Soil Electrical Conductivity Research Articles

Using Remote and Proximal Sensing Data and Vine Vigor Parameters for Non-Destructive and Rapid Prediction of Grape Quality

The traditional method for determining wine grape total soluble solid (TSS) is destructive laboratory analysis, which is time consuming and expensive. In this study, we explore the potential of using different predictor variables from various advanced techniques to predict the grape TSS in a non-destructive and rapid way. Calculating Pearson’s correlation coefficient between the vegetation indices (VIs) obtained from UAV multispectral imagery and grape TSS resulted in a strong correlation between OSAVI and grape TSS with a coefficient of 0.64. Additionally, seven machine learning models including ridge regression and lasso regression, k-Nearest neighbor (KNN), support vector regression (SVR), random forest regression (RFR), extreme gradient boosting (XGBoost), and artificial neural network (ANN) are used to build the prediction models. The predictor variables include the unmanned aerial vehicles (UAV) derived VIs, and other ancillary variables including normalized difference vegetation index (NDVI_proximal) and soil electrical conductivity (ECa) measured by proximal sensors, elevation, slope, trunk circumference, and day of the year for each sampling date. When using 23 VIs and other ancillary variables as input variables, the results show that ensemble learning models (RFR, and XGBoost) outperform other regression models when predicting grape TSS, with the average of root mean square error (RMSE) of 1.19 and 1.2 °Brix, and coefficient of determination (R2) of 0.52 and 0.52, respectively, during the 20 times testing process. In addition, this study examines the prediction performance of using optimized soil adjusted vegetation index (OSAVI) or normalized green-blue difference index (NGBDI) as the main input for different machine learning models with other ancillary variables. When using OSAVI-based models, the best prediction model is RFR with an average R2 of 0.51 and RMSE of 1.19 °Brix, respectively. For NGBDI-based model, the RFR model showed the best average result of predicting TSS were a R2 of 0.54 and a RMSE of 1.16 °Brix, respectively. The approach proposed in this study provides an opportunity to grape growers to estimate the whole vineyard grape TSS in a non-destructive way.

Medium-term interactive effects of herbivores and plant life form on the biochemistry of shallow sandy soils in a protected semi-arid savanna

Savannas are characterized by the co-occurrence of two different plant life forms: grasses and trees. Herbivory plays a major role in the balance between grasses and trees in savanna ecosystems. The present study aimed to investigate the impact and interactions between long-term (i.e. 20 years) herbivory and/or its exclusion and plant life form on the soil biochemistry of a protected semi-arid savanna ecosystem in the Kruger National Park (KNP), South Africa. To study the effects of herbivory on soil properties, herbivore exclosures (fully fenced areas, partially fenced areas, and an unfenced area) were used in conjunction with plant life form (trees and grasses) were considered. Interaction effects of herbivory and plant life form on soil pH, electrical conductivity (EC), total nitrogen (TN), total carbon (TC), available phosphorus (available P), exchangeable cations (K+, Na+, Mg2+ and Ca2+) cation exchange capacity (CEC), organic matter (OM) and total microbial activity were determined on savanna soils in the Nkuhlu exclosures, KNP. Exclosures where herbivores were present had significantly higher soil pH, The presence of herbivores caused an increase in soil pH, EC, exchangeable Na, CEC, and OM. The influence of the tree canopy was significantly more pronounced in elevating total C and N, exchangeable K+, Mg2+ and Ca2+, CEC and OM than observed in the open grassland zones across all exclosures. The two-way interaction between herbivory and plant life form resulted in significant decreases in TN, TC, exchangeable K, Na and Mg in open grassland areas outside of herbivore exclosures where large animals had direct access, as compared to areas within the exclosures which was protected from animal entry herbivory. This data can be used by national parks as an indicator to increase their knowledge of environmental issues relating to maintaining and preserving landscape features of savannas.

