Soils In Arid Areas Research Articles

Effects of soil conditioners on vineyard saline soil physicochemical properties and bacterial community in arid areas

AbstractSoil salinization adversely affects soil quality and ecosystem. Many researches have tried to ameliorate saline soils by soil conditioners. However, little is known about the differences in the responses of soil bacterial communities to natural and artificial conditioners applied to saline soils. Therefore, in this study, the effects of natural humic acid (IK), synthetic polymer (IP), and composite material (IF) (mixture of IK and IP (1:1)) on bacterial community structure and functional genes in saline soil were evaluated to clarify their differences. The results showed that the application of the three soil conditioners significantly reduced soil pH and Na+ content but increased soil alkaline phosphatase, urease, invertase and catalase activities, bacterial diversity, and nutrients, compared to the control (no conditioner). IK application increased bacterial relative abundance (e.g., Subgroup_6, RB41, MND1, and KD4‐96) and metabolic functions (e.g., Two‐component system and Biosynthesis of amino acids) by increasing soil nitrogen and maintaining K+ and Na+ balance. IP application increased soil alkaline phosphatase and urease activities as well as bacterial relative abundance (e.g., Subgroup_6, RB41, MND1, Gemmatimonadaceae, and KD4‐96) and metabolic functions (e.g., Quorum sensing and carbon metabolism) by increasing soil organic carbon/nitrogen content. IF application increased the bacterial relative abundance of Subgroup_6, RB41, and MND1 by increasing soil available nitrogen and regulated their metabolic pathways (e.g., ABC transporters and microbial metabolism). On the whole, IK, IP, and IF could regulate the structure and function of soil bacterial community in saline soils. This study clarifies difference in the effects of different soil conditioners on the amelioration of saline soils from the perspective of soil microbiology, and provides a reference for the amelioration of saline soils in arid areas.

Seasonal and Depth Dynamics of Soil Moisture Affect Trees on the Tibetan Plateau

The soil moisture (SM) influences tree growth with climate change. However, the spatial and temporal dynamics of tree water use strategies in climate-sensitive areas remain uncertain. Therefore, we collected the tree-ring oxygen isotope (δ18OTR) chronologies and divided the wet–dry gradients according to the precipitation on the Tibetan Plateau (TP). Further, the relationship between the δ18OTR and environmental factors was analyzed across different gradients. We found the following: (1) The SM during the growing season was the most important factor for δ18OTR. (2) The response of the δ18OTR to the SM had a lag in arid areas than in humid areas. (3) Trees absorbed the SM on the surface in humid areas (r = −0.49 to −0.41, p < 0.01), while trees absorbed the SM from deep in the soil in arid areas (r = −0.48 to −0.29, p < 0.01). The results demonstrated that trees were better able to cope with drought stress in arid regions because they used more stable deep soil water than in humid regions. Therefore, the findings will provide a scientific basis for water use of trees using the δ18OTR in complex environmental contexts. Trees with single water use strategies should be given more attention to keep ecosystems healthy.

Vertical distribution of arsenic and bacterial communities in calcareous farmland amending by organic fertilizer and iron-oxidizing bacteria: Field experiment on concomitant remediation

The migration and transformation mechanisms of arsenic (As) in soil environments necessitate an understanding of its influencing processes. Here, we investigate the subsurface biogeochemical transformation of As and iron (Fe) through amended in the top 20 cm with iron oxidizing bacteria (FeOB) and organic fertilizer (OF). Our comprehensive 400-day field study, conducted in a calcareous soil profile sectioned into 20 cm increments, involved analysis by sequential extraction and assessment of microbial properties. The results reveal that the introduction of additional OF increased the release ratio of As/Fe from the non-specific adsorption fraction (136.47 %) at the subsoil depth (40–60 cm), underscoring the importance of sampling at various depths and time points to accurately elucidate the form, instability, and migration of As within the profile. Examination of bacterial interaction networks indicated a disrupted initial niche in the bottom layer, resulting in a novel cooperative symbiosis. While the addition of FeOB did not lead to the dominance of specific bacterial species, it did enhance the relative abundance of As-tolerant Acidobacteria and Gemmatimonadetes in both surface (39.2 % and 38.76 %) and deeper soils (44.29 % and 23.73 %) compared to the control. Consequently, the amendment of FeOB in conjunction with OF facilitated the formation of poorly amorphous Fe (hydr)oxides in the soil, achieved through abiotic and biotic sequestration processes. Throughout the long-term remediation process, the migration coefficient of bioavailable As within the soil profile decreased, indicating that these practices did not exacerbate As mobilization. This study carries significant implications for enhancing biogeochemical cycling in As-contaminated Sierozem soils and exploring potential bioremediation strategies. Environmental implicationThe long-term exposure of sewage irrigation has potential adverse effects on the local ecosystem, causing serious environmental problems. Microorganisms play a vital role in the migration and transformation of arsenic in calcareous soil in arid areas, which highlights the necessity of understanding its dynamics. The vertical distribution, microbial community and fate of arsenic in calcareous farmland soil profile in northwest China were studied through field experiments. The results of this work have certain significance for the remediation of arsenic-contaminated soil in arid areas, and provide new insights for the migration, transformation and remediation of arsenic in this kind of soil.

