and water logging state in the study region. The modified microwave water cloud model revealed the three‐layer information such as N. oleander, soil, and vegetation such that an imaginary part of the dielectric constant derived from simplified Hallikainen empirical model has got good correlation (R2 = 0.73) with ground electrical conductivity measurements. Copyright © 2016 John Wiley & Sons, Ltd.

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Abstract. Desertification is a prolonged stage of land degradation which converts the productive ecosystem to fragile by three crucial events namely evapotranspiration, rainfall and negative human intrusion. The present study concentrates on identifying the causative factors of desertification namely temperature, wind, rainfall and human pressure, distinguishing the desertified land from degraded land and assessing the way from which the soil degradation process gets accelerated by those factors by employing the datasets such as long term (2001–2011) and short term (2012–2015) Meteorological data and Landsat ETM+ and OLI satellite imageries of crop growing period (June–October) into geostatistical methods and newly proposed remote sensing models which yielded good accuracy with in situ observations (R2 = 0.8). In temperature induced desertified region, the rate of increment of the saline affected region was magnified significantly from 16 to 74 % (2001–2015) due to the presence of native fluoride concentration and extreme temperature event over a period of time. The long term exaggeration of soil moisture stress (19 to 90 %) has been notified in the areas that were susceptible to wind induced desertification, due to high evaporation rate invoked by extreme wind event for a substantial period. Similarly rainfall induced desertified regions have also been experiencing high soil moisture stress (4 to 70 %) because of the insufficient reception of rainfall. High human made 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 already fragile land.