Morphometry and formation processes are key research problems in the study of aeolian sandy land-forms. Based on morphometric parameters inferred from satellite images and the calculation of the drift potential (DP), we examined general characteristics of lunette dunes in the Tirari Desert, South Australia, along with their morphometry and formation processes to determine how this landform type initially formed and its relationship to surrounding linear dune distribution. Results show that the morphometric parameters of lunette dunes and connective lake systems exhibit moderate correlations. It suggests that the morphology of these dunes is controlled by the lakes. Spatially, the lunette dunes present regular arrangement, and the strike of their alignment are approximately in accordance with the linear dunes. The calculated DP implies that the lunette dunes developed under a lowwind-energy environment, which is a wind regime similar to that required for the formation of the surrounding linear dunes. Even though, the resultant DP demonstrates that the summer wind should be responsible for the growth of the lunette dunes. However, accompanied with the repeated drying of lakes and even its disappearance during the dune development process, it not only contributes to the development of lunette dunes but also promotes their transformation to linear dunes.

Umbrisols generally develop in a cool and humid climate. Therefore, occurrence of these soils in the Borska lowland of southwestern Slovakia is very uncommon, and this inspired the aim of this paper: Analysis of the natural conditions suitable for Umbrisol development. Umbrisols in the Borska lowland developed from aeolian quartz sands accumulated on Neogenne marine clay sediments. Their occurrence is connected with the groundwater table relatively close to the ground surface and this particularly determines Umbrisol genesis in this area. Sufficient input via organic matter is an important factor for formation of the umbric horizon, and only the rich herbaceous undergrowth of the prevailing planted pine and mixed pine-oak forests is capable of providing it. A growth of diep-rooted grass is closely connected with higher soil moisture content, and quite moist areas occur in the deeper inter-dunes depressions. Constant soil moisture in these sites is facilitated by water capillary elevation. While Umbrisols are transformed to Arenosols at increased altitude, they can be transformed to Gleysols in deep depressions. Herein, induced polarization provided suitable geophysical method for detection of arenic Umbrisol inclusions. Sharp transformation of the humus layer to dry non-polarized aeolian quartz sands enabled the surface horizon to be distinguished by induced polarization.

While more than half the land surface of Iraq consists of deserts covered mainly with sand dunes, little research has taken place to study the characteristics and the behaviour of sand dunes. The growth of economy, demography and building activities in Iraq necessitates carrying out geotechnical investigations for the dune sand. The purpose of the present work is to assess the suitability of sand dunes as subgrade layer for carrying roads and rail foundations. An extensive laboratory testing programme was carried out to study the geotechnical properties and the behaviour of sand dunes. Sand dune samples were collected from a region in Baiji area in Salah-Aldeen governorate, North of Iraq, in situ field density of the soil was measured by sand-cone test. The tests include moisture content, classification tests, compaction tests, relative density and direct shear test. Chemical tests and X-ray diffraction analyses were also carried out. Silica fume (SF) and lime-silica fume (L-SF) mix have been used for stabilising and their effects on the sand dunes were investigated. A grey-coloured densified SF is used. Four percentages are used for lime 0, 3, 6 and 9% and four percentages are used for SF 3, 6, 9 and 12% and the optimum percentage of SF is mixed with the percentages of lime. Several tests are made to investigate the soil behaviour after adding the lime, and SF. It was found that L-SF caused an increase in the angle of friction phi and cohesion c. Higher cohesion was reached; 10 kPa with higher percentage of 6% L + 12% SF. In addition, the angle of internal friction increases with increasing the maximum dry density, where the values of the angle of internal friction ranged between 35 degrees and 41 degrees.

