Soil Depth Research Articles

Leaching and vertical distribution of Fe and Zn citrate nanoparticles in Indian red soil

This research aims to address common constraints in the effective utilization of plant nutrients in soil, such as fixation, mobility, leaching, and reactions with soil colloids. To mitigate these issues, Fe and Zn citrate nanoparticles were synthesized and applied as nanochelators in a reconstructed soil profile column. We evaluated the mobility, release, and leaching behaviors of these nanoparticles. Results revealed that, no leaching of Fe and Zn citrate nanoparticles occurred even after a 90-day incubation. The release profiles exhibited a peak at 60 and 90 days for Fe and Zn respectively. In the mobility studies, Fe and Zn availability was highest in the 0–15 cm soil depth. Fe citrate and Zn citrate nanoparticles demonstrated the highest availability at 264.7 mg/kg and 86.26 mg/kg of soil, respectively as compared with commercial samples. The superior performance of Fe and Zn citrate nanoparticles was observed in terms of reduced leaching and improved accessibility, indicating their potential as efficient and environmentally-friendly plant nutrient sources. The study concludes that Fe and Zn citrate nanoparticles are stable nutrient sources that can enhance plant use efficiency with minimal environmental impact.

Differential responses of soil CO2 dynamics along soil depth to rainfall patterns in the Chinese Loess Plateau

Soil surface carbon dioxide (CO2) efflux not only originates from topsoils, but also significantly involves contributions from deeper soil layers. Soil surface CO2 efflux significantly fluctuated with rainfall patterns in arid and semiarid regions. However, how soil CO2 dynamics respond at different soil depths to varying rainfall patterns remains largely unclear. To address this gap, we continuously monitored soil CO2 concentrations, temperature, and moisture content at 10 cm, 50 cm, and 100 cm depths in situ under cropland and orchards located in the semiarid Loess Plateau over a full year. Rainfall events were meticulously recorded, categorizing them into light (<10 mm), moderate (10 mm–40 mm), and heavy (>40 mm) to discern their impact on soil CO2 dynamics. Specifically, soil CO2 flux was not affected during light rainfall. Moderate and heavy rainfall decreased soil CO2 flux at 0–10 cm by an average of 70% and 83%, respectively. This decrease was associated with reduced gas diffusivity across rainfall patterns. For instance, heavy rainfall reduced gas diffusivity by an average of 83% and 53% at 10 cm and 50 cm soil depths, respectively. Furthermore, soil CO2 concentrations slightly dropped as soil temperature decreased at 10 cm depth during light rainfall. Soil CO2 concentrations at 10 cm and 50 cm depths initially decreased by up to 15% and subsequently increasing by up to 52% during moderate and heavy rainfall. This response was likely influenced by temperature reductions and subsequent rises in moisture content, with a hysteretic response of soil CO2 concentrations to temperature. The rapid increase in soil CO2 concentrations was mainly due to a substantial decrease in gas diffusivity. Notably, heavy rainfall induced a delayed increase in soil moisture content at 50 cm depth and a significant decrease in CO2 concentration by 16% at 100 cm depth. A substantial decrease in soil CO2 concentrations in deep soil layers was primarily related to decreased soil temperature. Additionally, the observed soil CO2 dynamics were partly attributed to biotic factors (microbial biomass carbon and root density) mainly on cropland, but mainly abiotic factors (soil organic carbon and bulk density) under orchards. Overall, these results suggest that reduced gas diffusivity triggered by increased soil moisture content in topsoils and weakened biological processes caused by decreased soil temperature in deep soils typically drive the differential responses of soil CO2 dynamics to rainfall patterns.