Групповой и фракционный анализ гумуса каштановых почв аридных территорий Дагестана

Групповой и фракционный анализ гумуса каштановых почв аридных территорий Дагестана

Preparation of carbon-based material with high water absorption capacity and its effect on the water retention characteristics of sandy soil

Biochar has the potential to provide a multitude of benefits when used in soil remediation and increasing soil organic matter enrichment. Nevertheless, the intricated, hydrophobic pores and groups weaken its water-holding capacity in dry, sandy soils in arid lands. In order to combat this issue, starch-carbon-based material (SB), sodium alginate-carbon-based material (SAB), and chitosan-carbon-based material (CB) have been successfully synthesized through the graft-polymerization of biochar (BC). A series of soil column simulations were used to scrutinize the microstructure of the carbon-based material and explore its water absorption properties and its effects on sandy soil water infiltration, water retention, and aggregation. The results indicated that SB, SAB, and CB achieved water maximum absorption rates of 155, 188, and 172 g g−1, respectively. Considering their impact on sandy soils, SB, SAB, and CB lengthened infiltration times by 1920, 3330, and 3880 min, respectively, whilst enhancing the water retention capabilities of the soil by 18%, 25%, and 23% in comparison to solely adding BC. The utilization of these innovative materials notably encouraged the formation of sandy soil aggregates ranging from 2.0 to 0.25 mm, endowing the aggregates with enhanced structural stability. Findings from potting experiments suggested that all three carbon-based materials were conducive to the growth of soybean seeds. Thus, it is evident that the carbon-based materials have been fabricated with success, and they have great potential not only to significantly augment the water retention capacities and structural robustness of sandy soils in arid areas, but also to bolster the development of soil aggregates and crop growth. These materials possess significant application potential for enhancing the quality of sandy soils in arid and semi-arid regions.Graphical

Effects of biochar on soil evaporation and moisture content and the associated mechanisms

High soil evaporation levels are a major contributor to loss of soil moisture in arid and semiarid regions globally. Therefore, it is important to use effective measures to slow the evaporation from farmland soils. We applied various amounts of straw biochar (BC) in a soil column experiment and a field experiment to study the influence of BC on soil evaporation and moisture content, respectively, to improve the water use efficiency of cultivated soil in arid areas. The addition of BC reduced soil evaporation and delayed water loss from the soil by evaporation. In the field experiment, cumulative evaporation in the treatments declined by 9.58% (Bo-10), 10.95% (Bo-30), and 4.2% (Bo-50) compared with that in the control group, demonstrating that 30 t/hm2 BC is the most effective at suppressing soil evaporation. BC also delayed the time required for the soil moisture content to drop to field capacity and increased the upward transport of water from the deeper soil layers at night. Data from continuous monitoring of moisture content for 3 days during each growth period revealed that the increases in moisture replenishment were 18.52–79.62% at the seedling stage, 55.81–202.38% at the jointing stage, 270.83–587.5% at the tassel stage, and 6.66–61.64% at the maturation stage; hence, BC was shown to work best at the tassel stage.

