Search Results (143)

Desert plant communities play a vital role in sustaining the stability of arid ecosystems; however, they demonstrate limited resilience to environmental changes. A critical aspect of understanding community assembly mechanisms is determining whether soil texture heterogeneity affects vegetation diversity in arid deserts, especially under conditions of extreme water scarcity and restricted nutrient availability. This study systematically examined the relationships between plant diversity and soil physicochemical properties across four soil texture types—sand, sandy loam, loamy sand, and silty loam—by selecting four representative desert systems in the Hami region of Xinjiang, China. The objective was to elucidate the mechanisms through which soil texture may impact desert plant species diversity. The findings revealed that silty loam exhibited distinct characteristics in comparison to the other three sandy soil types. Despite its higher nutrient content, silty loam demonstrated the lowest vegetation diversity. The Shannon–Wiener index (H′), Simpson dominance index (C), Margalef richness index (D), and Pielou evenness index (Jsw) for silty loam were all lower compared to those for sand, sandy loam, and loamy sand. However, silty loam exhibited higher values in electrical conductivity (EC), urease activity (SUR), and nutrient content, including soil organic matter (SOM), ammonium nitrogen (NH⁴⁺-N), and available potassium (AK), than the other three soil textures. This study underscores the significant regulatory influence of soil texture on plant diversity in arid environments, offering new insights and practical foundations for the conservation and management of desert ecosystems. Full article

Optimizing water resource utilization is a critical challenge to meet the dramatic increase in food demand. Therefore, continuous studies to minimize water demand for plants are highly needed. This study aims to employ HYDRUS (2D/3D) software to simulate the effects of continuous and intermittent water flow on soil water distribution under a subsurface point source. The constant parameters included loamy sand soil, a water application time of 30 min, and an emitter discharge of 3.41 L/h. The variable parameters consisted are two pipe depths (25 cm and 35 cm), three ratios of ON:OFF times (1ON:1OFF, 1ON:3OFF, and 1ON:5OFF), and five water application cycles (WF1C, WF2C, WF3C, WF4C, and WF5C, with WF1C as for the continuous water flow). The results revealed that, in 30 min of water application, continuous water flow and ON:OFF ratios of 1ON:1OFF and 1ON:3OFF achieved maximum water retention in the vicinity of the emitter. In 60 min, increasing cycles enhanced retention for 1ON:1OFF and 1ON:3OFF, yet the 1ON:5OFF time ratio achieved the highest water content near the emitter. In 120 min, the 1ON:1OFF ratio showed an insignificant effect with cycle variations, but 1ON:3OFF and 1ON:5OFF exhibited increased retention. Similarly, in 180 min, 1ON:1OFF was unaffected by cycles, whereas 1ON:3OFF and 1ON:5OFF significantly improved retention. After 360 min, all treatments displayed equal water retention relative to the emitter position. Also, the results revealed that increasing water application cycles and ON:OFF time ratios lead to more holding soil water content, especially at soil levels of 20, 30, and 40 cm. These results affirm that positioning the emitters line at 25 cm enhances water retention more effectively than at 35 cm. Ultimately, statistical analysis confirmed that the combination of pipe depth, water application cycles, and ON:OFF ratios significantly affects the retention of soil water content in the vicinity of the emitter. Full article

The main goal of our work was to evaluate approaches for modeling lateral outflow from shallow unconfined aquifers in a one-dimensional model of vertical variably-saturated flow. The HYDRUS-1D model was modified by implementing formulas representing lateral flow in an aquifer, with linear or quadratic drainage functions describing the relationship between groundwater head and flux. The results obtained by the modified HYDRUS-1D model were compared to the reference simulations with HydroGeoSphere (HGS), with explicit representation of 2D flow in unsaturated and saturated zones in a vertical cross-section of a strip aquifer, including evapotranspiration and plant water uptake. Four series of simulations were conducted for sand and loamy sand soil profiles with deep (6 m) and shallow (2 m) water tables. The results indicate that both linear and quadratic drainage functions can effectively capture groundwater table fluctuations and soil water dynamics. HYDRUS-1D demonstrates notable accuracy in simulating transient fluctuations but shows higher variability near the surface. The study concludes that both quadratic and linear drainage boundary conditions can effectively represent horizontal aquifer flow in 1D models, enhancing the ability of such models to simulate groundwater table fluctuations. Full article