Fate of per- and polyfluoroalkyl substances at a 40-year dedicated municipal biosolids land disposal site

The fate of per- and polyfluoroalkyl substances (PFAS) was evaluated at a site where municipal biosolids have been applied annually for 38 years as a waste management strategy. Soil cores (1.8 m in 30-cm sections), groundwater from four wells, and biosolids applied in 2022 were analyzed for PFAS (54 targeted, 17 semi-quantified) using liquid chromatography high resolution mass spectrometry including suspect screening. Total PFAS concentrations decreased with soil depth from 1700 ng/g to 2.06 ng/g. PFAS distribution in 2022 biosolids were 60 mol% perfluoroalkyl acid (PFAA) precursors and intermediates. The surface soil was dominated by long-chain PFAAs (67–76 mol%) reflecting precursor degradation after biosolids application. Presence of semi-quantified intermediates further reflects precursor degradation in surface soil. Long-chain PFAAs diminished with depth while short-chain PFAAs increased with up to 98 and 96 mol% short-chain PFAAs in the bottom depth and groundwater, respectively. PFAS distribution with depth is consistent with chain-length dependent sorption-impacted transport and the high organic carbon content of the surface soil (15.2 % OC) which subsequently decreased with depth (~2–3 % OC at >60 cm). High organic carbon content in the upper horizon is likely from decades of high biosolids application rates, which contributed to minimizing leaching of long-chain PFAS. While the well within the dedicated land disposal is not drinking water, for comparison only, PFAS concentrations in this well only marginally exceeded the EU drinking water directive for total PFAS and a few individual short-chain PFAS, but did exceed tenfold, the USEPA drinking water standard for PFOA.

Sources and Sinks of N in Ecosystem Solutions Along the Water Path Through a Tropical Montane Forest in Ecuador Assessed With δ15N Values of Total Dissolved Nitrogen

AbstractThe globally increasing reactive N richness affects even remote ecosystems such as the tropical montane forests in Ecuador. We tested whether the δ15N values of total dissolved N (TDN), measured directly in solution with a TOC‐IRMS, can be used to help elucidate N sources and sinks along the water path and thus might be suitable for ecosystem monitoring. From 2013 to 2016, the δ15N values of TDN in bulk deposition showed the most pronounced temporal variation of all ecosystem solutions (δ15N values: 1.9–5.9‰). In throughfall (TF), TDN was on average 15N‐depleted (−1.8 ± s.d. 0.4‰) relative to rainfall (3.4 ± 0.9‰), resulting from net retention of isotopically heavy N, mainly as NH4+. Simultaneously, N‐isotopically light NO3−‐N and dissolved organic nitrogen (DON) with a δ15N value between NO3−‐N and NH4+‐N were leached from the canopy (leaves: −3.5 ± 0.5‰). The increasing δ15N values in the order, TF &lt; stemflow (SF, 0.1 ± 0.6‰)&lt; litter leachate (LL, 1.3 ± 0.7‰) concurred with an increasing DON contribution to TDN reflecting the δ15N value of the organic layer (1.9 ± 0.9‰). The lower δ15N value of the mineral soil solution at the 0.15 m soil depth (SS15, −1.5 ± 0.3‰) than in LL can be explained by the retention of DON and NH4+ and the addition of NO3− from mineralization and nitrification. The increasing δ15N values in the order, SS15 &lt; SS30 (−0.6 ± 0.2‰) &lt; streamflow (ST, 0.5 ± 0.6‰) suggested gaseous N losses because of increasing denitrification. There was no seasonality of the δ15N values. Our results demonstrate that the δ15N values of TDN in ecosystem solutions help identify N sources and sinks in forest ecosystems.

Depth Wise Distribution of Soil Physico-Chemical Properties and Nutrients Across a Toposequence Located at KVK Farm, Sakhigopal, Odisha, India