Growth, Physiology, and Productivity of Bouteloua gracilis and Cenchrus ciliaris Using Moisture Retainers under Different Planting Methods

The extensive raising of livestock on grasslands is a relevant economic activity in northern Mexico. These are regions of high climatic uncertainty and have extreme weather events, which requires the exploration of technological innovation to mitigate the negative impacts on these agroecosystems. The aim of this study was to evaluate two grass species using two planting methods and two types of soil moisture retainers and to determine their response based on growth and some physiological and productive attributes. A randomized complete block design (RCBD) was used in a split–split plot arrangement with six replications. The main plots were planted with two grass species: Bouteloua gracilis and Cenchrus ciliaris; the subplots were differentiated by two grass planting methods: seeding and seedling transplanting; the sub-subplots were differentiated by the soil moisture retainers used: (1) application on the soil of 10 t ha−1 of corn harvest residue (CHR) as organic cover on the soil surface, (2) application of hydrogel at 20 kg ha−1 mixed in the soil rhizosphere because it must be in contact with the root and soil due to its chemical composition, and (3) control, no application of any type of input. The seedling transplant method with the application of CHR significantly increased (p < 0.05) the plant survival percentage, on average by 31.5% in both grasses, in relation to the direct method seeding and the control. C. ciliaris showed a higher photosynthetic rate and, therefore, higher forage productivity than B. gracilis. The hydrogel only showed a moisture retention effect in the soil during the first 20 days after the transplant or sowing of the grass seed; after this period, there was no longer any effect as a water retainer in the soil. The soil cover with CHR was confirmed as a good moisture retainer with greater productivity of rangeland forage in degraded soils in arid areas.

Tomato waste biochar in the framework of circular economy

Tomato pomace was slowly pyrolyzed at 350 and 550 °C (under an N2 flow of 50 L/h) at a rate of 6 °C/min and a residence time of 1:30 h to produce two biochars named B350 and B550, respectively. In addition, the two biochars were chemically activated with ΚΟΗ (at a ratio of 1:10 w/v) at 800 °C to produce two new materials named BA350 and BA550. The four biochars produced were characterized physically and chemically (pH, yield, calorific value). They were also analyzed by scanning electron microscopy (SEM), Brunauer–Emmett–Teller (B.E.T), elemental analysis (EA), and thermogravimetric analysis (TGA). The results showed that as the pyrolysis temperature increased (350 to 550 °C), the specific surface area (SSA) increased. The latter was also significantly increased by the activation process. EA showed a variation in the mineral content of the produced biochars, resulting in a different content of the biochars after activation. The parameters studied showed that biochars from tomato waste could be used as an organic amendment to improve soil fertility in agricultural. In addition, because of their ability to absorb water, they could be used as a water reservoir in soils in arid areas.

An Improved Exponential Model Considering a Spectrally Effective Moisture Threshold for Proximal Hyperspectral Reflectance Simulation and Soil Salinity Estimation

Soil salinization has become one of the main factors restricting sustainable development of agriculture. Field spectrometry provides a quick way to predict the soil salinization. However, soil moisture content (SMC) seriously interferes with the spectral information of saline soil in arid areas. It is vital to establish a model that is insensitive to SMC for potential in situ field applications. The soil spectral reflectance exponential model (SSREM) has been widely employed for reflectance simulation and SSC inversion. However, its reliability for saline soils with high SMC has not been verified yet. Based on hyperspectral remote sensing data (400~1000 nm) on 459 saline soil samples in Shiyang River Basin of Northwest China, we investigated the role of SMC and SSC in soil spectral reflectance from 29 October 2020 to 22 January 2021. Targeted at saline soils, soil spectral moisture threshold (MT) was introduced to improve the SSREM toward a modified spectral reflectance exponential model (MT-SSREM). The bands that are sensitive to SSC but not sensitive to SMC were obtained based on a method of correlation analysis between original spectra, four kinds of spectral data, and SSC. SSREM and MT-SSREM were finally applied to inversely estimate SSC. Results show that wavelengths at 658~660, 671~685, 938 nm were suitable for SSC estimation. Furthermore, although SSREM was able to simulate the spectral reflectance of most saline soils, its simulation accuracy was low for saline soil samples with high SMC (SMC > MT(i), 400 nm≤i≤1000 nm), while MT-SSREM performed well over the whole range of SMC. The simulated spectral reflectance from MT-SSREM agreed well with the measured reflectance, with the R2 being generally larger than 0.9 and RMSE being less than 0.1. More importantly, MT-SSREM performed substantially better than SSREM for SSC estimation; in the statistical performance of the former case, R2 was in range of 0.60~0.66, RMSE was in range of 0.29~0.33 dS m−1; in the latter case, R2 was in range of 0.10~0.16, RMSE was in the range of 0.26~0.29 dS m−1. MT-SSREM proposed in this study thus provides a new direction for estimating hyperspectral reflectance and SSC under various soil moisture conditions at wavelengths from 400 to 1000 nm. It also provides an approach for SSC and SMC mapping in salinization regions by incorporating remote sensing data, such as GF-5.