The application of soil organic amendments is a well-established approach to enhancing soil fertility; yet the effects of poultry feather hydrolysate (PFH) on temperate coarse-textured agricultural soils remain underexplored. A six-month microcosm experiment was conducted to determine the effects of PFH in different states (liquid or solid) and addition rates (none, low, or high; i.e., 0, 4, or 8 t dw ha⁻¹, respectively) on microbial activity, nutrient availability and retention, and organic matter (OM) stabilization in two coarse-textured soils (loamy sand or sandy loam). Sandy loam soil exhibited a stronger response to PFH application, supporting 20% higher microbial activity, 35% higher nutrient retention, and 89% higher OM content in soil aggregates compared to loamy sand soil, reflecting enhanced OM stabilization. Moreover, PFH in the liquid state demonstrated more prolonged microbial activity and more sustained release of nutrients compared to the solid state. Finally, at the end of incubation, the high addition rate of PFH significantly increased soil nutrient content by 106%, while the low addition rate limited the increase to 39%, both compared to the no addition rate. Overall, the results suggest that PFH, particularly in the liquid state and at the high addition rate, serves as an effective soil organic amendment, enhancing microbial activity and soil fertility while emphasizing the importance of soil texture in optimizing its application. Full article

Precision agriculture increasingly relies on real-time data from soil sensors to optimize irrigation and nutrient application. Soil moisture and electrical conductivity (EC) are key indicators in irrigation and fertigation systems, directly affecting water-use efficiency and nutrient delivery to crops. This study evaluates the performance of an IoT-based soil-monitoring system for real-time tracking of EC and soil moisture under varied fertigation conditions in both laboratory and field scenarios. The EC sensor showed strong agreement with laboratory YSI measurements (R² = 0.999), confirming its accuracy. Column experiments were conducted in three soil types (sand, sandy loam, and loamy sand) to assess the EC and soil moisture response to fertigation. Sand showed rapid infiltration and low retention, with EC peaking at 420 µS/cm and moisture 0.33 cm³/cm³, indicating high leaching risk. Sandy loam retained the most moisture (0.35 cm³/cm³) and showed the highest EC (550 µS/cm), while loamy sand exhibited intermediate behavior. Fertilizer-specific responses showed higher EC in Calcium Ammonium Nitrate (CAN)-treated soils, while Monoammonium Phosphate (MAP) showed lower, more stable EC due to limited phosphorus mobility. Field validation confirmed that the IoT system effectively captured irrigation and fertigation events through synchronized EC and moisture peaks. These findings highlight the efficacy of IoT-based sensor networks for continuous, high-resolution soil monitoring and their potential to support precision fertigation strategies, enhancing nutrient-use efficiency while minimizing environmental losses. Full article

Nutrient leaching from agricultural fields can degrade soil fertility and groundwater quality, especially in coarse-textured soils. Use of biochar, lime, and hydrogel in these soils can enhance nutrient and water use efficiencies, thus reducing water pollution, and aiding in sustainable agricultural production. Amending soils with biochar, lime, hydrogel, or their combinations may reduce leaching, but the effects of single versus combined amendments remain unclear. A three-year pot experiment under field conditions was conducted on a loamy sand soil to enhance water and nutrient retention capacity of this soil. Soil samples were mixed with all possible combinations of 1% biochar (B), l% lime (L), and 0.5% hydrogel (H), i.e., BL, BH, HL, and BHL. The amendments were arranged in a randomized complete block design with four blocks. The results showed that compared to control, amendments B, H, BH, HL, and BHL significantly decreased (p ≤ 0.05) nitrate-N leaching per unit biomass by 58–88%, and L, H, BH, BHL significantly reduced (p ≤ 0.05) orthophosphate-P leaching per unit biomass by 34–98%. Compared to the control, the marketable yield significantly increased (p ≤ 0.05) by 24–38% under BH, HL, and BHL in 2019, and by 17–52% under amendments B, L, H, BL, BH, HL, and BHL in 2020. These results were not seen in the first year due to soil conditioning for biochar and lime. Amendments H, BH, HL, and BHL show potential to improve water use efficiency, reduce nutrient leaching, and support sustainable crop production. Full article

