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Soil fertility assessment and mapping for hot arid regions of Thar Desert in the Indian state of Rajasthan was carried out and on the basis of fertility ratings the soils were classified as low, medium and high. In the present assessment a systematic set of 5655 soil samples across the land use systems viz., rainfed croplands, irrigated croplands and rangelands covering 12 districts of hot arid Rajasthan were collected using global positioning system (GPS). The soil samples were analyzed for pH, electrical conductivity (EC), organic carbon (OC), available phosphorus (P), potassium (K), iron (Fe), zinc (Zn), copper (Cu) and manganese (Mn). Results of the soil analysis revealed that OC is low throughout the region, while available P was low to medium, but generally medium to high in available K. Among the micronutrients, Cu and Mn were adequately supplied in most areas, but Zn and Fe were inadequate in large parts. The spatial variability of OC and available plant nutrients viz., P, K, Fe, Zn, Cu and Mn in hot arid regions of Rajasthan across the land uses in region, has been mapped in a geographic information system (GIS), and their adequacy determined as per the criteria followed in the soil testing laboratories. Spatial distribution maps indicated that about 99.4, 48.7, 11.0, 56.1 and 41.0% of the area are under low availability class for OC, P, K, Zn and Fe, respectively. Present study also showed that the hot arid regions of India not only deficient in individual nutrients but they also suffer from multi-nutrients deficiencies which warrants attention for soil test based integrated plant nutrition system. The wide spread deficiencies of P, Fe and Zn were most revealing; their deficiencies varies with topography, soil type and land management practices. Irrigated croplands were better endowed than other land uses in respect of OC, P, Zn and Cu; rangelands in respect of K and Fe, and rainfed croplands in respect of Mn. With use of information technology tools like GIS and GPS helps in generation of spatial data/maps on distribution of available plant nutrients with which we can precisely use the required input at right place (location specific application of inputs). Information on spatial distribution of available micronutrients enables grouping of the soils into homogenous units for better nutrient management.

In the arid region of Rajasthan, India, it is very often a challenge to store rain/surface water for year-round use by human and livestock. The inhabitants of this desert area have developed several water storage structures, which they used to construct based on their indigenous knowledge of local terrain conditions. Recently, farmers living in the lower command areas of Indira Gandhi canal have constructed micro-farm water storage structures, called diggi, in their cropland. They store allocated canal water in diggi to timely utilize it as per irrigation requirements, and thus, done away with problems of deficit and untimely canal water supply. This impact assessment study, carried out in Poogal tehsil of Bikaner district, analyzed high-resolution satellite images of two years and used geographic information system to quantify diggi structures and studied the diggi-growth interactions with changing rainfall pattern as well as land use/land cover. Results showed that during 2018, about 3243 number of structures were constructed compared to 241 existed during 2004-05. The mean annual rainfall increased by 30% and crop area by 12772 ha during the same period that included 7.86% increase in irrigated and 2.98% in rainfed croplands. Thus, diggi based water management has been immensely helpful in the perspective of irrigated agriculture in the desert region.

This study developed a novel framework for integrating time series modeling with geographic information system (GIS). For the first time, procedures of four statistical tests, i.e., t-test ...

Knowledge of rainfall variability is important for regional-scale planning and management of water resources in agriculture. This study explores spatio-temporal variations, trends, and homogeneity in monthly, seasonal, and annual rainfall series of 62 stations located in arid region of Rajasthan, India using 55 year (1957–2011) data. Box-whisker plots indicate presence of outliers and extremes in annual rainfall, which made the distribution of annual rainfall right-skewed. Mean and coefficient of variation (CV) of rainfall reveals a high inter-annual variability (CV > 200%) in the western portion where the mean annual rainfall is very low. A general gradient of the mean monthly, seasonal, and annual rainfall is visible from northwest to southeast direction, which is orthogonal to the gradient of CV. The Sen’s innovative trend test is found over-sensitive in evaluating statistical significance of the rainfall trends, while the Mann-Kendall test identifies significantly increasing rainfall trends in June and September. Rainfall in July shows prominently decreasing trends although none of them are found statistically significant. Monsoon and annual rainfall show significantly increasing trends at only four stations. The magnitude of trends indicates that the rainfall is increasing at a mean rate of 1.11, 2.85, and 2.89 mm year−1 in August, monsoon season, and annual series. The rainfall is found homogeneous over most of the area except for few stations situated in the eastern and northwest portions where significantly increasing trends are observed. Findings of this study indicate that there are few increasing trends in rainfall of this Indian arid region.