Optimization of Urease Production Capacity of a Novel Salt-Tolerant Staphylococcusxylosus Strain through Response Surface Modeling

Encouraging advances have been made in the application of microbial mineralization towards fixing and improving desertified sandy soils. However, desert soils in arid areas exhibit high salinity that may limit urease activity and production in microbial strains, thereby affecting the solidification effects of microbial calcium binders in saline soils. In this study, a salt-tolerant microbial strain (A80) that produced urease was identified from saline soils of the Qaidam Basin. The culture conditions of the strain were optimized using single-factor tests and response surface methods to optimize urease yields and activity. The optimal composition of the A80 medium included an inoculation amount of 6.32% (V/V), a yeast extract powder concentration of 15.43 g/L, a glucose concentration of 5.20 g/L, a salinity of 3%, and an incubation temperature of 36 °C. Urease activity increased by 64.80% after using optimized medium. The A80 microbial calcium-cementing agent was also used to solidify saline soils, leading to an increased unconfined compressive strength of the solidified saline soil by 25.70%. Thus, the optimization method resulted in improvements in the cultivation of a salt-tolerant strain.

Distinct soil microplastic distributions under various farmland-use types around Urumqi, China

Very little is known about the occurrence of microplastics in the soils of various land uses, especially their distributional characteristics in the soils of arid areas. In this study, 24 sampling sites across three soil layers were investigated for three different farmland-use types (greenhouses, crop fields and vegetable fields) in the main agricultural and pastoral areas around Urumqi, China. The results demonstrated that the dominant sizes of soil microplastics were 0.2–0.5 and 0.5–1.0 mm, the main shape was film (85.93 %), the main color was white, and the main polymer was polyethylene (93.1 %), indicating that most microplastics derive from the damage to residual mulches. The microplastics abundance was highest in the greenhouse plots (7763 ± 2773 items/kg), followed by the vegetable plots (4128 ± 2235 items/kg) and then the crop fields (3178 ± 3172 items/kg). No significant differences were observed among the abundances of microplastics in the 0–10 cm (1822 ± 1345 items/kg), 10–20 cm (1566 ± 1139 items/kg) and 20–30 cm (1309 ± 1028 items/kg) layers, suggesting that microplastics can migrate to the deeper soil layer and are strongly influenced by tillage disturbance. The abundance of microplastics in the north of Urumqi was found to be higher than in the south, which is closely related to the division of agricultural functional zones and the intensity of agricultural management practices. It was found that different cropping characteristics and modes of agricultural use affect the abundance and migration of microplastics in various farmland-use types, and thus their distribution. This study provides important data for follow-up research on microplastics in arid terrestrial ecosystems, and corresponding policy-making on the management of these materials.

Estimation of SO42− ion in saline soil using VIS-NIR spectroscopy under different human activity stress