Black pepper pathogen suppression: Divergent rhizosphere fungal communities of healthy and diseased plants yield new insights for orchard management in Vietnam

Complex interactions involving soil physicochemical parameters and plant-associated microbial communities determine crop health. In Vietnam, this process is poorly understood in the context of black pepper production. Specifically, there is a dearth of information for improving the suppression of pathogenic fungi. Understanding the environmental dynamics influencing the distribution of these pathogens would facilitate the development and use of biological agents in black pepper pathogen management. Here, the molecular profiles of fungal communities from the rhizosphere of healthy and unhealthy Vietnamese black pepper orchards and their relationships were determined. Additionally, co-occurrence analyses with a previously constructed bacterial dataset identified taxa indicative of soil suppression. Alpha diversity of total fungi was influenced by only environmental factors, while that of arbuscular mycorrhizal fungi was more responsive to orchard health state. Glomus sp., Rhizophagus sp., Purpureocillium sp. and Plectosphaerella sp. were the most responsive genera to orchard health state. Potential fungal pathogens were more prevalent in the unhealthy orchards. Co-occurrence network analyses revealed that unhealthy orchards were less connected, had longer path distance and were missing putative pathogen-to-biocontrol interactions common in the healthy orchards. Soil electrical conductivity and potassium may be key factors in differentiating fungal communities of unhealthy from healthy orchards. This work highlights important microbial species and environmental considerations critical to improved black pepper management strategies.

Responses of Soil Microbial Survival Strategies and Functional Changes to Wet-Dry Cycle Events.

Soil microbial taxa have different functional ecological characteristics that influence the direction and intensity of plant-soil feedback responses to changes in the soil environment. However, the responses of soil microbial survival strategies to wet and dry events are poorly understood. In this study, soil physicochemical properties, enzyme activity, and high-throughput sequencing results were comprehensively anal0079zed in the irrigated cropland ecological zone of the northern plains of the Yellow River floodplain of China, where Oryza sativa was grown for a long period of time, converted to Zea mays after a year, and then Glycine max was planted. The results showed that different plant cultivations in a paddy-dryland rotation system affected soil physicochemical properties and enzyme activity, and G. max field cultivation resulted in higher total carbon, total nitrogen, soil total organic carbon, and available nitrogen content while significantly increasing α-glucosidase, β-glucosidase, and alkaline phosphatase activities in the soil. In addition, crop rotation altered the r/K-strategist bacteria, and the soil environment was the main factor affecting the community structure of r/K-strategist bacteria. The co-occurrence network revealed the inter-relationship between r/K-strategist bacteria and fungi, and with the succession of land rotation, the G. max sample plot exhibited more stable network relationships. Random forest analysis further indicated the importance of soil electrical conductivity, total carbon, total nitrogen, soil total organic carbon, available nitrogen, and α-glucosidase in the composition of soil microbial communities under wet-dry events and revealed significant correlations with r/K-strategist bacteria. Based on the functional predictions of microorganisms, wet-dry conversion altered the functions of bacteria and fungi and led to a more significant correlation between soil nutrient cycling taxa and environmental changes. This study contributes to a deeper understanding of microbial functional groups while helping to further our understanding of the potential functions of soil microbial functional groups in soil ecosystems.

Investigation of interaction effects of biochars and silicon on growth and chemical composition of Zea mays L. in a Ni-polluted calcareous soil

