Aeolian sand serves as the primary filling material for highway and railway in the desert area of Inner Mongolia, China. Usually, aeolian sand subgrade is stable in the natural state. Nevertheless, the infiltration caused by rainfall events disrupts the original balance within the subgrade. The hydraulic properties of aeolian sand subgrade change substantially in a short period, which results in a decrease in shear strength and subsequent deformation or landslide of the subgrade. Based on the analysis of soil properties and structural characteristics of aeolian sand subgrade, a prediction model for rainfall infiltration depth considering soil properties and rainfall levels of aeolian sand subgrade was proposed based on the linear approach of soil water characteristic curves (SWCCs). This study further used the aforementioned prediction model to predict the infiltration depth of aeolian sand with three different dry densities under an extreme rainfall event and compared it with numerical simulation results to verify the applicability of the prediction model. This study can provide a theoretical basis for the study of the hydraulic behavior of aeolian sand subgrade soil.

Introduction. Low-fertility soils and high logistics costs for seedling production characterize the Peruvian Amazon. Objective. To evaluate the effect of a combination of sandy soil and oil palm compost on substrate, growth, and nutrition of cocoa seedlings under greenhouse conditions. Materials and methods. The experiment was conducted for 90 days in Yurimaguas, Loreto, using a completely randomized design in a 5 x 5 matrix, with five doses of oil palm compost and sandy soil to determine the best combination for cocoa growth and nutrition. Height (cm), diameter (mm), leaf area (cm2), dry weight of stem and root were measured; soil chemical analysis and plant analysis (macro and micronutrients) were also conducted. Results. Sandy soil showed no significant effect on cocoa seedlings, while treatments with oil palm compost promoted shoot and root biomass. Additionally, this compost favored conditions for seedling growth by promoting higher organic matter, available phosphorus, exchangeable calcium, potassium, and higher cation exchange capacity. Regarding cocoa nutrition, it promoted greater absorption of macro and micronutrients in seedlings. Conclusions. These results indicate that the best treatment was the one composed entirely of oil palm compost, as it promotes growth and nutrition by improving substrate conditions.

The vegetation pattern generated by aeolian sand movements is a typical type of vegetation patterns in arid and semi-arid areas. This paper presents a vegetation-sand model with nonlocal interaction characterized by an integral term with a kernel function. The instability of the Turing pattern was analyzed and the conditions of stable pattern occurrence were obtained. At the same time, the multiple scales method was applied to obtain the amplitude equations at the critical value of Turing bifurcation. The spatial distributions of vegetation under different delays were obtained by numerical simulation. The results revealed that the vegetation biomass increased as the interaction intensity decreased or as the nonlocal interaction distance increased. We demonstrated that the nonlocal interaction between vegetation and sand is a crucial mechanism for forming vegetation patterns, which provides a theoretical basis for preserving and restoring vegetation.

Parabolic dunes form and migrate in almost every climate and geographic zones of the world, ranging from the tropical coastlines to the arid continental deserts. Despite their extensive distribution and their importance within the aeolian sediment landscape, the understanding of their morphological development, activity and link with climates remains somewhat limited to local or regional scales. A good understanding of the present climate conditions under which parabolic dunes are formed and/or reactivated would be significantly helpful to constrain past climate models. Similarly, an improved knowledge of parabolic dunes behaviour during past climatic episodes would provide some valuable long-term data to better predict their future activity. This review first aims at providing a non-exhaustive global database on parabolic dune morphology and the present wind regimes with which they are associated. To do so, the morphology of 750 dunes distributed worldwide was first analysed using a high-resolution global digital elevation model, suggesting an intrinsic relationship between the different measured morphoparameters. The analysis of the associated local wind regimes shows that parabolic dunes develop under strong unidirectional winds, which are more conspicuous in coastal than continental environments. Dunes of different ages are globally aligned with present prevailing winds, which suggests a prevalent control of long-term global atmospheric circulation on dune orientations. Finally, this study explores the link between parabolic dune activity and climates over the past 20 000 years by reviewing ages from the literature and combining them with the ones compiled in the INQUA Dunes Atlas Chronologic Database. Overall, it appears that changes towards drier conditions have triggered dunes migration during both warm and cold periods of the Last Glacial Maximum, Holocene Climate Optimum, Roman Climate Optimum, Medieval Climate Optimum and Little Ice Age. The present day aeolian activity is predominantly linked with deteriorating environmental conditions caused by human disturbances.

Sand dunes are one of the most common soil types all over the world, particularly in North Africa and the Arabian Peninsula. These dunes, with their regional extensions, are considered the main natural resource for fine aggregates being used in construction purposes. To use dune sands as a road construction material, suitable treatment is necessary. Sand dunes have typically been stabilized using a cement material, however, though extremely costly and consuming a substantial amount of energy, it is not particularly effective. Therefore, this study has investigated the potentiality of adding cement kiln dust (CKD) for enhancing the strength and durability of dune sands in Najran-Sharourah, SW Saudi Arabia. Twenty-seven specimens have been mixed with 0%, 10%, 20%, and 30% CKD plus 2% cement and then examined and assessed using macro-characterization techniques. Results indicated that the strength of the sand dune samples, treated with an enhanced mixture of 30% CKD and 2% cement, improved the minimum dry density from 1.652 at 0% to 1.854 g/cm3. The soil became more qualified as a construction material. This enhanced mixture can serve as a high-quality sub-base for both flexible and rigid pavements. Besides, micro-characterization techniques, including X-ray diffraction (XRD), back-scattered electron imaging (BEI), and scanning electron microscopy (SEM) supported by energy-dispersive X-ray (EDX), were applied to identify the various phases of the treated dune sands. Finally, the implementation of adding the CKD to the dune sands geomechanical parameters has been modeled, and a series of highly reliable mathematical equations have been introduced (0.938 <= R2 <= 1.0).