This study aims to identify soil-related constraints for crop production and provide insights for soil management by analyzing soil profiles across different topographic positions (upland, medium land, and lowland) at KVK farm, Sakhigopal, Puri located in the East and Southeastern Coastal Plain Agro-Climatic Zone of Odisha. The profiles were evaluated for key physico-chemical properties and nutrient contents, revealing significant variations influenced by topography. The results showed that the soil's physical and chemical properties and available nutrient status showed distinct variations among the pedons. Among soil physical properties, the sand percentage, bulk density, and particle density increased with soil depth. Whereas, the clay percentage, total porosity, and water-holding capacity decreased with soil depth. Soil pH ranged from 6.32 to 7.50 and the electrical conductivity was recorded below 1 dSm-1. The organic carbon content ranged from 8.6 to 10.3 g kg-1. In general, soil pH, base saturation, and exchangeable cations increased with soil depth. On the other hand, soil organic carbon content and exchangeable acidity decreased with soil depth. Available nitrogen, phosphorus, potassium, and sulphur contents decreased with soil depth. However, in general, their concentrations increased along the slope (towards low land), which may be attributed to increased levels of organic carbon and clay contents in the lower topographic positions owing to high moisture content and higher cropping intensity. The findings of this study provide valuable insights regarding soil property characterisation across a transect for sustainable land use planning.

Accumulation of Cd and Pb in soils irrigated with sewage and non-sewage water in Prayagraj, India

Unmanaged agricultural fields and the extended usage of sewage irrigation water can raise the concentration of heavy metals (Cd and Pb) in the soil, turning it into barren soil. The study was conducted during 2022-23 at four sewage and non-sewage irrigated sites in Prayagraj namely Naini, Baxibandh, Rasulabad and Draupadi Ghat. The representative soil samples were taken at depths of 0-15, 15-30, 30-45 and 45-60 cm. Di-acid mixture method was used for the estimation of heavy metals (Cd and Pb) in the soil sample by AAS (Atomic Absorption Spectrophotometer) (AAnalyst600, Perkin Elmer Inc., MA, USA). Contamination factor (CF) and enrichment factor % (EF) of different sites showed various results which fulfill the basic criteria of present and future prospective of research. The highest concentration of Cd and Pb was found in the surface layer (0-15 cm) of sewage and non-sewage irrigated sites at Naini i.e., Cd (4.46±0.42 and 1.05±0.08 mg/kg) and Pb (6.53±0.62 and 1.18±0.12 mg/kg) respectively. The lowest concentration of Cd and Pb was found in the sub-surface layer (45-60 cm) of sewage and non-sewage irrigated sites at Draupadi Ghat i.e., Cd (1.02±0.09 and 0.16±0.01 mg/kg) and Pb (1.68±0.12 and 0.18±0.01 mg/kg) respectively. The concentration of heavy metals cadmium (Cd) and lead (Pb) declined with soil profile depth in both sewage and non-sewage irrigated soils. The long-term persistence of heavy metal contamination in soil can lead to severe issues; therefore, regular monitoring of sewage-irrigated soils is necessary to minimize heavy metal pollution.

Centrifuge tests for earthquake response of shallow soil with locally raised bedrock

ABSTRACT Centrifuge tests were performed to study the dynamic properties of shallow soil with locally raised bedrock (i.e. variable soil depth). The test parameter was the slope of bedrock: 0° (S0), 35° (S35), and 45° (S45). In each test, accelerations were measured along the soil depth, and the results of acceleration, displacement, Fourier transform, and response spectrum were compared. Based on the results, the transfer function (TF), the ratio of response spectrum (RRS), and the site period were estimated. The ground motion and site period of specimens with raised bedrock were smaller than those of the specimen without raised bedrock (i.e. with deeper soil). Further, parametric studies using 2-dimensional finite element (FE) analysis were performed to investigate the effect of design parameters on the response of shallow soil with variable soil depths. For design parameters, the length of raised bedrock and the length of foundation slab were considered. Parametric study results indicated that when the shallow soil region is wide, the results are similar to those of a 1-dimensional soil column. However, when the shallow soil region is narrow, the 2-dimensional response is smaller than the 1-dimensional soil column response. This was also observed in the actual site model.