Biochars are cost effective, carbonaceous amendments that can immobilize potentially toxic elements (PTEs) in soils. Application of silicon (Si) has been shown to mitigate the effect of soil PTEs on plants. Studies on the interaction effects of Si and biochars in PTE-contaminated soils are limited. Thus, the aim of this study was to investigate the interaction effects of biochars, from sheep manure (SMB) and rice husk (RHB) produced at 300 and 500 °C, and 2 levels of Si (as sodium (Na) metasilicate), on growth and chemical composition of corn (Zea mays) in a nickel (Ni)-polluted calcareous soil. The combined application of Si and biochars significantly reduced soil available Ni (17–32%) and the corn shoot Ni concentrations (29–58%), associated with soil pH increase (r = 0.56–0.60, P < 0.01). Application of SMB resulted in greater soil pH increases compared to RHB, and increased soil electrical conductivity (EC) to saline levels, attributed to its higher ash content. Increasing Si application levels also increased soil pH and EC values. Application of all the biochars resulted in significant biomass increases, with RHB having the most positive effect. Despite the positive effect on soil Ni immobilization, the combined application of Si and biochars generally resulted in a decrease in corn shoot biomass yields compared to biochars alone. The biomass decrease was attributed to the significantly higher soil sodicity and pH in the combined treatments which resulted in suppression of macro and micronutrient uptake by the corn. Although the combination of biochar and Na metasilicate was effective at immobilizing soil Ni, future studies should rather employ other essential basic cation metasilicates.

Unveiling the impacts moso bamboo invasion on litter and soil properties: A meta-analysis

Moso bamboo invasion potentially alters litter, soil properties and soil microbial communities in forest ecosystems. However, the overall direction and magnitude of this alteration at a large spatial scale remain unclear. Here, we conducted a meta-analysis of 72 experimental studies on the impact of moso bamboo invasion on litter, soil physicochemical properties, and soil microbial communities. Overall, the moso bamboo invasion increased litter decomposition, soil pH, and NH4+-N, while concurrently leading to a decrease in soil bulk density, soil electrical conductivity, soil TN: TP ratio, soil NO3−-N, and available potassium. Moreover, we observed that the invasion significantly enhanced soil microbial biomass nitrogen, fungal ACE diversity index, fungal biomass, and bacterial Shannon diversity index, while decreasing the ratio of Gram-positive to Gram-negative bacteria and the biomass of Gram-positive bacteria. Furthermore, we identified the primary factors influencing specific soil properties and microbial community responses to moso bamboo invasion. Specifically, the response of NH4+-N, NO3−-N, soil bulk density, fungal diversity and pH were found to be primarily influenced by climatic factors (mean annual temperature, mean annual precipitation), topographic factors (aspect), and invasion stage, respectively. In addition, we further revealed a close relationship between soil physicochemical properties and microbial communities during moso bamboo invasion. Specifically, the response of soil microbial biomass nitrogen was positively correlated with the responses of soil organic nitrogen and total nitrogen content, Gram-positive bacteria biomass was positively correlated with soil total nitrogen but negatively correlated with soil pH. Meanwhile, soil bacterial diversity showed a significant positive correlation with soil pH but exhibited a negative correlation with soil SOC. Our study suggests that macro-climatic conditions, local microenvironment, and invasion stage co-regulate the important effects of moso bamboo invasion on litter, soil physicochemical properties, and microbial communities.

The reconstruction impact on the urban ecosystem park plantings on the example of the Oles Gonchar Dnipro National University Botanical Garden

The article is devoted to the study of the reconstruction impact on park plantings located in the Oles Honchar Dnipro National University Botanical Garden. The reconstruction of the botanical garden was carried out in 2018 and consisted of the removal of 74 old trees, sanitary pruning of some plantings, and the laying of asphalt paths. To determine the impact of the reconstruction on the greenery of the DNU Botanical Garden, four test plots were laid down: plots a and b in the reconstruction area, plots c and d in the unreconstructed area. The following physical parameters of the soil were measured at the test sites: soil penetration resistance, electrical conductivity and moisture. The research was conducted in April – May 2021. Soil penetration resistance is an informative indicator sensitive to anthropogenic impact, its measurement is fast and allows obtaining significant amounts of information in a short time. Electrical conductivity is related to soil moisture and salt content. These indicators, combined with phytoindication methods, allowed us to draw conclusions about the impact of the reconstruction on the soil and green spaces. The landfills differed significantly after reconstruction in terms of the profile distribution of average soil penetration resistance values. The reconstruction area soil is characterized by the appearance of peak soil penetration resistance values at depths of 35–50 cm and 85–90 cm. Polygons a and b have much higher values of topsoil penetration resistance than polygons c and d. The coefficient of variation of soil penetration resistance profile distribution at the test sites in the reconstruction zone also demonstrates a specific character – it has a pronounced peak at a depth of 25–40 cm and gradually decreases with depth. The conclusion about the reconstruction impact on the soil penetration resistance of the botanical garden soil changes was made based on the results of the General Linear Model, which was estimated by the Radj2 index. The distribution of soil electrical conductivity values has a pronounced bell-shaped character. At all the test sites, there is a tendency for electrical conductivity increasing which is positively correlated with moisture. By means of the phytoindicative scales the hemerobia index was determined, which demonstrated a statistically significant linear relationship (p &lt; 0.001) with soil electrical conductivity.