Improving the physical properties and water retention of sandy soils is of critical importance in arid and water-scarce regions such as Saudi Arabia. The impacts of organic amendments of different particle sizes coupled with natural clay deposits on improving the soil physio-chemical characteristics, nutrient availability, and growth of Sudan grass were investigated in this study. A loamy sand soil was amended with natural clay deposits at 2.5%, 5.0%, and 10% (w/w) application rates, and in combination with 1.0% (w/w) wheat straw of different particle sizes. The water infiltration, evaporation, and retention characteristics of the amended soil were studied for 9 weeks, and then Sudan grass was grown for 7 weeks. The impacts of the particle size of wheat straw on soil properties and nutrient availability were significant (p < 0.05) when combined with clay deposits. The highest application rate of clay (10%) demonstrated the highest water content (20.63-21.73%), and increased P and K availability to 35.54 and 6980 mg kg(-1), respectively, in soil, which were 33% and 88% higher, respectively, compared to the control. Plant N, P, and K concentrations were increased to 0.95%, 0.26%, and 4.33%, respectively, which were 2-3.5-fold higher than the control. Therefore, the integrated application of natural clay deposits and wheat straw of fine particle size could be an effective strategy in improving plant production in water-scarce regions.

Soil water is one of the fundamental conditions for the development of the forest ecosystems. Habitat conditions and forest tree composition are the basic factors influencing development of soil moisture. Tree growth and forest structure changes progress fluctuations in the hydric regime. The article evaluates development of soil moisture in different growth conditions of Scots pine stands on nutrient-poor sandy soils and defines the basic principles of these relationships. In 2018, the moisture of A horizon was measured in transects across the stands and clear-cut areas. In the period from 2018 to 2020, the vertical moisture profile was evaluated by means of dug probes under a mature stand of pine, on clear-cut area without soil preparation and in the space of the mounds and furrows on clear-cut area with soil prepared for natural regeneration by ploughing. The results showed that also in these conditions the moisture in the clear-cut area was all year round higher in comparison to the mature pine stand, however, topsoil moisture under the young pine growth with closed canopy was no longer different from the moisture of mature stand. Even in dry periods, the humidity on the clear-cut area decreased with the depth in the soil. Under the mature stand, this only happened when there was a sufficient amount of water in the ecosystem. The influence of the period within the growing season was not clearly reflected in the monitored long-term course of moisture in the soil horizons.

Land desertification is the key contradiction restricting the sustainable development of Chinese society. Farmers and herders' behavior in desert management is particularly important for the smooth development of the desertification control project. Although farmers and herders express willingness, they do not engage in desert management behavior. The research through random sampling survey analyzes survey data from 572 farmers and herders in the Kubuqi Desert region of Inner Mongolia using structural equation modeling and mediation analysis, based on the TPB. The aim is to understand the paradoxical willingness and behavior of farmers and herders to participate in desert management. The study found that farmers and herders' willingness to participate is a crucial factor that influences their behavior. The authors suggest cultivating a sense of ecological responsibility and strengthening ecological education to guide the behavior of farmers and herders towards more sustainable practices.

The China Desertification Ecological Restoration Project has effectively curbed the problem of soil desertification in Northwest China, and improved the ecological environment and landscape pattern of the Dunhuang Desertification Control Area. As the birthplace of Dunhuang culture, the ecological landscape of Yueyaquan Village shows strong sensitivity to disturbances, and in order to improve the ecological landscape resilience, an ecological landscape resilience evaluation system for desertification control villages was constructed from three levels: ecosystem, engineering system, and cultural traditions, and the results show that: (1) villages in the context of desertification control are difficult to resist the damages brought by natural disasters, and therefore the ability to resist determines the key factor of the ecological landscape resilience of villages. resilience level. (2) Through the empirical analysis of the ecological landscape system, engineering system and cultural system of Yueyaquan Village, it is found that the engineering system of the village has high resilience, the ecosystem resilience is average, and the resilience of the cultural system is weak, which reduces ecosystem resilience. The research results can guide subsequent improvement strategies for ecological landscape construction and provide new thoughts and ideas for rural environmental renovation and resilience enhancement.

Self-developed soil conditioner composites containing fermented chicken manure as a raw material alongside bentonite and super-absorbent polymer in different doses and combinations were tested in a 112 day long soil incubation experiment. This study aimed to determine their effects on soil N mineralization, and the changes in the amount of soil mineralized nitrogen forms, cumulative mineralized nitrogen (Nmin), min ), and C/N ratio in a sandy soil (Lamellic Arenosol) at two different soil water holding capacity (SWHC) levels and soil layers. Potentially mineralized nitrogen (PMN), net mineralization rates (NMR), and nitrification rates (NNR) were also calculated to study the effectiveness of treatments. Soil NH4-N 4-N decreased by 50-70% while NO3-N 3-N increased by 150-200% in the treated soil, so the NO3-N 3-N and NH4-N 4-N ratio changed from 1/3 to 2/1 during the incubation. N min gradually increased and was described by a linear tendency (R >= 0.99) for both soil layers and SWHC levels. Composite treatments increased significantly the PMN, and NMR values by 2-4 times and NNR values by 40-240% compared to the control. Applied composites enhanced the mineralized proportion of total nitrogen content by 2-6%. It was found that the composites were more effective at lower SWHC level and in their application layer than chicken manure alone. Overall, the developed organic-based composites are able to cope with changing soil conditions, which can help mitigate the negative effects of climatic anomalies, especially in arid areas with limited water resources by improving soil nutrient supply, thus contributing to sustainable nutrient management.