Spatio-Temporal Dynamics of Soil Penetration Resistance Depending on Different Conservation Tillage Systems

As conservation tillage becomes one of the foundations of sustainable crop production, important questions arise about its value, which needs to be defined and evaluated. One of the most important indicators of soil compaction is penetration resistance (PR), which comes as a short-term response to the state of soil physics. The objective of this work is to compare different tillage treatments (TT) on soil compaction on silty clay loam Stagnosol and silt Gleysol in the continental part of Croatia. The research included three tillage treatments: ST—conventional tillage, CTD—deep conservation tillage, and CTS—shallow conservation tillage. PR was determined on each soil depth of 5 cm up to 80 cm, and measuring was provided on two measuring dates. The obtained results showed a higher influence of the year factor than TT. In the upper layers (up to 35 cm), PR values between TT were with significant differences, but in most cases below root-limiting critical values, while in deeper soil layers (35–80 cm), we found that penetration values on each tillage treatment begin to stabilize and smooth out in most cases, with similar dynamics on both soil types and measurement dates. In most of the cases, the highest PR was measured for conservation treatments in wetter soil conditions.

Effect of altitudes and aspects on carbon sequestration potential of Quercus floribunda forests of Garhwal Himalayas

The forests are major resources for carbon sequestration and help to mitigate the adverse effect of atmospheric carbon and reduce global warming. The present study was conducted to estimate the carbon sequestration potential of the Quercus floribunda forests at two different aspects and three altitudes. Ten quadrates of 10 × 10 m size were laid out in each forest for the estimation of stand density, tree biomass, and soil samples were collected from each quadrate. Q. floribunda was the dominating tree at studied altitudes and aspects with the IVI values of 161.14 and 124.96 in the southern aspect and northern aspects, respectively. the highest values of above-ground biomass density (AGBD), below-ground biomass density (BGBD), total biomass density (TBD), and total carbon density (TCD) was recorded at the upper elevation (2500–2700 m) of southern and northern aspects. In the southern aspect values of AGBD (476.67 < 575.67 Mg/ha), BGBD (124.8 < 148.9 Mg/ha), TBD (601.53 < 724 Mg/ha), TCD (300.83 < 362.03 Mg/ha) were higher than northern aspect. The values of AGBD, BGBD, TBD, and TCD were reported maximum (638 Mg/ha, 163.1 Mg/ha, 800.5 Mg/ha, and 400.35 Mg/ha; respectively) in the upper elevation. Soil organic carbon (SOC), soil organic matter (SOM), and soil organic carbon stock (SOCS) decreased with increasing altitudes and depths which were found higher in the southern aspect. Bulk density (BD) and P increased with altitudes and depth however bulk density was equal (1.29 g cc-1) in both aspects whereas P was also found higher (31.43 kg/ha) in the southern aspect. Highest available nitrogen (398 kg/ha) was recorded in the northern aspect at middle altitude. The available potassium was highest in the northern aspect. At lower altitudes, available potassium ranges between 246–615 kg/ha. Soil pH was found slightly acidic in all the sites ranging from 4.91 to 5.74 in different soil depths. Dehydrogenase activity was ranged between 1.35 and 8.74 µg/g/h from lower to upper soil depth and decreased with an increase in soil depths and increased with altitudes, whereas found highest in the southern aspect. The present study suggested that tree density, tree biomass, carbon sequestration potential, and soil health in Q. floribunda forests were substantially influenced by the altitude as well as the aspect. These findings contribute valuable insights for climate change mitigation and forest management strategies in the study region.

Changes in soil microbial community and function across stand age of Cryptomeria japonica var. sinensis plantations in subtropical China

