The existence of vast areas covered with aeolian sand in many regions of Iran has made the use of this type of soil inevitable in engineering projects. Considering the abundance of fine-grained soil in Khuzestan plain along with the aeolian sand, it is important to investigate the effect of the addition of fine-grained soil to aeolian sand to improve its dry density and bearing capacity. In the present research, different percentages of fine-grained soil were added to aeolian sand from Khuzestan plain to determine its effect on the maximum dry density (gamma dmax), optimum water content (omega opt) and California bearing ratio (CBR) of the aeolian sand and fine-grained soil mixture. It was found that an increase in the percentage of fine-grained soil increased the gamma dmax and decreased the omega opt. The CBR of the soil increased under tests performed at the optimum water content and decreased under saturated conditions. The highest CBR for penetrations of 2.5 and 5 mm (CBR (2.5) and CBR (5)) when the samples were tested at an optimum water content was for the sample where the ratio of the dry weight of the fine-grained soil (WS(F)) to dry weight of the aeolian sand (WS(S)) is equal 40%. Comparison of the results of the current and previous research showed that, in areas such as the Khuzestan plain in which fine-grained soil is available, the use of such soil for improvement of aeolian sand is appropriate.

Sand dunes of the Quaternary age occupy large areas of Iran's semiarid and arid regions. In this study, some 33 sediment samples were collected from the crest, the lee and stoss sides of the linear dunes of the southern part of Qazvin plain. Sedimentological, geochemical, and mineralogical investigations were carried out in order to identify the origin and probable source of the aeolian dune sands. Grain size analysis of the sediments shows that most of the aeolian sands are generally fine-grained, moderately well-sorted, fine skewed and leptokurtic. The textural, mineralogical and the geochemical results supported by the statistical approach indicate that the dune sands were mainly derived from the Quaternary flood plain with a minor contribution from alluvial and fluvial sands. Facies study leads to the determination of 4 facies in 2 facies associations, including: 1) medium-grained lithofacies (Sdpc, Sdl, and Sdm), and 2) gypcrete facies (G). The studied aeolian sands are characterized by the predominance of gypsum and quartz, and stable minerals together with sedimentary, metamorphic, and volcanic fragments, and a few unstable pyroxene and amphibole minerals. The sand dunes of the Qazvin Plain record a semi-arid to arid paleoclimate and the relatively stable tectonic background characterized by the mineralogical and geochemical composition and gypcrete facies in the dunes.

Salt stress can negatively affect the development of seedlings. However, the use of alternative substrates can mitigate these effects. The present study aimed to evaluate the growth of yellow passion-fruit seedlings in response to irrigation with saline water grown on different substrates. The experiment was developed at the University of International Integration of AfroBrazilian Lusofonia, Redencao, Ceara, Brazil. The experimental design was entirely randomized, in a 2 x 5 factorial arrangement, composed of two levels of electrical conductivity of the irrigation water (0.3 and 3.0 dS m-1) and five substrate types (S1 = soil; S2 = sand, sandy soil, and bovine manure - 1:1:1; S3 = sand, sandy soil, and carbonized rice husk - 1:1:1; S4 = sand, sandy soil, and biochar - 1:1:1; S5 = sand, sandy soil, and vegetal ash - 1:1:1), with five replications. The S2 substrate containing sand, sandy soil, and bovine manure promoted higher performance of seedling height, stem diameter, shoot dry mass, root dry mass, and total dry mass associated with low salinity water. The S2 substrate was more efficient for leaf area, while S4 substrate was more efficient for number of leaves, root length, and pH. The S1 and S2 substrates presented higher electrical conductivity of the saturation extract using water of higher conductivity.

In order to increase the degree of food security in the areas affected by thermohydric stress in Romania, the aim is to identify new species of plants that can optimally exploit the microclimate of the area, through their biological potential. The pedoclimatic conditions recorded in the southern part of Romania offer an optimal microclimate for the growth and development of the sweet potato plant (Ipomoea batatas), which is a thermophilic plant, specific to tropical and subtropical areas. Research carried out between 2020-2022 on the sandy soils of southern Oltenia, showed that the sweet potato genotype s studied behaved differently in terms of tuber quality, accumulating a total amount of dry matter between 27% for the variety JUHWANGMI and 46.98% in the variety HAYANMI, with a variety average of 35.35%. Obtaining competitive productions is influenced by the choice of the most suitable sweet potato genotype for the area of sandy soils in S-W Oltenia. The average production for the three years of the study showed values between 17804 kg/ha for the DCh 19/3 genotype and 53368 kg/ha for the DK 19/1 genotype.

The gob-side entry retaining (GER) technique, as the family member of the pillarless coal mining system, is becoming popular, mainly attributed to its high resource recovery rate and significant environmental benefits. Seeking cost-effective backfill material to develop the roadside backfilling body (RBB) is generally a hot topic for coal operators and scholars. Except for its relatively high cost, the other shortcoming of the widely used high-water backfill material is also obvious when used in arid, semi-arid deserts or Gobi mining areas lacking water. The modified high-water backfill material (MBM) mixed with aeolian sand was recently developed as an alternative to conventional backfill materials. Some critical parameters affecting both the physical and mechanical properties of the MBM, including the amount of the aeolian sand and water-to-powder ratio of the high water-content material, have been experimentally investigated in the present research. Test results showed that the MBM featured high early strength and bearing capability after a large post-peak deformation. In particular, the adjustable setting time of the MBM through changing the amount of sand widens its application in practice. Unlike the high-water backfill material, the MBM is a typical elastoplastic material; the stress-strain curves consist of pore compression, elastic deformation, yielding, and total failure. Note that both the peak and residual strength of the MBM increased as the doping amount of aeolian sand increased, which is probably because of the impacted aeolian sand and the uniform reticular structure of the ettringite in the MBM. Compared with the high-water backfill material, only limited cementitious material and water resources are requested to cast the RBB, which provides more economical and environmental benefits for the application of the GER technique in the arid, semi-arid deserts or the Gobi mining areas.