A dynamic vegetation-sand-grazer model is proposed in this research, to study the effects of different grazing intensities on the growth of vegetation in arid and semi-arid areas. The model is established on the basis of three processes: the growth of vegetation, the deposition of aeolian sand, and the growth of grazers (some herbivores). The equilibrium of the model is obtained through stability analysis and this reveals that vegetation can survive in an environment of both sand burial and grazers. But we all know that overgrazing will cause desertification. Therefore numerical simulations are carried out to quantitatively demonstrate the variations of the equilibrium along with different grazing intensities and the relationships between grazing intensity and the three variables of vegetation cover, aeolian sand and grazers. During stability analysis and simulation, we obtain several critical points of the vegetation-sand-grazer system, such as grazers bringing in point, point of maximum volume of grazers, Hopf bifurcation point and the initial grazers with respect to the projection of separatrix on vegetation-aeolian sand plane. And based on these critical points, the process of desertification can be divided into four stages: healthy (no grazing and moderate grazing), passive desertification, active desertification (overgrazing), and ecosystem collapse. The new perspective in this research may promote the understanding of desertification process and may also provide useful information for the management of graziery.

Both the plant growth promoting rhizobacteria (PGPR) and plant growth regulators (PGR) exert beneficial effects on plant growth even under stress, but combined effect of both of them has not been evaluated yet. Present investigation was aimed to determine the responses of 2 chickpea varieties (differing in drought tolerance) to 3 PGPR viz. Bacillus subtilis, Bacillus thuringiensis and Bacillus megaterium and PGR (SA and Putrescine) on physiology of chickpea grown in sandy soil. The PGR, Salicylic acid (SA) and Putrescine (Put) were sprayed on the seedling 20 days after germination. Results revealed, synergistic effects of PGPR and PGR on chlorophyll, protein and sugar contents. Addition of PGR to PGPR inoculated plants assisted the plant in osmoregulation and amelioration of oxidative stresses and in induction of new proteins. Combined application of PGR and PGPR decreased lipid peroxidation more effectively but increased the leaf area. It is inferred that PGPR and PGR work synergistically to promote growth of plants under moisture and nutrient deficit condition of sandy soil. Since, SA induces Systemic Acquired Resistance (SAR) in plants hence the addition of SA along with PGPR may render the plant more productive and better tolerant to diseases/pathogen attack.

Arbuscular mycorrhizal fungi (AMF) exist in herbaceous plants' rhizospheres from the Black Sea temperate zone. The AMF is significant for herbaceous plants during their life processes and stages; it has vital importance under the marginal climate conditions and protects plants against soil borne diseases. The aim of this research is to investigate the symbiotic status of AMF species with Cynodon dactylon (L.) PERS., within the temperate coastal regions of the Black Sea. In order to achieve this aim, 20 samples of Bermuda grass were collected from the study area. AMF spore abundance and diversity were determined in the study area during the 2016 dry season. Also, physical and chemical properties of the rhizosphere soils were analyzed, including the pH, CaCO3 content, organic carbon, available P, available K, soil texture, and total N. Furthermore, 12 arbuscular mycorrhyzal fungi species were diagnosed. Identified spores belonged to Ambispora, Dentiscutata, Funnelifornzis, Cetraspora, Claroideoglonius, Acaulospora, Scutellospora, Rhizoglomus, and Gigaspora genus. The diagnosed dominant AMF genus was Gigaspora. The soil of rhizosphere had low organic carbon, low available P, low available K, low total N, high CaCO3 content, almost neutral pH, and sandy soil. The symbiotic status of Cynodon dactylon with arbuscular mycorrhizal fungi species demonstrated that the indigenous Cynodon dactylon carried substantial potential as a host plant for AMF species in sandy soils from Black Sea temperate coastal regions.