Calocybe indica (milky mushroom), an edible mushroom with significant nutritional value, shows potential for cultivation in subtropical regions. Investigating the composition and diversity of the microbial community structure of the casing materials of C. indica is of great significance for understanding the stable yield of the mushroom. This study evaluated four casing materials—loamy soil (LS), loamy soil + cow dung (LS + CD), loamy soil + sand (LS + S), and plant ash (PA)—for their effects on mushroom yield, soil physicochemical properties, and microbial dynamics. The results demonstrated that LS + CD significantly enhanced the yield (2078.50 g) and fruiting body quality, with the shortest pinhead formation time (7.67 days) and superior morphological traits (e.g., cap diameter: 10.10 cm). Physicochemical analysis revealed LS + CD’s elevated moisture retention (19.7%), nutrient availability (e.g., available P: 59.63 mg/kg), and microbial biomass (C: 399.22 mg/kg), alongside a distinct microbial community dominated by Basidiomycota and Actinobacteria. Conversely, LS + S exhibited poor performance due to low water retention and nutrient deficiencies. Redundancy analysis highlighted strong correlations between soil nutrients (nitrogen, potassium, phosphorus) and microbial composition, with LS + CD fostering a microbiome conducive to mushroom growth. These findings underscore LS + CD as the optimal casing material for C. indica cultivation, improving both yield and soil health. Future studies should explore the functional roles of key microbes and refine organic amendments for sustainable practices. Full article

This study investigates how different types of microplastics (MPs)—fibers, glitter, plastic bags, and plastic bottles—influence heavy metal uptake in lettuce (Lactuca sativa L.), a commonly consumed leafy vegetable. A controlled eight-week pot experiment was conducted in a greenhouse using contaminated loamy sand soil (polluted with Cd, Pb, Cu, and other metals) collected from a smelter-impacted area. Microplastics were added at a concentration of 70–80 mg/kg, and lettuce seedlings were grown under phytotron conditions (22 ± 2 °C, 60 ± 5% RH, 16 h light/8 h dark) without fertilizers or external contaminants. Plant roots and shoots were harvested, and heavy metals were analyzed via MP-AES and ICP-MS. The results showed that MPs altered heavy metal mobility, bioavailability, and plant uptake. Copper accumulation in leaves decreased substantially across MP treatments, from 80.84 mg/kg in the control to 26.35 mg/kg (glitter), whereas lead and cadmium concentrations increased significantly in roots under fiber and glitter exposure (Pb increased from 12.13 mg/kg to 33.57 mg/kg and Cd from 1.70 mg/kg to 2.05 mg/kg in fiber treatment). Cobalt accumulation in leaves increased under the plastic bag treatment, indicating MP-specific metal interactions. Root growth was also affected, with fibers promoting elongation and plastic bottles restricting it. Sequential extraction revealed that MPs modified metal partitioning in soil, with Pb and Ni more strongly retained in stable fractions under some treatments. Observed trends in soil pH and organic matter content were associated with changes in metal mobility, highlighting the potential role of soil properties in mediating microplastic–metal interactions. These findings highlight the role of MPs as mediators of heavy metal transport in crops and underscore the need for clear regulatory guidelines that limit microplastic contamination in agricultural soils and promote routine monitoring to safeguard food safety and crop health. Full article

Livestock production systems can negatively affect soil structure, resulting in negative changes in physical–hydraulic properties, compromising soil functioning and productivity. This research aimed to evaluate the effects of rotational silvopastoral systems on soil physical–hydraulic functioning in their second year of implementation. The study was performed under Oxisol soil with a loamy sand texture in Southeast Brazil. We considered four grazing systems: an intensive silvopastoral system with Panicum maximum in consortium with Leucaena leucocephala (ISPS + L), an intensive silvopastoral system with Panicum maximum in consortium with Tithonia diversifolia (ISPS + T), an silvopastoral system with Panicum maximum (SPS) with tree row (TRs), and open pasture under a rotational grazing system with Panicum maximum (OP). The treatments ISPS + L, ISPS + T, and SPS had tree rows (TRs) every 20 m composed of Khaya ivorenses, Leucaena leucocephala, Eucalyptus urograndis, Acacia mangium, and Gliricidia sepium. Nine physical–hydraulic indicators were evaluated in the first 0.40 m of depth: bulk density (Bd), total porosity (TP), macroporosity (MaP), microporosity (MiP), field capacity (FC), permanent wilting point (PWP), available water content (AWC), total soil aeration capacity (ACt), and S-index. The soil physical–hydraulic properties were sensitive to the effects of the livestock systems. The use of silvopastoral systems in consortium with grass (ISPS + L and ISPS + T) allowed for better soil water retention, resulting in higher FC and AWC than the OP, SPS, and TR. The indicators Bd, ACt, MaP, FC, MiP, and S-index presented the greatest variance; however, FC, ACt, MaP, and MiP enabled the greatest differentiation among systems. Therefore, these properties are important in studies on soil physical quality since they provide information about the soil porous status and its ability to retain water and exchange soil air and gases. Therefore, enhancing the physical–hydraulic attributes of the soil in silvopastoral systems with shrub species is crucial for ensuring long-term productive sustainability and strengthening environmental resilience against future climate challenges. Full article

