Plant growth is often constrained by low availability of water and phosphorus (P) in soils in arid and semi-arid areas. Aeolian sandy soils cover >90% of the sandy area of the Mu Us Sandy Land (MUSL) in Northwest China. These soils have low water- and nutrient-retention capacity, limiting their ability to support plant growth. Pisha sandstone, a type of loose rock widely distributed in the MUSL, is regarded as an environmental hazard because it easily weathers, resulting in severe soil erosion and water loss. However, the retention capacity of the aeolian sandy soil can be significantly improved through blending with Pisha sandstone. We investigated the impacts of water supply (35% and 70% of soil water-holding capacity) and P supply (0, 5 and 20 mg P kg(-1) soil) on plant growth and P and nitrogen (N) nutrition by growing lucerne (Medicago saliva L.) in MUSL aeolian sandy soil amended or not with Pisha sandstone. Soil type and P supply had greater effects than water supply on lucerne growth and on P and N nutrition. Biomass accumulation and shoot P and N concentrations were increased by amending the aeolian sandy soil with Pisha sandstone and increasing P supply. The N : P ratios in shoots indicated that plant growth was limited by P but not by N. Aeolian sandy soil amended with Pisha sandstone and supplied with P at 5 mg kg -I enhanced lucerne growth; this practice is feasible for pasture development in the MUSL.

The Tolmount Field is a lean gas condensate accumulation located in Block 42/28d of the UK Southern North Sea. The field was discovered in 2011 by well 42/28d-12, which encountered good-quality gas-bearing reservoir sandstones of the Permian Leman Sandstone Formation. The discovery was appraised in 2013 by wells 42/28d-13 and 42/28d-13Z, which logged the gas-water contact on the eastern flank of the field. The Tolmount structure is a four-way, dip-closed, faulted anticline, orientated NW to SE. The reservoir comprises mixed aeolian dune and fluvial sheetflood facies deposited within an arid continental basin. Dune sands display the best reservoir properties with porosities around 22% and permeabilities exceeding 100 mD. Only minor diagenetic alteration has occurred, primarily in the form of grain-coating illite. Superior reservoir quality is observed at Tolmount compared to adjacent areas, due to the preservation of dune facies, a hypothesized early gas emplacement and a relatively benign burial history. Current mapped gas initially-in-place estimates for the field are between 450 bcf and 800 bcf, with an estimated recovery factor between 70 and 90%. An initial four-well development is planned, with first gas expected in 2020.

Multi-proxy analyses of a sequence spanning the Younger Dryas (YD) in the Glacial Lake Hind basin of Manitoba provides insight into regional paleohydrology and paleovegetation of meltwater rivers and lakes spanning >4000 yr; the sequence is controlled by 25 new accelerator mass spectrometry ages. This lake, dammed by the Laurentide Ice Sheet, overflowed into Lake Agassiz. The pre-YD interval records rapid sedimentation from meltwaters that headed in proglacial lakes in the Canadian Prairies that are known to have been catastrophically released when ice or sediment barriers were breached. Pollen in this phase is dominated by pre-Quaternary forms eroded from Paleocene bedrock. At the onset of the YD at similar to 12.8 cal ka, the sudden appearance of concentrations of nanodiamonds, high-temperature magnetic spherules, platinum, and iridium provide evidence of an extraterrestrial (ET) event that others have identified at more than 40 sites in North America. Major changes in oceans and climate, and the catastrophic outflow of nearby Lake Agassiz at the onset of the YD, may be related. Lower water levels and a reduction of Souris River inflow to Lake Hind followed, which are reflected by more clayey and organic-rich sediments and a decrease in pre-Quaternary palynomorphs. This may have resulted from the deepening of river valleys caused by the release of meltwater triggered by the ET event. Wetlands then began to develop, leading to peat deposition from 12.3 to 11 cal ka. This was followed by a fluvial episode depositing sand and then by increased Holocene aridity that resulted in accumulation of a thick sequence of dune sands. A dry woodland environment with a mix of conifers (especially Picea and Larix) and deciduous trees (especially Populus and Quercus) covered the uplands from similar to 13 to 10 cal ka.