Microbial communities are important influencing factors in soil biogeochemical cycling. Differences in stand age can affect microbial communities and functions by altering soil biochemical characteristics. Studying the changes in soil microbial communities and functions at different ages of Cryptomeria japonica var. sinensis can provide a theoretical basis for the scientific management of plantations. Therefore, we collected soil samples from different soil depths from 7- (7a), 13- (13a), 24- (24a), 33- (33a), and 53-year (53a) C. japonica var. sinensis plantations, to assess the differences in soil biochemical characteristics, soil bacterial and fungal communities, soil enzyme activity, and soil respiration rate. Results showed that as the stand age increases, the ACE and Shannon indices of fungal communities showed an initial increase followed by a decrease, whereas the Chao 1 index showed an increasing trend. The ACE and Shannon indices of bacterial communities did not change with stand age, but the Chao1 index decreased with an increase in stand age. In addition, the fungal ACE and Chao1 indices and bacterial Shannon index were higher at the 0–15 cm depth than at the 15–30 cm depth. Soil microbial community composition varied with stand age and soil depth, including Proteobacteria and Unclassified_k_Fungi relative abundances, and their functional groups' (nitrogen cycling-related bacteria, saprophytic fungi, pathogens, and ectomycorrhizal fungi) relative abundances. In addition, stand age will indirectly affect soil microbial function by influencing soil biochemical characteristics and microbial communities at the 0–15 cm depth, whereas at the 15–30 cm depth, there is no direct or indirect impact on the above indicators. In summary, significant variations exist in soil microbial communities and their functions across stand ages, and these differences will further vary between soil depths. Our research contributes to a better understanding of the impact of different ages of afforestation on soil biogeochemical cycling, providing valuable microbial information for the sustainable management of C. japonica var. sinensis forests in the future.

Nutrient Potential Mapping of Soils for Tea Plants Through Laboratory and Geostatistical Approaches

&lt;p&gt;The assessment of nutrient potential is crucial for enhancing tea production and achieving sustainable agricultural goals. Thus, the present study was carried out to assess and map the soil nutrient potential for tea plants through laboratory and geostatistical methods. A total of 74 random soil samples with 3 replications were collected from 0 to 9 cm (topsoil) and 9 to 18 cm (subsoil) depths from Oodaleah Tea Garden (OTG) which belongs to Fatikchhari Upazila of Chattogram District in Bangladesh. All the laboratory analyses were done following standard procedures and maps of individual soil indices were prepared through the Inverse Distance Weighted (IDW) interpolation technique using ArcGIS 10.7 software. The integration of maps for nutrient potential was performed following the Analytic Hierarchy Process (AHP). The mean concentrations of organic matter (OM), total nitrogen (TN), available phosphorus (AvP), available potassium (AvK), and available calcium (AvCa) were found higher at 0 to 9 cm compared to 9 to 18 cm soil depth with significant (&lt;em&gt;p&lt;/em&gt; &amp;lt; 0.05) difference among the sampling sites. The maps of individual soil parameters revealed distinct spatial differences at 0 to 9 cm and 9 to 18 cm soil depths. The total study area covered 5.99 km&lt;sup&gt;2&lt;/sup&gt;. Integrated nutrient potential mapping showed that moderately suitable (44.15%) accounted for the largest proportion, followed by highly suitable (26.03%), generally suitable (21.67%), marginally suitable (7.06%), and unsuitable area (1.08%) of the tea plantation suitability evaluation. The integrated map of nutrient potential will aid in better management of the tea soils.&lt;/p&gt;

Sulphur Fractions, Distribution, and Connections with Soil Attributes in the Gopalpur and Ishwardi Soil Series of Bangladesh

The deficiency of soil sulfur (S) is a prevalent issue in Bangladesh soils, posing a significant obstacle to enhancing crop yield and overall productivity. This study aimed to evaluate the distribution of different sulfur fractions across various soil depths in the Gopalpur and Ishwardi soil series, along with their relationships with other soil parameters. In both soil series, the sulfur fractions were ordered as follows: organic &gt; adsorbed &gt; available forms, with organic sulfur being the most abundant. Additionally, soil attributes such as pH, organic carbon, texture, and EC were assessed to understand their relationships with sulphur fractions. Results indicate significant variations in sulphur distribution between the two soils series, with organic sulphur dominating in Gopalpur soils and sulphate-sulphur prevailing in Ishwardi soils. Correlation analysis reveals strong associations between sulphur fractions and soil attributes, highlighting the influence of soil properties on sulphur dynamics. These findings provide valuable insights into sulphur cycling in agricultural soils of Bangladesh and underscore the importance of soil management practices for optimizing sulphur availability and crop productivity.