Soil plays a critical role in earth’s biosphere by supporting the production of food, fodder and fiber. However, rapid land use changes in recent times in different parts of the world led to increasing concern on soil health. It has been realized that changes in land use systems significantly affect soil properties. Therefore, we studied the impact of land use systems on soil physicochemical properties in the Thar Desert of India. Surface soil samples (0–30 cm) from four land use systems: (1) sand dunes, (2) grazing lands, (3) rainfed croplands and (4) irrigated croplands have been collected and analyzed in laboratory to determine soil pH, electrical conductivity (EC), CaCO3 content, organic carbon content, available P content, available K content and micronutrients (Zn, Fe, Mn, and Cu) content. We observed higher clay, organic carbon and nutrient contents and lower bulk density values in irrigated croplands than in other land use systems. Soil pH and EC were higher in irrigated croplands than in the other land use systems. Principal component analysis of soil physicochemical properties revealed two major soil factors, the clay–carbon factor and salinity factor, which were able to significantly differentiate the land use systems. For irrigated croplands, the clay–carbon factor was found to be higher than the rest of the land uses; however, the salinity factor was the lowest. Higher values of these two factors will lead to a favorable soil physicochemical environment for plant growth or better soil health. These two factors may further be used for assessing the impact of land use systems on soil quality in other regions.

Wind erosion is a severe land degradation process in hot arid western India and affects the agricultural production system. It affects crop yield directly by damaging the crops through abrasion, burial, dust deposition etc. and indirectly by reducing soil fertility. In this study, an attempt was made to quantify the indirect impact of wind erosion process on crop production loss and associated economic loss in hot arid ecosystem of India. It has been observed that soil loss due to wind erosion varies from minimum 1.3 t ha −1 to maximum 83.3 t ha −1 as per the severity. Yield loss due to wind erosion was found maximum for groundnut ( Arachis hypogea ) (5–331 kg ha −1 yr −1 ), whereas minimum for moth bean ( Vigna aconitifolia ) (1–93 kg ha −1 yr −1 ). For pearl millet ( Pennisetum glaucum ), which covers a major portion of arable lands in western Rajasthan, the yield loss was found 3–195 kg ha −1 yr −1 . Economic loss was found higher for groundnut and clusterbean ( Cyamopsis tetragonoloba ) than rest crops, which are about 191–12465 ha −1 depending on the severity of wind erosion. For mustard ( Brassica spp.) and wheat ( Triticum spp.) the economic loss was about 47–3181 ha −1 , whereas for pearl millet the economic loss was lowest ( 36–2294 ha −1 ). In this calculation only indirect impact of wind erosion in terms of reduction in soil fertility was considered. There is need of future research work for assessing the direct damage on crops by wind erosion process, addition of which may lead to higher magnitude of losses.

The present study is an attempt to assess the spatial variability and the changes in the population of Prosopis cineraia (khejri) trees in the agroforestry systems of arid part of western Rajasthan. This tree is regarded as an important natural resource for the rural livelihood of desert dwellers because of its multifarious uses. The tree populations were mapped in a geographical information system using available information from aerial photographs, google earth images and IRS-LISS-III satellite images to compare their populations between the past and the very recent period. Mapping carried out in a part of Nagaur district in western part of Rajasthan, indicated increase in khejri trees in the region in 2013–2014 compared to 1960s. The number and tree density were higher under irrigated croplands than under rainfed. Increase in rainfall, multiple uses of the tree, societal and scientific support are the key reasons for the observed changes in their population.

Understanding the spatial variability in soil parameters is important for efficient management of soil resources. The present study evaluated the influence of landform on the spatial variability of chemical and physical attributes of soils of Central State Farm, Jetsar, Sri Ganganagar district, Rajasthan. The highest available macro and micronutrients content were observed in soils of aeo-fluvial plain followed by stabilized sand dune and active sand dune. The soils across the landforms were low in organic carbon content barring 3 per cent soil samples of aeo-fluvial plain. The mean available N was 153, 139 and 112 kg ha-1 in aeo-fluvial plain, stabilized sand dune and active sand dune, respectively. The available P in stabilized sand dune and aeo-fluvial plain was found high whereas it was medium in active sand dune. About 41, 22 and 17 per cent soil samples of aeo-fluvial plain, stabilized and active sand dunes were high in available K, respectively.

A vast area between Phalodi in Jodhpur and Pokaran in Jaisalmer district of western Rajasthan, is occupied distinctly by rocky, shallow gravelly surfaces and occasional hills. These surfaces exhibit quartz and quartzite pebbles, angular, sub-angular and few rounded sandstone gravels, have slightly convex outline and can be best described as desert pavements. Such land features assume significance because of their extent and variability under a dominantly dry aeolian environment. Morphology and distributional pattern of such formations indicate that sediments are either of in situ origin or may have been transported to a short distance. The present study is based on field level assessment of such surfaces in the above two desert districts. Over much of the area, the profile shows a surficial concentration of gravels followed by thick sand and silt mixed with gravels and then the parent material. There are also occasional rock outcrops of very low relief exhibiting vertical, horizontal and conchoidal pattern of fractures over these surfaces near Pokaran and north of Jaisalmer which indicate disintegration of rocks under extreme diurnal fluctuation of temperature. Such manifestations in the morphology indicate impact of both thermal as well as aeolian processes. In the east of Jaisalmer town near Basanpir and Bhojka, the pavement surfaces are found covered with abundant sub-rounded to rounded pebbles and cobbles. This type of condition would indicate a profound action by fluvial activities followed by wind sorting. Our study found significant spatial variability in the distribution of pavement surfaces, which carried imprints of climatic fluctuations and environment of deposition during Holocene.