Sand-Related Factors Influencing Nest Burrowing Potential of the Sand Martins.

Vertical embankments and mounds serve as suitable habitats for burrowing birds, such as the Sand Martin (Riparia riparia). Sand Martins have decreased in many countries during the last two decades, possibly because of the decline in suitable nest sites. Therefore, it is important to understand the factors affecting nest burrowing and nest hole characteristics for the Sand Martin. A smaller entrance hole would be beneficial for regulating the internal environment of the nest, whereas deeper nests are more advantageous against nest predators and parasites. We examined the general structure of Sand Martin colonies and determined if particle size, pH, or electrical conductivity (EC) of the soil and the location of the colony affects the morphology of Sand Martin nest holes. We hypothesized that the climate of near lakeshore and non-lakeshore differs; consequently, we predicted that Sand Martins would construct wider nest tunnel entrances in more humid environments near the lakeshore than further from the lake. We also hypothesized that a lower pH of clay loam soil would result in an increasing level of exchangeable aluminum (Al) and acidity, which in turn would promote soil aggregation. Because soils with a low EC are more stable and less prone to flooding or erosion, we predicted that Sand Martins in such soils would have deeper nesting burrows. A total of four colonies were located in the study area in Turkey. They contained 2510 burrows, of which 91.83% were used for breeding. The mean colony size was 627. We measured the soil and the nest burrow characteristics from the 80 nest bottoms used for breeding by the Sand Martin. The mean pH was 8.8, and the mean EC was 171. Tunnel depth was longer in nests with greater pH and EC and in lakeshore than in non-lakeshore colonies. The distance between nest holes increased with the EC, and nests were located nearer to each other in the lakeshore colonies than in non-lakeshore colonies. The width of the entrance opening increased with soil particle size and was wider in nests located at the lakeshore areas. Our results indicated that Sand Martins will avoid sites with too compact or loose soils for nesting, probably to avoid nest collapses. Vertical lakeshore embankments offer good nesting sites for Sand Martins and should, therefore, be protected. Because soil particle size, pH, EC, and distance from the lakeshore influenced the nest hole characteristics of the Sand Martin, conservation and management efforts should take these variables into account when maintaining or establishing suitable soil conditions for the Sand Martin.

Responses of lettuce (Lactuca sativa L.) growth and soil properties to conventional non-biodegradable and new biodegradable microplastics

Residual plastic films in soils are posing a potential threat to agricultural ecosystem. However, little is known about the impacts of microplastics (MPs) derived from biodegradable and non-biodegradable plastic films on plant-soil systems. Here, we carried out a pot experiment using soil-cultivated lettuce treated by two types of MPs, degradable poly(butylene adipate-co-terephthalate) (PBAT-MPs) and non-biodegradable polyethylene (PE-MPs). MPs resulted in different degrees of reduction in shoot biomass, chlorophyll content, photosynthetic parameters, and leaf contents of nitrogen (N), phosphorus (P), and potassium (K), accelerated accumulation of hydrogen peroxide and superoxide, and increased malondialdehyde content in lettuce leaves. Moreover, MPs obviously decreased contents of total N, nitrate, ammonium, and available K in soils, and increased available P, thus altering soil nutrient availability. MPs also significantly decreased proportions of macroaggregates, and decreased soil electrical conductivity and microbial activity. PBAT-MPs had significantly greater impacts on oxidative damage, photosynthetic rate, soil aggregation, microbial activity, and soil ammonium than those of PE-MPs. Our results suggested that MPs caused oxidative damages, nutrient uptake inhibition, soil properties alteration, ultimately leading to growth reduction, and PBAT-MPs exhibited stronger impacts. Therefore, it is urgent to further study the ecological effects of MPs, especially biodegradable MPs, on soil-plant systems.