The Crescent Moon Spring is a unique scenic spot located in an aeolian sand environment of northwestern China. The water level of this spring has continuously declined in recent decades, causing both the government and many scholars great concern. To better understand its hydrologic structure, this study investigated the origin of the spring and its recharge sources based on the hydrochemical and isotopic (O-1(8), H-2 and H-3) composition of 56 water samples collected along the groundwater flow path. The results indicate the spring is a window into the groundwater table cut out of low-lying terrain in sand dunes, with the geographic and sedimentary conditions affecting its genesis and hydrochemistry. The spring and shallow sedimentary aquifers are recharged primarily by river water, while deep bedrock aquifers are recharged by deep lateral groundwater flow via fault zones in the piedmont of the Qilian Mountains. The results of recharge altitude calculations demonstrate a possible groundwater supply from deep bedrock aquifers to the south of spring. The recorded environmental H-3 content varied from 11 to 40 T.U., indicating the groundwater is primarily recharged by glacier meltwater from modern precipitation, with only a small fraction from pre-modern times. End-member analysis using Cl- and delta O-1(8) shows recharge ratios of influent water from the Dang River and deep groundwater represent about 43 and 22% of the lake water, respectively, with artificial recharge accounting for the remaining 35%. Regional hydrogeological conditions, arid climate, and sand deposition have negative influences on the maintenance of lake water levels, but observed regional groundwater level declines resulting from the construction of the Dang River Reservoir, seepage from drainage canals, and excessive exploitation of groundwater are the most important factors contributing to the ecological crisis in the study area. These results provide insights into the origin and recharge sources of the Crescent Moon Spring that will guide efforts to preserve the water level.

The main objective of this study is to enhance the performances of local materials in order to be used in road construction sector. To enhance the performances of this local materials, the strategy adopted is to combine the beneficial effects of mixing different materials and treatment using binders. The materials used in this study are tuffs and dune sands. Hence the present work is also a contribution to the co-valorisation of local materials in arid region of the south of Algeria. According to the results obtained, it is shown that the tuffs of the Saharan regions are suitable for the use of Saharan pavements, particularly in base layers and foundations. The incorporation of dune sand up to 20% improves the mechanical performance. The binders treatment (cement, lime and cement/lime) have induced a further improvement in bearing capacity and compressive strength as well as tensile strength. With these improvement, the materials could be used in roads with heavy and important traffic.

Pleistocene loess of the Rhone Valley and Provence region, disconnected from the two main European aeolian systems (North European Loess Belt and Danube basin), are of interest to test the impact of source variability, grain size sorting, weathering and sediment recycling on the geochemical composition. The concentration of major, trace and rare earth elements in loess and potential sources was analysed through Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) and ICP-Mass Spectometry (ICP-MS). Analyses show a genetic relationship between loess and the Ca-rich river sediments from the Alpine Ice Sheet (AIS). The loess of Provence show distinctive properties with a higher CaO and MgO content and a higher Europium anomaly (Eu/Eu*), suggesting sources richer in dolomite together with a contribution from mafic rocks (Alpine ophiolite complex). The homogeneous loess composition, compared to alluvial sources, reflects particle mixing during transport in the atmosphere. At the European scale, the geochemical composition of loess changes according to regions, but remains consistent within each region. Such variability is mostly related to the composition of rocks outcropping in respective catchments and especially in areas covered by ice sheets. The Chemical Proxy of Alteration (CPA) and Rb/K ratio suggest a weak chemical weathering linked to the cold and dry conditions typical of the Last Glacial. Recycling of older aeolian formations possibly caused loess enrichment in resistant minerals and quartz, especially for loess derived mostly from the abrasion of aeolian sand (Aquitaine).

This study investigated the water balance physiology of Venezillo arizonicus, a land isopod endemic to the Southwest Desert Ecoregion of North America. Evaporative water losses were measured in two ways: gravimetric in dry air, and by perfusing animals with dry air in a respirometry chamber and monitoring downstream relative humidity (RH). The respective mean loss flux estimates were 0.140 and 0.177 mu g h(-1) cm(-2) Pa-1, lower than other N. American Oniscidea described to date (>= 0.491 mu g h(-1) cm(-2) Pa-1). Humidity monitoring revealed intermittent sharp peaks in RH, attributed to the release of maxillary urine. Whole-animal flux increased as a function of temperature, with a critical temperature (T-c) between 38 and 42 degrees C identifiable by a clear Arrhenius break point. Hexane-rinsed whole animals yielded straight-chain, saturated hydrocarbons (C-21-C-33). The surface density of extracted alkanes (0.64 mu g cm(-2)) was somewhat higher than previously determined values for mesic species, although modest compared to insects and arachnids. Dehydrated animals exposed to high RH (> 88%) demonstrated active water vapor absorption (WVA) like other Crinocheta, with an extrapolated uptake threshold of approximately 85% RH (A(w) = 0.85), the lowest value reported for Oniscidea. The maximum uptake flux increased linearly as a function of ambient RH. Mass-specific uptake in 100% RH was 49% d(-1), similar to values determined previously for Armadillidium vulgare and Porcellio scaber. The low WVA threshold of V. arizonicus, and the species low permeability, are consistent with its known range in the arid desert southwest and the desiccation stress of its typical aeolian sand and seasonal wash habitats.