This study evaluated wheat production effects on carbon (C) fractions and soil organic C (SOC) molecular composition of a semiarid Plinthustalf in a trial established near Bethlehem. Treatments applied for 20 consecutive years included two straw management (unburned and burned), three tillage (no-tillage, ploughing and stubble mulch) and two weed control (chemical and mechanical) methods. Samples collected from 0-50mm depth of specific treatment combinations were analyzed for SOC, soil inorganic C (SIC), permanganate oxidizable C (POXC), cold (CWEC) and hot (HWEC) water extractable C, extractable humic substances (CEX), humic acids, fulvic acids (CFA) and SOC functional groups. Humification (HI) and polymerization (PI) indices and alkyl C/O-alkyl C ratios were calculated. No-tillage combinations demonstrated potential to reverse losses of soil C fractions in the 0-50mm layer. Increased POXC, CWEC, CEX and CFA revealed the labile nature of accumulated SOC in no-tillage, suggesting that SOC therein could be rapidly lost if no-tilled soils were again cultivated. Although the HI and PI were not always significant, their decrease in the no-tillage combinations suggest minimal decomposition, which is a benefit in Plinthustalfs with low storage capacity. Positive correlations between SIC and SOC fractions implied that an increase in SOC fractions protected SIC, resulting in its accumulation in no-tillage combinations. Functional groups seemed to mimic fractionated SOC fractions because O-alkyl C decreased with concomitant increase in alkyl, aromatic and carbonyl C. These responses highlighted that no-tillage combinations could be ideal to restore SOC quality in drought-prone agro-ecosystems dominated by sandy soils.

Collapsed walls cause collapsed mounds, and the disintegration characteristics of collapsed walls are thus closely linked with the occurrence of collapsed mounds. The current study examines the disintegration characteristics and the physical and chemical properties of collapsed walls. A multilevel analysis was conducted by obtaining soil samples from four layers of a collapsed wall. The results showed that 1) the physical and chemical properties of the soil samples (red soil layer, sandy soil layer, debris layer, gravel and eluvial breccia) are closely related to the weathering degree of the crust; 2) gravel and eluvial breccia disintegrated in the shortest time, whereas red soil exhibited the slowest disintegration in the vertical of the collapsed wall. The order of the disintegrating ratio of the layers is as follows: red soil layer < sandy soil layer < debris layer < gravel and eluvial breccia. Initial water content significantly influenced the disintegration ratio of the red soil layer and sandy soil layer, whereas its effect on the debris layer and gravel eluvial breccia is minimal; and 3) most of the physical and chemical properties of the collapsed wall are significantly correlated with the disintegration ratio of the soil sample. The following physical and chemical properties, which are positively correlated with the disintegration ratio, are arranged based on highest to lowest correlation coefficient: sand content, MgO, natural water content, K2O, CaO, exchangeable sodium, pH, porosity, Na2O, and cation exchange capacity. The following physical and chemical properties, which are negatively correlated with the disintegration ratio, are organized based on highest to lowest correlation coefficient: cosmid, Fe2O3, silt particle, Al2O3, TiO2, SiO2, organic matter, free iron oxide, and free alumina. Only exchangeable calcium, saturated water content, specific gravity of soil particles, and dry density of soil particles are significantly correlated with the disintegration ratio. The correlation coefficient indicates that the disintegration ratio and soil structure, as well as the chemical content oaf clay minerals, are closely correlated. The study helps explain the mechanism of wall collapse and provides references for developing protective measures against erosion.

The aim of this study was made to compare the nutrient composition of 7 selected varieties of sorghum. The comparison was done two different localities, with different soil types (clay loam soil - fluvial soil and light sandy soil) in the region of South Moravia. The sampling of sorghum varieties were at two different locations and was realized 12 weeks after sowing, followed by analysis of nutrient composition as dry matter, N-substances, fibre, ADF - Acid Detergent Fibre and NDF - Neutral Detergent Fibre. Based on the data found it was concluded that it depends more on sorghum variety and its form than on the soil type.

The construction of corresponding match of rocky desertification characteristic information and control mode is the focus and also the difficulty of rocky desertification research. With various ecological, social and economic indicators in the area of rocky desertification as the research object, the data mining theory is innovatively integrated with the regional rocky desertification control mode in this paper. Based on the reasoning of different types of rocky desertification and the combination of bee colony algorithm and BP neural network, this paper is to guide the selection of rocky desertification control mode. Those areas where rocky desertification has been successfully prevented and controlled will be saved in the system as excellent categories. For those new areas needing rocky desertification prevention and control, we can search for similar control mode in the system and modify it to get a suitable one and then to guide relative comprehensive management work. Experimental results show that the proposed method is effective in practice.