Visible and near infrared spectroscopy for predicting soil nitrogen mineralization rate: Effect of incubation period and ancillary soil properties

Soil nitrogen mineralization rate (SNMR) influences crop N uptake and nitrate leaching leading to environmental pollution. This study aims at (i) examining whether visible and near-infrared reflectance spectroscopy (vis-NIRS) can predict SNMR and (ii) investigating if incubation periods and ancillary soil attributes can improve the prediction accuracy. Total 133 soil samples collected from seven fields were incubated under aerobic conditions for 60 days with seven batches of sub-samples. Mineral N was measured at regular time intervals and soil samples were scanned using a vis-NIRS sensor (Tec5 Technology, Germany) parallelly. SNMR was determined by fitting a zero-order kinetic to the net mineralized N as a function of the incubation time. Soil total nitrogen (TN), total carbon (TC) and electrical conductivity (EC) were determined once. Partial least squares regression (PLSR) models were calibrated individually for each field both for vis-NIR spectra and its combinations with TN, TC and EC. Six out of seven batches of sub-samples were used for calibrating PLSR when remaining one batch was used for model validation, and it rotated across all seven batches. Vis-NIRS alone predicted SNMR with moderate accuracy in five of seven fields (coefficient of determination, 0.53 ≤ R2 ≥ 0.66, ratio of prediction to deviation, 1.51 ≤ RPD ≥ 1.76), while models were poor in two fields (R2 = 0.23–0.26, RPD = 1.18 – 1.20). Inclusion of soil TC, TN and/or EC was expected to improve accuracy, but improvements varied across fields (R2 = 0.23–0.79, RPD = 1.18 – 2.26). Similarly, the incubation period increased vis-NIRS prediction accuracy, but frequently occurred among 2nd to 6th batches (R2 = 0.35–0.82, RPD = 1.28 – 2.44). Even incorporating secondary properties and increasing incubation duration hardly improved predictions, improvement can be compromised since it is not significant mostly and often underperformed or remained unchanged. Considering the time and effort required to incubate and analyze soil properties, this study suggests using a vis-NIRS sensor to estimate SNMR in fresh soil conditions i.e., without incubation and incorporation of secondary properties.

Responses of silver fir (Abies alba Mill.) seedlings from different geographical locations to low temperature stress

Climate change has exacerbated difficulties for both the environment and humans in recent years, with major consequences on the resilience and ecological diversity of forests, including those of silver fir (Abies alba Mill.). Because cold stress is an important challenge to silver fir seedling growth, particularly in the early phases of development, the goal of this study was to find potential genetic resources with appropriate responses to the action of low temperatures. Thus, traits of interest were studied in the early stage of seedlings from seven different Romanian provenances. Soil electrical conductivity, root weight, and total seedling weight were found to be related to seedling growth and biomass elements. The results revealed substantial differences depending on geographical origin. Garda Seaca provenance had the highest seedlings tolerance. Exposure to varying low temperatures revealed minor variations between seedlings from the control and those treated to −20 °C, which might be explained by the current temperatures in Romania’s silver fir producing area. However, exposing to −40 °C all seedlings showed deterioration. Soil electroconductivity reduced as exposure temperature decreased, emphasizing the link between cold stress and soil effects on fir seedling growth. Some Romanian provenances could be useful for future silver fir breeding or afforestation and reforestation operations.