Seasonal flooding following heavy rain deposits large amounts of sediments on productive lands in the lower parts of fields in western Tennessee. The deposited sediments have high proportion of sand particles that negatively affect soil physiochemical properties, which make the soil uneconomic for farming. Soil amendments such as biochar, a by-product of renewable energy production from organic waste materials, have the potential to remediate sandy soil left after flood events and improve crop yields by increasing water holding capacity and soil nutrient content. The objective of this project was to evaluate the effect of biochar produced from two types of hardwood feedstocks on water retention and corn (Zea mays L.) growth in sandy soil. A greenhouse experiment quantifying the growth of corn was conducted in a randomized complete block design with five replications. Sandy soil was amended with three biochar rates (0, 10, and 20% by volume) under two irrigation levels. The irrigation levels were control and a dry treatment based on the past 10 yr of rainfall data. Biochar application greatly improved water retention in the flooded sandy soil. Biochar increased soil K and P concentration. However, at the end of the study, corn growth was not different in biochar amended and non-amended sandy soil. This research demonstrated that biochar as a soil amendment has the potential to improve quality attributes of poor soil, such as the soil water and nutrient concentration in a previously flooded sandy soils.

Sandy soils make up a substantial fraction of cropping land in low rainfall (<450 mm p.a.) south and south-eastern Australia. In this paper we review the possible soil constraints to increased production on these soils in this region. Many of these soils have a very low (<3%) clay content and suffer from severe water repellency, making crop establishment and weed control problematic. Crops which do emerge are faced with uneven soil wetting and poor access to nutrients, with crop nutrition constraints exacerbated by low fertility (soil organic matter < 1%) and low cation exchange capacity. Zones of high penetration resistance appear common and have multiple causes (natural settling, cementation and traffic induced) which restrict root growth to <40 cm. Crop water use and grain yield are therefore likely to be well below the water-limited potential. Water repellency is readily diagnosed and where apparent should be the primary management target. Repellency can be mitigated through the use of furrow and other sowing technologies, along with soil wetting agents. These techniques appear to be affected by site and soil nuances and need to be refined for local soils and conditions. Once crop establishment on water repellent soils has been optimised, attention could be turned to opportunities for improving crop rooting depth through the use of deep tillage or deep ripping techniques. The required ripping depth, and how long the effects may last, are unclear and need further research, as do the most effective and efficient machinery requirements to achieve sustained deeper root growth. Crop nutrition matched to the water-limited crop yield potential is the third pillar of crop production that needs to be addressed. Low soil organic matter, low cation exchange capacity, low biological activity and limited nutrient cycling perhaps make this a greater challenge than in higher rainfall regions with finer textured soils. Interactions between nutrients in soils and fertilisers are likely to occur and make nutrient management more difficult. While amelioration (elimination) of water repellency is possible through the addition of clay to the soil surface, the opportunities for this may be restricted to the similar to 30% of the sandy soils of the region where clay is readily at hand. The amounts of clay required to eliminate repellency (similar to 5%) are insufficient to significantly improve soil fertility or soil water holding capacity. More revolutionary soil amelioration treatments, involving additions and incorporation of clay and organic matter to soils offer the possibility of a more elevated crop yield plateau. Considerable research would be required to provide predictive capacity with respect to where and when these practices are effective.

Slope failures caused by rainfall are common occurrences in many parts of the world and are severe in Japan where there are significant numbers of slopes susceptible to failure. To understand the mechanisms and conditions leading to such failures, constant shear stress tests that mimic the field stress path were conducted on a sandy soil taken from a natural sliding slope whose surface soils were moving. Water was infiltrated from the bottom and top of an initially unsaturated cuboid soil specimen at constant shear stress until failure. The effects of cyclic wetting and drying on the deformation characteristics and four parameters reflecting the initial conditions, i.e., the dry density, overburden pressure, rainfall intensity, and slope angle, as well as various parameter combinations, on the time and moisture content allowing for failure initiation were investigated. The experimental results exhibited a unique relationship between the deformation and moisture content and suggested a relationship for predicting the time and moisture content of onsets of landslides based on the four parameters. The results obtained can serve as guidelines for the design of landslide hazard detection systems and mitigation measures against rainfall. (C) 2019 Elsevier Ltd. All rights reserved.