Effects of Deficit-Regulated Irrigation on Root-Growth Dynamics and Water-Use Efficiency of Winter Wheat in a Semi-Arid Area

Water management is critical for wheat production under extreme drought conditions, and the mechanisms by which root dynamics and soil water utilization affect wheat yield are uncertain. This study was conducted in 2023–2024 under a mesophilic semi-arid climate with a two-factor partitioned experimental design, aiming to assess the response of different irrigation amounts in winter wheat crops on root growth and development, soil water utilization, and yields in different soil horizons. The results showed that variety and irrigation volume had significant effects on the spatial and temporal distribution of root and yield components, with irrigation volume having the greatest effect on yield. Compared with CK, deficit-regulated irrigation significantly promoted root penetration to deeper layers and delayed root senescence. DRWD, RLD, RSA, and RV decreased gradually with increasing soil depth, and the peaks of RLD, RSA, and RV appeared at the tassel to flowering stage, respectively; and under deficit-regulated irrigation, the contribution of the A2W4 treatment to stable yield was greater. Therefore, A2W4 is an effective water-saving irrigation method to improve grain yield and water-use efficiency under deficit-regulated irrigation.

Performance Evaluation of Woybo Irrigation Scheme: Wolaita Zone, Southern Ethiopia

Performance evaluation of irrigation scheme is vital for realizing the present status and identifying the area for improvement. The study was conducted in Woybo irrigation scheme which is located in Boloso Sore district, Wolaita zone, Southern Ethiopia. This study was aimed to evaluate the performance of Woybo irrigation scheme with internal performance indicators. A total of nine demonstrating farmers&amp;apos; fields were selected from three canal reaches (head, middle, and tail) through purposive sampling. Primary and secondary data were collected, recorded, and analyzed. To measure the water applied to each experimental field, Parshall flume was installed, and soil samples were taken to determine soil texture, field capacity, permanent wilting point, and soil moisture content before and after each irrigation event at regular soil depth intervals. The results revealed that the mean conveyance efficiency was 60.85% and the application efficiency was 48.53%. Water distribution uniformity, deep percolation, and storage efficiencies were 84.56%, 51.47%, and 85.22%, respectively. However, the overall irrigation efficiency was found to be 29.53%, which was poorly performed due to inadequate water application, ineffective field water management, and low efficiency in water delivery systems. The main factors contributing to the poor water delivery performance included failures in water regulating gates, leakages, and siltation of canals. To address these problems, recommendations are made such as improvements in water application techniques should be implemented, through proper irrigation scheduling, water conservation practices, surge irrigation techniques, and providing extension support, training, and experience sharing. Additionally, maintenance and lining of earthen canals are necessary, along with the replacement and repair of leakages and broken water regulating and controlling structures. These measures can help to upgrade water delivery efficiency and improve the overall performance of the irrigation scheme.

Stabilization and Remediation of Arsenic-Contaminated Soil: Fly Ash-Based Technology for Industrial Site Restoration

Arsenic contamination of various environmental components poses a serious threat to human and animal health. Soil As contamination is particularly hazardous, as soil is a vital pathway to the food chain. We conducted experiments on soil from a typical pharmaceutical and chemical industry relocation site in Hubei Province, focusing on modification using fly ash through mechanical and chemical mechanisms. We subjected varying proportions of lime, ferrous sulfate, and fly ash to mechanical ball milling and used these mixtures to perform remediation of arsenic-contaminated soil and site restoration. Our findings are as follows: in soil culture experiments, the As stabilization efficiency reached 90% within 90 days with ferrous salt-modified fly ash. In actual site restoration, As-stabilization efficiency exceeded 95% across different soil depths within 30 days, demonstrating significant stabilization effects. Optimal modified dosages were determined as 2% ferrous sulfate and 2% fly ash. After stabilization, As in the soil primarily existed in amorphous iron-aluminum oxide-bound (F3) and crystalline iron-aluminum oxide-bound (F3 + F4) and residual (F5) states. Fluctuations in the moisture content and pH mainly activated F3 and F4, transitioning them into exchangeable (F1) and surface-adsorbed (F2) states. Arsenic leaching was predominantly associated with the F1 form. Fly ash-based restoration technology demonstrates promising capabilities in waste treatment and pollution control, offering significant potential for widespread application.