Synergistic effect of biochar-based compounds from vegetable wastes and gibberellic acid on wheat growth under salinity stress

Soil salinization is a prevalent form of land degradation particularly in water-deficient regions threatening agricultural sustainability. Present desalinization methods demand excessive water use. Biochar has been recognized as a potential remedy for saline soils and Gibberellic acids (GA3) are known to mediate various biochemical processes aiding in stress mitigation. This study was undertaken at The Islamia University of Bahawalpur during winter 2022–23 to explore the combined effect of biochar and GA3 on wheat (Triticum aestivum L.) in saline conditions. Employing a fully randomized design wheat seeds in 24 pots were subjected to two salinity levels with three replications across eight treatments: T1 to T8 ranging from controls with different soil electrical conductivities (ECs) to treatments involving combinations of GA3, biochar and varying soil ECs. These treatments included T1 (control with soil EC of 2.43dS/m), T2 (salinity stress with soil EC of 5.11dS/m), T3 (10 ppm GA3 with soil EC of 2.43dS/m), T4 (10 ppm GA3 with soil EC of 5.11dS/m), T5 (0.75% Biochar with soil EC of 2.43dS/m), T6 (0.75% Biochar with soil EC of 5.11dS/m), T7 (10 ppm GA3 combined with 0.75% biochar at soil EC of 2.43dS/m) and T8 (10 ppm GA3 plus 0.75% biochar at soil EC of 5.11dS/m). The results indicated that the combined applications of GA3 and biochar significantly enhanced plant growth in saline conditions viz. germination rate by 73%, shoot length of 15.54 cm, root length of 4.96 cm, plant height of 16.89 cm, shoot fresh weight 43.18 g, shoot dry weight 11.57 g, root fresh weight 24.26 g, root dry weight 9.31 g, plant water content 60.77%, photosynthetic rate 18.58(CO2 m−2 s−1) carotenoid 3.03 g, chlorophyll a 1.01 g, chlorophyll b 0.69 g, total chlorophyll contents by 1.9 g as compared to the control. The findings suggest that the combined application of these agents offers a sustainable and effective strategy for cultivating wheat in saline soils. The synergy between biochar and GA3 presents a promising avenue for sustainable wheat cultivation in saline conditions. This combined approach not only improves plant growth but also offers an innovative, water-efficient solution for enhancing agricultural productivity in saline-affected regions.

Soil structure shifts with earthworms under different organic fertilization in salt‐affected soils

AbstractEarthworm incubation combined with organic fertilization is promoted as an amended measure to improve soil properties in the ecological restoration of various degraded soils. However, the impacts of earthworms on the soil aggregate size under different organic fertilization in salt‐affected soils have not yet been fully revealed. This hinders our ability to develop policies by which to alleviate soil salinization. In this study, under mesocosm experiments, we investigate the effects of earthworm (Aporrectodea trapezoides) and organic fertilization on the soil aggregate size after 16 weeks of incubation. The soil treated with clover residues showed lower earthworm survival rates and biomass compared to that treated with sheep manure. However, the soil macropores and large macroaggregate were higher in the soils treated with clover residue when earthworms were present. In addition, earthworm burrowing activities form pathways toward food patches improve the characteristics of soil macropores, and the properties of the residue itself play a decisive role. Moreover, whether earthworms are present or not significantly influences the soil macroporosity, macropore number, and soil electrical conductivity. This demonstrates that earthworms exhibit a key feature of soil physical functioning in salt‐affected soil. In conclusion, we propose that the application of earthworms with organic residues in salt‐affected soils is a priority in producing and maintaining favorable soil structure.

Prebiotics: A Solution for Improving Plant Growth, Soil Health, and Carbon Sequestration?