Comparison of soil water sensors for irrigation scheduling requires an accurate reference measurement. An Acclima TDR-310H soil water content sensor was calibrated and validated for sand, loamy sand, clay loam, sandy clay loam, and sandy loam soils. In 2021, sensor readings and soil samples were collected in the same sensor volume at depths of 15 and 46 cm at three irrigated field sites with five stations each. Gravimetric water content, bulk density, and volumetric water content (θ_v) were determined in the lab. The root mean square error was 0.032 cm³ cm⁻³, which was within acceptable limits. The sensor underestimated θ_v with a mean bias error of −0.025 cm³ cm⁻³. The linear field calibration equation was θ_v-Sample = 0.9498 θ_v-TDR + 0.0357 with R² = 0.8984. t-tests showed that the 95% confidence intervals (CIs) were 0.82 < slope < 1.08 and 0.0072 < intercept < 0.0642. Since the field calibration result was different from the factory calibration (intercept CI not straddling 0), use of the field calibration is recommended. A validation dataset collected in 2023 confirmed the calibration equation. The calibrated sensor can be used to evaluate other θ_v sensors for irrigation scheduling in the soil types in this study. Full article

To mitigate the loss of surface runoff and deep percolation in the water-scarce area and enhance the utilization of rainfall resources, this study adaptively determines the soil water content threshold triggering such losses by incorporating rainfall intensity (RI) and soil properties (SP) based on the model predictive control (MPC) framework. These thresholds then serve as the target soil water content before rainfall, and a model predictive control incorporating RI and SP (RISPMPC) irrigation decision-making is proposed. We conducted irrigation simulation experiments in Ya’an City, Sichuan Province, across four RI levels and six soil texture types. The results were compared with those obtained from conventional model predictive control (CMPC), rule-based closed-loop irrigation decision (RBC), and a newly developed zone-based model predictive control (ZMPC). Results demonstrate that RISPMPC enhances the utilization of rainfall resources across different scenarios. In soils with strong infiltration capabilities, such as loamy sand, loam, and clay loam, RISPMPC reduces irrigation water use by 26%, 5%, and 3% compared to RBC, CMPC, and ZMPC, respectively. In contrast, for soils with poor infiltration capabilities, including silty soil, clay A, and clay B, RISPMPC’s water-saving efficiency strongly correlates with rainfall intensity levels, achieving maximum savings of 61%, 36%, and 34% compared to the same three methods. Furthermore, in all cases, RISPMPC demonstrates the highest maximum effective rainfall utilization rate (MERU). As soil infiltration capability decreases and rainfall intensity increases, the MERU gap between RISPMPC and the other three methods widens significantly, underscoring RISPMPC’s robustness in environments where rainwater utilization is challenging. Therefore, RISPMPC can improve the utilization efficiency of rainwater resources and effectively alleviate agricultural water scarcity issues. Full article

This research investigates the impact of compost particle size, compost additives, and application rate on the physical properties of loamy sand soil, particularly focusing on water retention characteristics. Compost, enriched with additives like zeolite, biochar, and diatomite, was applied to soil in different rates: 1%, 2%, and 4%. Compost particles were divided into three particle size classes: 0–500 µm, 500–1000 µm, and 1000–2000 µm. The study revealed significant effects of compost on soil physical quality, including bulk density, porosity, and water retention. Zeolite-enriched compost showed the most pronounced improvements in soil water retention by modifying pore diameter. However, the effectiveness of compost additives varied depending on the type and rate of application. Compost with zeolite resulted in a decrease in the volume of large soil pores with diameters of 50–500 µm and above 500 µm. This resulted in higher water retention related to mesopores. Larger compost particles (1.0–2.0 mm) exhibited superior effects on soil physical quality compared to smaller particles (<1.0 mm), although finer particles (0.5–1.0 mm) were associated with higher water repellency. Compost with diatomite resulted in higher water repellency than other compost types. The findings underscore the importance of considering compost particle size, component type, and application rate to optimize soil hydraulic characteristics, particularly in agricultural practices where water management is crucial. Full article