Growth Performance of Sabia Grass Irrigated by Drippers Installed in Subsurface

Studies to improve the use of subsurface drippers in pasture formation are needed. Therefore, the objective of this study was to evaluate the germination and emergence of Sabia grass as a function of drippers installed at different depths. The study was conducted in pots in Viçosa, Minas Gerais State, Brazil. The experiment was conducted using a completely randomized design with four replicates. The experimental layout featured split plots over time, where the main plots consisted of three cultivation cycles and the subplots represented various dripper installation depths. The three sowing dates were 26 March, 12 April, and 29 April 2022. Drip tapes were installed at seven different depths: 0 (superficial), 5, 10, 15, 20, 25, and 30 cm. The results showed that the reduction in water potential, associated with increased temperature, resulted in lower performance of Sabia grass seeds. Seed germination and parameters related to germination speed were negatively impacted by the increase in dripper installation depth, with a 30–40% reduction in germination speed observed at depths greater than 15 cm. Drippers installed at 15–20 cm depth in clayey soil were ideal, providing a balance between reducing soil water evaporation and maintaining seedling emergence rates. Compared to surface installation, this depth improved seed performance by up to 25%, while enhancing operability and minimizing water loss. It is recommended to install drippers at a depth of 15–20 cm in subsurface drip irrigation systems in clayey soil areas to achieve benefits such as decreased soil water evaporation and improved operability compared to surface systems.

Assessing the change in soil water deficit characteristics from grassland to forestland on the Loess Plateau

Soil moisture is an important factor that affects terrestrial ecosystems and biological growth and development, and water deficit is one of the major environmental factors threatening vegetation restoration on the Loess Plateau. The purpose was to identify the change in the soil water deficit characteristics from grassland to forestland on the Loess Plateau. In this study, we measured the soil water storage and deficit in abandoned grassland, shrubland, pioneer forestland and climax forestland along with vegetation succession in situ monitor. The results showed that the soil water content and the soil water storage with natural vegetation recovery from the abandoned grassland to shrubland and forestland showed a gradual declining trend. While on the contrary, the soil water deficit was increasing during succession, it was more severe in the deep soil than in the shallow soil layers. And the soil water deficit in July and September of the rainy season as well as that the vigorous growing period of plants was more serious than that in May and November, which are in the non-rainy season on the Chinese Loess Plateau. The vegetation types and soil depth were the key factors affecting the soil water deficiency status in the process of vegetation succession. Water-saving measures should be taken during the vigorous growing period of plants especially for those forest with natural restoration ages >50a on the Loess Plateau. The results could have great potential in the sustainable development of forestry and provide a theoretical basis for effective water management and reasonable vegetation restoration in semiarid loess regions.

Fertile island variation depends on species differences in the deserts of Northwest China

Desert ecosystems are extremely arid and nutrient poor. “Fertile islands” formed by mobile sand dunes and perennial desert plants are crucial for maintaining the structure and function of these ecosystems. However, the impacts of fertile islands created by different plant species at various spatial locations on soil physicochemical properties such as soil nutrients remain unclear. This study focused on the legumes (Astragalus flexus Fisch.), and non-legume (Eremurus inderiensis (M. Bieb.) Regel) plants widely distributed in the Gurbantunggut Desert in northwestern China. We analyzed the soil physicochemical properties of fertile islands formed by these two desert plants at different horizontal distances (0–140 cm) and vertical depths (0–15 cm). In addition, we investigated the relationship between plant functional shape and soil physicochemical properties. This study yielded the following results. (1) The fertile island was observed within the 0–140 cm soil layer of Astragalus flexus and Eremurus inderiensis and gradually weakened with increasing horizontal distance and soil depth. (2) The two plants had different nutrient enrichment rates. Eremurus inderiensis had higher TP and AK enrichment rates than Astragalus flexus. In contrast, Astragalus flexus demonstrated significantly higher enrichment rates for TN, NH4+-N, and NO3−-N, especially NH4+-N, highlighting the ability of legumes to fix and uptake N. (3) The correlation between plant height, crown width, and soil nutrient enrichment rate was more significant for Eremurus inderiensis than for Astragalus flexus. In general, both plants formed the fertile islands that gradually decreased with the increasing distance (both horizontal and vertical). Different plants exhibited varying abilities to enrich soil nutrients and form fertile islands, which presented a clear species effect. Therefore, protecting the diversity of desert plants to form stable fertile islands could be crucial for maintaining the soil fertility in desert ecosystems.