SO42− ion is an important indicator of soil salinization degree, but there are few researches on quantitative inversion of SO42− content based on hyperspectral and fractional-order derivative (FOD). This study aimed to improve the prediction accuracy of SO42− content in arid regions using visible and near-infrared (VIS-NIR) spectroscopy. The study area was divided into three regions according to different human activity stress, namely, lightly affected region (Region A), moderately affected region (Region B) and severely affected region (Region C). The combination estimation method of spectral transformations (R, R, 1/R, lgR, 1/lgR), FOD, significance test band (STB), and partial least squares regression (PLSR) were been constructed, and four models (FULL-PLSR, FOD-FULL-PLSR, IOD-STB-PLSR, FOD-STB-PLSR) were also used to compare and analyze the estimation accuracy. Simulation results show that the optimal prediction model of three regions is FOD-STB-PLSR, its spectral transformation is established by R, 1/R and R in Region A, B, and C, respectively. Its RPD is 2.4701, 3.4679 and 1.9781, and its optimal FOD derivative is located at 1.8-, 1.1- and 1.1-order, respectively. It means that FOD can fully extract VIS-NIR spectroscopy details, the higher-order FOD is more capable of extracting characteristic data than low-order FOD, and the predictive ability of the best estimation model is very good, extremely strong and relatively good in Region A, B and C, respectively. Compared with the best IOD-STB-PLSR of each region, the RPD of the optimal FOD-STB-PLSR model has increased more than 38%, 32%, and 19%, respectively. This study shows that the proposed FOD-STB-PLSR model is suitable for estimating the SO42− ion content of saline soil under different human activity stresses, and the study can provide a certain technical reference value for the monitoring of saline soil in arid areas.

Effect of Sodium Carboxymethyl Cellulose on Water and Salt Transport Characteristics of Saline-Alkali Soil in Xinjiang, China.

The scientific use of sodium carboxymethyl cellulose (CMC) to improve the production capacity of saline–alkali soil is critical to achieve green agriculture and sustainable land use. It serves as a foundation for the scientific use of CMC to clarify the water and salt transport characteristics of CMC-treated soil. In this study, a one-dimensional soil column infiltration experiment was carried out to investigate the effects of different CMC dosages (0, 0.2, 0.4, 0.6, and 0.8 g/kg) on the infiltration characteristics, infiltration model parameters, water and salt distribution, and salt leaching of saline–alkali soil in Xinjiang, China. The results showed that the final cumulative infiltration of CMC-treated soil increased by 8.63–20.72%, and the infiltration time to reach the preset wetting front depth increased by 1.02–3.96 times. The sorptivity (S) in the Philip infiltration model and comprehensive shape coefficient (α) in the algebraic infiltration model showed a trend of increasing first and then decreasing with CMC dosage, revealing a quadratic polynomial relationship. The algebraic model could accurately simulate the water content profile of CMC-treated soil. CMC enhanced the soil water holding capacity and salt leaching efficiency. The average soil water content, desalination rate, and leaching efficiency were increased by 5.18–15.54%, 21.17–57.15%, and 11.61–30.18%, respectively. The effect of water retention and salt inhibition on loamy sand was the best when the CMC dosage was 0.6 g/ kg. In conclusion, the results provide a theoretical basis for the rational application of CMC to improve saline–alkali soil in arid areas.

Anthropogenic and Natural Influences on Soil Organic Carbon Fractions: A Case Study on Soils of Meyghan Lake in Arak, Iran

Monitoring and assessment of soil organic carbon (SOC) in the soils of arid areas are very important. The objectives of the study were to evaluate the responses of extractable and particulate organic matter in soils around Meyghan Lake in Arak (Iran) to surface water-inflows. Two layers (0-30 cm and 30-60 cm) of soils were sampled in the release sites of municipal wastewater and 3 rivers. Different fractions of SOC were measured and statistically analyzed. The soil sampled from the release sites of municipal wastewater had the highest total organic carbon (14.1 mg TOC g-1 topsoil) and free particulate organic matter (8.07 mg FPOM g-1 topsoil) due to better soil condition for plant growth. In contrast, the soil sampled from the release sites of wastewater of sodium sulfate plant had the lowest the total organic carbon (3.50 mg TOC g-1 topsoil) and all of the fractions. The cold water extractable OC (CWEOC), occluded particulate organic matter (OPOM) and the heavy fraction (HF) as slow fractions responded to soil sampling time better than active fractions. They significantly increased in the soils sampled in fall. The means of CWEOC, hot water extractable OC (HWEOC) and OPOM were higher in the soils sampled from the eastern part of the lake with higher clay and moisture contents and lower elevation. They responded better to the soil properties controlling the biological activity and biodegradation. The best fraction for the study of short-term changes of SOM by anthropogenic and natural effects was FPOM in these non-agricultural lands.