Dry playa surfaces can be extremely vulnerable to disturbance which breaks their surface crusts resulting in increased aeolian sand and dust emissions. Trampling by livestock and motor vehicles is an important source of this disturbance. The Hamoun Lakes in the Sistan region of Iran are a major source area of dust storms which are causing damage to infrastructure and communities. This study performed portable wind tunnel tests of controlled surface disturbance by animals (cow, sheep) and motor vehicles (automobile, motorcycle) on a silty playa surface of Hamoun Saberi lake. The aim of this study was to assess the effect of different levels of trampling and disturbed surfaces by both vehicles and livestock on dust emission at wind speeds of 6 and 12 m s(-1). A significant increase of sediment emission was found with increased number of passes of vehicles and livestock and the degree of surface disturbance, more so at the high wind speed (12 m s(-1)). No significant differences were observed between a 10-20% disturbance level and an undisturbed surface, but statistically significant differences became apparent when disturbances reached 50-60% to 90-100% compared to undisturbed surfaces. Greater emission rates were reached by disturbances provided by automobile and cow compared to motorcycle and sheep, indicating greater trampling effects of automobile and cow likely related to greater weight and larger footprint. The automobile was the most surface-destructive of the four anthropogenic disturbances, providing emission in a lower number of passes compared to the motorcycle, cow and sheep. Better management of vehicle and livestock allocation on playas subject to disturbance, such as the Hamoun Lakes, will be a useful strategy to reduce disturbance and the frequency and intensity of dust storms.

Marginal sandy soils are frequently characterized by low fertility, low organic matter, moderate to high acidity and low cationic exchange capacity, limiting the options of smallholding farmers for various crops. To investigate the impact of the sowing time on grain yield, yield components, protein and oil content of peanuts cultivated in marginal sandy soils in Southern Oltenia, Romania, a bifactorial experiment in a randomized complete block design with three replications was conducted during 2015-2017 at the Research Development Station for Plant Culture on Sands Dabuleni. The first factor was sowing time (the 25th April as early sowing and the 5th May as late sowing) and the second factor was peanut cultivar (Dabuleni, Viorica, Viviana). According to the results of the experiment the sowing time had significant impact on the pods number per plant, the production of pods and the grain oil content. Analyzing the interaction between the sowing time and the cultivar there were significant differences only in the pod number per plant in 2015 and the production of pods in 2016. In all peanut's genotypes studied, early sowing led to higher yields of pods compared to late sowing, probably due to the shortening of the vegetation period of the crop by late sowing on the 5th May, which led also to less dry matter and lower oil content accumulated in peanut grains. Therefore, the results suggested that early sowing time is the most recommended for peanuts growth and quality yield in sandy marginal areas.

The diversity of soils and climate in Brazil imposes the need to evaluate the adaptation of fodder species to soil and climate conditions to guide producers and technicians in choosing the best alternatives for their region. The objective of this study was to evaluate and identify fodder cultivars for pasture and soil cover with tolerance to drought and high production in the sandy soils of southern Bahia, Brazil. The performance of 29 commercial cultivars of perennial and annual tropical forage species was evaluated in six cuts in 2019 and 2020. The green and dry mass yield per cut and the daily dry matter accumulation rate were evaluated considering the periods of water surplus and deficit and the drought tolerance index for each cultivar was estimated. Grass and legume cultivars showed differences in establishment, yield in the water surplus, and in the re-establishment after the water deficit. Based on the values of the drought tolerance index and in the dry mass daily yields before and after the water deficit, the cultivars adapted and indicated for regional continuous grazing were Xaraes, Marandu, Massai, Tanzania, Paiaguas, and Zuri, in that order. The grasses B. ruziziensis and B. decumbens were indicated for use as cover plants after the harvest due to their high capacity of establishment and short-term production. The annual and perennial legume plants were also indicated for cover, and the combination of cultivars and their potential for straw in direct planting or use in integrated systems still need to be validated.

Freeze-thaw cycles have a significant negative effect on the engineering behaviour of soil in cold regions. In this study, the compressive strength of stabilized, poorly graded sandy soil used in road pavement that was subjected to different freeze-thaw cycles was studied. Samples with three different particle shapes were stabilized with a binder developed by mixing polyvinyl acetate (PVAc) and ethylene glycol monobutyl ether (EGBE). The PVAc/EGBE weight ratio was 2:1, and PVAc was added at 1%, 2%, and 3% of the dry weight of the soil, with the effect of up to ten freeze-thaw cycles evaluated. Results showed that the addition of binder decreased optimum moisture content and increased compressive strength. An increase in particle roundness results in a decrease in the magnitude of compressive strength but increases the soil composite ductility. Changing particle shape from angular to rounded resulted in a more significant decrease in compressive strength than changing from rounded to well-rounded. The decrease in compressive strength is most significant between the first and fourth freezing-thawing cycles and marginal between the fourth and tenth. The negative effect of increasing the roundness of particles is compensated by increasing binder percentages.