Nutrient Distribution Patterns in Soil Across Various Locations in Muzaffarnagar and Ghaziabad Districts of Uttar Pradesh under a Rice-Sugarcane Cropping Sequence

A study was conducted to evaluate the macro and micronutrient levels in the soil under the sugarcane-wheat cropping sequence and its relationship with soil characteristics. Understanding the nutrient status is vital for the efficient application of fertilizers, as widespread deficiencies in both macro and micronutrients are being reported in the soils of Uttar Pradesh. The rice-sugarcane cropping sequence is a prominent practice in the northwestern plains of Uttar Pradesh and Uttarakhand, covering 10-11% of the net cultivated area in these regions. Over recent years, sugarcane and wheat yields have plateaued in these areas due to declining factor productivity. Soil samples were collected from depths of 0-15 cm, 15-30 cm, and 30-45 cm at four locations in the Muzaffarnagar and Ghaziabad districts under the rice-sugarcane sequence. The available zinc content in the surface soil (0-15 cm) ranged from 0.605 to 0.883 mg/kg, and in the sub-surface soil (30-45 cm), it varied between 0.111 to 0.629 mg/kg, with an average of 0.083 mg/kg in surface soil and 0.435 mg/kg in sub-surface soil. A correlation analysis between various soil properties across different locations at three soil depths (0-15 cm, 15-30 cm, and 30-45 cm) was also conducted. The findings indicated that the soils are generally low in nitrogen, low to medium in phosphorus and potassium, and sufficiently supplied with copper, iron, manganese, and zinc in the surface layer. Future research on nutrient distribution in these areas will help advance precision agriculture, improve fertilizer management, and boost crop productivity while minimizing environmental harm. This research will contribute to sustainable soil management, economic benefits for farmers, and provide valuable insights for regional agricultural policies, further supporting food security.

Prediction of Soil Temperature in Wheat Field Using Machine Learning Models

ABSTRACT Wheat is a very vital cereal crop in the development of a nation’s economy and agricultural sector. A crucial element that profoundly affects the growth and productivity of wheat is the soil temperature. As an insulating layer, straw mulch controls the soil temperature. Field measurement of the soil temperature is time-consuming and costly; therefore, the present study investigates the applicability of random forest (RF), support vector machine (SVM) and generalized regression neural network (GRNN) models for estimating soil temperature in wheat fields covered with straw mulch using meteorological, soil cover and agronomical parameters. A field study was conducted on the wheat cultivar with two soil cover treatments for measuring the soil temperature at three depths (5, 50 and 80 cm). Soil plant analysis development value; soil cover and depth; daily meteorological data such as average air temperature, average relative humidity, sunshine hours and vapor pressure were used as inputs for machine learning models in training and testing. Statistical performance indicators showed applicability of three models with a root mean square error (RMSE) ranging from 0.245–0.595°C, 0.867–0.886°C and 0.557–0.812°C, Nash-Sutcliffe efficiency (NSE) ranging from 0.917–0.987, 0.823–0.836 and 0.804–0.935 and Lin’s concordance correlation coefficient (CCC) ranging from 0.949–0.991, 0.887–0.897 and 0.881–0.957 for the RF, SVM and GRNN, respectively. Results indicated better performance of the RF model for predicting the soil temperature at different depths in the case of both crop and soil cover conditions. Also, the uncertainty analysis indicated the better performance of RF with R-factor and P-factor value of 0.40 and 0.84, respectively.