The article made an inventory of typical frost heave features in the cold arid region of the Leh-Ladakh region. The study found variations in morphology and patterns and also identified degraded forms of heaves. Such features were correlated with pasture degradation in the region.

In early and mid-twentieth century, there were speculations and apprehension that the Thar Desert is spreading towards east and it may cover large fertile areas of present day Punjab, Haryana, west Uttar Pradesh and east Rajasthan. Therefore, the Government of India established a Desert Afforestation Research Station at Jodhpur, Rajasthan in 1952 mainly to focus on sand dune stabilization and shelterbelt plantations to reduce wind erosion. In 1957, it was reorganized as Desert Afforestation and Soil Conservation Station. Just after two years (in 1959), it was restructured as the Central Arid Zone Research Institute (CAZRI).

A quantitative study on fluvial processes was carried out in an upland stream catchment (9.3 ha) near Agolai in the NE of Jodhpur district in the Thar Desert in Rajasthan. The catchment of the studied second order ephemeral channel (1.0 - 1.4 km long and 1.0 - 1.5 m deep) has developed on a hill - rocky/gravelly pediment - colluvial plain sequence on rhyolite. Initial results of measurements of channel parameters during two significant runoff generating events of 42 mm and 52 mm in 2007 showed peak discharges of 20 m 3 s -1 (upstream) and 13 m 3 s -1 (downstream) that moved sediments (bedload) to distances of 43 m - 141 m in the upstream reach, 6-28 m in the middle reach and 63-95 m in the lower reach. The long profile and cross profile measurements showed a balance between load and discharge through a sequence of alternate deposition and erosion throughout the channel. Hypsometry curves revealed maximum erosion (7.7 cm) in the upper reach and aggradation (2.90 cm) in the lower reach. Cross profile measurements showed bank cuts (6 cm) and vertical incisions (1-2 cm) on the rocky-gravelly V shaped valley in the upper reach, incision (4- 30 cm) and localized higher deposition (10-12 cm) in the narrow ( 1m) U shaped valleys in middle reach and mainly deposition (13 cm) on the wide (1-4 m) and shallow channels (0.1 to 0.2 m) in the lower reach.

In arid regions, inherent climatic conditions and adverse terrain condition pose perpetual shortage of water. The dominant aeolian topography conceals older geological formations making it difficult to infer prospects of ground water and tapping the same. A ground water prospect map has been prepared for a part of Jodhpur district in western Rajasthan through integrated analysis of four major controlling factors: geology, geomorphology, structure and hydrology. Through visual interpretation of satellite data and using Geographical Information System, twenty-five hydro-geomorphic units (prospect units) have been delineated and mapped. Potential of each prospect unit have been discussed in reference to hydro-geomorphic units, their influence and well inventory like well yield, water table level and quality of drinking water. 34 % of the area was classified to have high groundwater potential and 5.8 % area was classified into low potential categories. Most of the area (60.2 %) is of moderate ground water potential.

The sandy landscape in a desert contains very few stream channels. This poses a problem for delineating watersheds for analysis. Since large-scale topographical sheets of sandy terrain also contain very little information on height, delineation of watersheds from topographical sheets often becomes difficult. In order to find a simple solution to the problem in the Thar desert of Rajasthan, India, the authors used the well-known ARC/INFO software for simulation of height and drainage network using the scarce topographical information for a sandy terrain near Jodhpur. Superimposition of data layers generated from remote sensing and secondary sources validated the simulation results, and suggested suitability of the method for application in similarly handicapped areas.

Land resource development programmes are applied generally on a watershed basis. Delineation of watersheds within a large drainage basin and their prioritization is required for proper planning and management of natural resources for sustainable crop production. An integral part of Guhiya basin (with an area of 1614 km2) was studied for priority watershed delineation with the objective of selecting watersheds to under take soil and water conservation measures using remote sensing and Geographical Information System (GIS) techniques. Using the terrain information derived from geocoded satellite data and 1:50,000 topographic maps, 68 watersheds were assessed on the basis of their erosivity and sediment-yield index values. Thematic maps of landform, land-use and land-cover, and slope were digitised using ARC/INFO. On the basis of sediment yield index values the watersheds were grouped into very high, high, moderate and low priorities. High priority watersheds with very high SYI value (>150) need immediate attention for soil and water conservation whereas, low priority watershed having good vegetative cover and low SYI value (