This study had two primary objectives: (1) to determine relative differences in soil infiltration capacity between native grasslands and thicketized oak woodlands and (2) to compare the effectiveness of three infiltration measurement techniques—rainfall simulation, an automated Simplified Steady Beerkan Infiltration (SSBI) method, and the Saturo dual-head infiltrometer. The study was conducted at three sites with clay, loamy sand, and sandy soils. Rainfall simulation captured significant infiltration differences between vegetation covers at all three sites, while SSBI did so at two sites, and Saturo failed to detect significant differences. Consistent with past studies, rainfall simulation results showed significantly higher infiltration capacity in thicketized woodlands compared to adjacent grasslands, with mean infiltration capacity an order of magnitude greater in clay soils (67 mm h⁻¹ vs. 7.5 mm h⁻¹) and more than twice as high in sandy (144.5 mm h⁻¹ vs. 69 mm h⁻¹) and loamy sand (106 mm h⁻¹ vs. 49 mm h⁻¹) soils. Across sites, rainfall simulation and SSBI showed strong positive correlations between infiltration capacity and dead biomass (R² = 0.74 and 0.46, respectively; p < 0.001 for both), as well as significant negative correlations with live biomass and bulk density. In contrast, the Saturo method exhibited higher variability, overestimating infiltration capacity by an average of 34.3 mm h⁻¹ compared to rainfall simulation, and did not capture significant relationships with biomass or bulk density. Our findings have twofold importance: first, they demonstrate that thicketization of oak savannahs results in higher soil infiltration capacity; and second, they show that for determining soil infiltration capacity, the SSBI methodology is an accurate and practical alternative to the labor-intensive rainfall simulation. Full article

The ability to track moisture content using soil moisture sensors in green stormwater infrastructure (GSI) systems allows us to understand the system’s water management capacity and recovery. Soil moisture sensors have been used to quantify infiltration and evapotranspiration in GSI practices both preceding, during, and following storm events. Although useful, soil-specific calibration is often needed for soil moisture sensors, as small measurement variations can result in misinterpretation of the water budget and associated GSI performance. The purpose of this research is to quantify the uncertainties that cause discrepancies between default (factory general) sensor soil moisture measurements versus calibrated sensor soil moisture measurements within a subsurface layer of GSI systems. The study uses time domain reflectometry soil moisture sensors based on the ambient soil’s dielectric properties under different soil setups in the laboratory and field. The default ‘loam’ calibration was compared to soil-specific (loamy sand) calibrations developed based on laboratory and GSI field data. The soil-specific calibration equations used a correlation between dielectric properties (real dielectric: ε_r, and apparent dielectric: K_a) and the volumetric water content from gravimetric samples. A paired t-test was conducted to understand any statistical significance within the datasets. Between laboratory and field calibrations, it was found that field calibration was preferred, as there was less variation in the factory general soil moisture reading compared to gravimetric soil moisture tests. Real dielectric permittivity (ε_r) and apparent permittivity (K_a) were explored as calibration options and were found to have very similar calibrations, with the largest differences at saturation. The ε_r produced a 6% difference while the K_a calibration produced a 3% difference in soil moisture measurement at saturation. K_a was chosen over ε_r as it provided an adequate representation of the soil and is more widely used in soil sensor technology. With the implemented field calibration, the average desaturation time of the GSI was faster by an hour, and the recovery time was quicker by a day. GSI recovery typically takes place within 1–4 days, such that an extension of a day in recovery could result in the conclusion that the system is underperforming, rather than it being the result of a limitation of the soil moisture sensors’ default calibrations. Full article

This study examines the potential of natural biostimulants to mitigate environmental stress and enhance growth, yield, and quality in eggplant (Solanum melongena L., cv. Black Beauty) grown in loamy sand soil. Eggplants were treated with foliar applications of ascorbic acid (AA) at 300 mg/L, chitosan (Ch) at 200 mg/L, and moringa oil (MO) at 1000 mg/L as natural biostimulants. Results indicated significant increases in plant height, branch number, leaf chlorophyll content, fruit count, and total yield per feddan (0.42 ha) with the AA, Ch, and MO treatments compared to untreated controls. Treated plants also displayed enhanced fruit characteristics, including increased weight, diameter, length, and size. Biochemical analyses revealed elevated levels of fruit dry matter, ascorbic acid content, total phenols, flavonoids, and antioxidant activity. Untreated plants, in contrast, showed significantly lower values across all measured parameters, indicating higher susceptibility to environmental stressors and reduced growth and fruit quality. These findings underscore the effectiveness of AA, Ch, and MO as biostimulants in enhancing eggplant growth, yield, and fruit quality under loamy sand conditions. Furthermore, the use of biostimulants could be extended to other crops, offering a sustainable approach to improving food security and sustainability in agricultural practices. Full article