Effect of vapour-solid interfacial adsorption on benzene multiphase partition and its implication to vapour exposure assessment of contaminated soil in arid area

The partitioning of volatile organic compounds (VOCs) in soil multiphase system is a critical process for vapour intrusion, however, the importance of vapour-solid interface adsorption doesn't receive the due attention, which causes the exposure assessment too conservative particularly in arid conditions. This paper proposed a multiphase partitioning equilibrium (MPE) model establishing the quantitative relationship between VOCs and its various partitioning phases in soil, including solid-liquid interface adsorption phase, vapour phase and dissolved phase and vapour-solid interface adsorption phase. Taking benzene as the targeted pollutant, the model was found in good agreement with the experimental data while the errors were within one magnitude basically. The role of vapour-solid interface adsorption under different soil moisture conditions was also investigated by the model. The results reveals that a) soil moisture is the conspicuous controlling factor that affects the benzene partitioning in soil; b) vapour-solid interface adsorption dominates benzene uptake when soil relative saturation (RS) is under 20% among three typical soils; c) as adsorption by soil minerals (vapour-solid interface adsorption) is reduced by increasing amounts of humidity (RS > 20%), uptake by partitioning into the soil organic matter (OM) increasingly becomes a controlling factor; d) the common sense that vapour concentration of benzene is particularly high with low level of RS may not occur since the vapour-solid interface adsorption dominates benzene uptake in arid environment. The MPE model is suitable for prediction of VOCs partitioning and vapour exposure risk assessment of contaminated soil in arid area.

Effect of Long-Term Fertilization on Aggregate Size Distribution and Nutrient Accumulation in Aeolian Sandy Soil.

Soil aggregates are the material basis of soil structure and important carriers of nutrients. Long-term application of organic and inorganic fertilizers can affect the composition of soil aggregates to varying degrees, which in turn affects the distribution and storage of soil nutrients. We report the results of a 15-year long-term field-based test of aeolian sandy soil and used the wet sieve method to analyze the stability of water-stable aggregates, as well as the distribution characteristics of nutrients in different particle size aggregates. Our results show that long-term application of organic fertilizer (M3) and combined organic–inorganic treatments (NPK1-M1, NPK1-M2, and NPK1-M3) help to increase the amount of organic carbon, inorganic carbon, and cation exchange in the macro-aggregates, and the improvement rates are 92–103%, 8–28%, and 74–85%, respectively. The organic content of the fertilizers also promotes the formation of macro-aggregates, and the stability of aggregates increase from 0.24 to 0.45. In contrast, the application of inorganic fertilizers (NPK1, NPK2, and NPK3) has no marked effect on the formation and stability of macro-aggregates; the application of inorganic fertilizers can merely maintain the organic carbon content of the soil. Correlation analysis shows that the application of organic fertilizers and chemical (inorganic) fertilizers containing phosphorus and potassium can markedly increase the content and reserves of available phosphorus and potassium across all aggregate sizes, and there is a significant positive correlation between these parameters and the amount of applied fertilizer (p < 0.05). Aggregates of various sizes in aeolian sandy soils in arid areas have the potential for greater nutrient storage. Therefore, organic fertilizers can be used in the agricultural production process to improve soil structure and fertility.

Nitrogen input leads to the differential accumulation of polycyclic aromatic hydrocarbons in the low- and high-density fractions in sewage-irrigated farmland soil

Because of a shortage of water resources, sewage irrigation has become a popular management tool for farmland soil in arid areas of China; however, this has led to the accumulation of polycyclic aromatic hydrocarbons (PAHs) in soil. Soil is an important component of ecosystems, and nitrogen is an important nutrient required for plant growth. Nitrogen input can alter the physical, chemical, and biological processes in soil and thus lead to changes in soil organic matter and organic pollutants. However, whether these changes affect the accumulation of PAHs and whether such accumulation differs in the low-density fraction (LF) and high-density fraction (HF) of soil remains unclear. In this study, the response of PAHs in soil to nitrogen input (0, 100, 200, and 300 kg N ha−1 yr−1, respectively), including differences in LF and HF, were investigated through field experiments in a typical sewage-irrigated area. The results showed that nitrogen input could increase the concentrations of PAHs in soil from (7.6 ± 1.1) × 103 to (10.4 ± 0.6) × 103 μg kg−1 and lead to striking differences between the LF ((5.06 ± 0.75) × 103 to (1.89 ± 0.18) × 103 μg kg−1) and HF ((2.54 ± 0.36) × 103 to (8.54 ± 0.44) × 103 μg kg−1). Given the significant increase in global nitrogen input, our findings have implications for the optimization and management of agricultural activities in sewage irrigation areas, such as soil investigation before fertilization, the use of soil improvers, and the improvement of soil planting measures.

An electronic irrigation system using IoT and neural networks

One of the approaches that fall under the alternative application of water on earth or soil is electronic irrigation. It is aware of the need to irrigate crops, restore the vegetation of difficult soil in arid areas, and because of dry spells, as our state has experienced in recent years. Other issues, such as increasing plant growth while lowering the value of agriculture, necessitate installing an irrigation system that cuts back effort, reduces farm and field employees, and minimizes monetary matters within the construction of agricultural comes is crucial. Soil wetness measure is incredibly tough; thus the economic maintaining of its target levels. The answer to this drawback is an automatic irrigation system. This analysis proposed an electronic irrigation system that reduces users' effort to plant care. The system kernel is the self-learning Kohonen Neural Network, which depends on the reading of the detector of soil wetness, plant type, and forecast data. The soil wetness detector indicates the soil wetness level. Also, the system is mechanically started once the wetness level is not up to the extent necessary for the plant's growth. When the system reaches the soil wetness level, it is mechanically stopped for a defined period of morning and evening. As a soil wetness level differs from one plant kind to a different, 3 plant varieties area unit used during this analysis. Beginning the system littered with the weather data, is saving time and effort for the employees.

Investigation of Evaporation and Cracking of Soil Reinforced with Natural and Polypropylene Fibers

ABSTRACT In this paper, the evaporation and cracking characteristics of soils reinforced with straw and polypropylene fibers are studied. The changes in moisture content during evaporation are measured by using a high precision platform scale and the development of surface cracks is captured with a digital camera. The results are analyzed by using a GIS (Geographic Information System) software and the crack ratio and fractal dimension of the cracks are calculated. The results show that the final average moisture content after evaporation of the soils with straw and polypropylene fibers is increased by 69.90% and 49.75%, respectively, compared with the soil without fibers. The rate of evaporation can be divided into three stages: Stage I: Initially stable; Stage II: Decreases rapidly, and Stage III: Decreases slowly and tends to be stable. The time of the appearance of the first crack in the soil without fibers is earlier than that in the soils with fiber reinforcements. The final crack ratio of the soils with straw and polypropylene fibers is reduced by 6.79% and 14.16% compared to the soil without fibers. Therefore, adding fiber to soil can reduce water evaporation and inhibit cracking which provides a technique for improving soils in arid areas.

The Ecological Relationship of Groundwater–Soil–Vegetation in the Oasis–Desert Transition Zone of the Shiyang River Basin

Groundwater is an important ecological water source in arid areas. Groundwater depth (GWD) is an important indicator that affects vegetation growth and soil salinization. Clarifying the coupling relationship between vegetation, groundwater, and soil in arid areas is beneficial to the prevention of environmental problems such as desertification and salinization. Existing studies lack research on the water–soil–vegetation relationship in typical areas, especially in shallow groundwater areas. In this study, the shallow groundwater area in Minqin, northwest China, was taken as study area, and vegetation surveys and soil samples collection were conducted. The relationships between vegetation fractional coverage (VFC) and GWD, soil salinity, soil moisture, and precipitation were comprehensively analyzed. The results showed low soil salinity in the riparian zone and high soil salinity in other shallow-buried areas with salinization problems. Soil salinity was negatively correlated with VFC (R = −0.4). When soil salinity &gt;3 g/kg, VFC was less than 20%. Meanwhile, when GWD &gt;10 m, VFC was usually less than 15%. In the areas with soil salinity &lt;3 g/kg, when GWD was in the range of 4–10 m, VFC was positively correlated with soil moisture content (R = 0.99), and vegetation growth mainly depended on surface soil water, which was significantly affected by precipitation. When GWD was less than 4 m, VFC was negatively correlated with GWD (R = −0.78), and vegetation growth mainly relied on groundwater and soil water. There are obvious ecological differences in the shallow-buried areas in Minqin. Hence, it is reasonable to consider zoning and grading policies for ecological protection.