Soil fertility and productivity are severely impacted by exploitation and degradation processes. These threats, coupled with population growth and climatic changes, compel us to search for innovative agroecological solutions. Prebiotics, a type of soil biostimulant, are used to enhance soil conditions and plant growth and may play a role in carbon (C) sequestration. Two commercial prebiotics, K1® and NUTRIGEO L® (referred to as SPK and SPN, respectively), were assessed for their effects on agricultural soil cultivated with Zea mays L., compared to untreated soil or control (SP). Analyses were performed at two harvesting dates: three weeks (D1) and ten weeks (D2) after the application of prebiotics. Plant growth parameters and soil characteristics were measured, focusing on soil organic matter, soil bacterial and fungal communities, and plant root mycorrhization. Regarding physicochemical parameters, both prebiotic treatments increased soil electrical conductivity, cation exchange capacity, and soluble phosphorus (P) while decreasing nitrates. Meanwhile, the SPN treatment was distinct in elevating specific cationic minerals, such as calcium (Ca) and boron (B), at D2. At the microbial level, each prebiotic induced a unique shift in the indigenous bacterial and fungal communities’ abundance and diversity, evident at D2. Simultaneously, specific microbial taxa were recruited by each prebiotic treatment, such as Caulobacter, Sphingobium, and Massilia from bacteria and Mortierella globalpina and Schizothecium carpinicola from fungi in SPK as well as Chitinophaga, Neobacillus, and Rhizomicrobium from bacteria and Sordariomycetes and Mortierella minutissima from fungi in SPN. These biomarkers were identified as (a) saprotrophs, (b) plant growth-promoting bacteria and fungi, (c) endohyphal bacteria, and (d) endophytic and symbiotic microbiota. This result was reflected in the increase in glomalin content and mycorrhization rate in the treated soils, especially by SPN. We observed that these effects led to an increase in plant biomass (shoots by 19% and 22.8% and roots by 47.8% and 35.7% dry weights for SPK and SPN, respectively) and contributed to an increase in soil C content (organic C by 8.4% and total C by 8.9%), particularly with SPN treatment. In light of these findings, the use of prebiotics ten weeks after application not only increased plant growth by improving soil characteristics and shaping its native microbial community but also demonstrated the potential to enhance C sequestration.

Spatial Variability of Soil Macronutrients and Chemical Properties in Ujjain Tehsil of Ujjain District of Madhya Pradesh, India

Understanding the characteristics of soil and how it may be utilised sustainably makes soil property mapping a crucial process. To improve crop yield and preserve healthy soil, it is essential to understand the heterogeneity of the soil in each location in order to establish site-specific nutrient management strategies for that area. The current research was carried out in the Ujjain tehsil (Ujjain) district of Madhya Pradesh state, India, with the aim of measuring the spatial variability of several soil macronutrients and soil chemical characteristics. Throughout the research region, 150 geo-coded surface soil samples with a depth of 0 to 15 cm were collected. The soil characteristics, namely pH, electrical conductivity (EC), soil organic carbon (SOC), available nitrogen (Av-N), available phosphorous (Av-P), available potassium (Av-K), and available sulphur (Av-S), were assessed in these samples using standard methods. The research region's ranges for soil pH, EC, SOC, Av-N, Av-P, and Av-K were 7.01 to 8.15, 0.10 to 0.79 dSm-1, 0.30-0.60%, 139.00 – 235.00 kg ha-1, 8.00 – 25.60 kg ha-1, and 301.00 – 463.00 kg ha-1, in that order. The data were analysed using classic statistics and geo--statistics by constructing semi-variograms and mapping by ordinary kriging techniques. Semi-variograms were calculated for soil characteristics and their spatial distributions were mapped. Best-fit models for measured soil properties were Exponential, Circular, Gaussian and Hole effect with Nugget/Sill (Co/Co+C) ratio for modelled variables indicated strong and moderate spatial dependences. The distribution maps of soil attributes could be utilized as a guide for site-specific crop management in similar soils. Further, this study demonstrates the usefulness of GIS- application in soil variability studies.

Effects of Different Zinc and Copper Concentrations in Soil on Morphological and Biochemical Properties of Ipomea aquatica

Zinc and copper pollution in agricultural lands due to anthropogenic activities has become a major environmental problem. While these metals are essential for plant growth, their excessive presence can lead to plant toxicity. This experiment aimed to investigate the effects of different concentrations of zinc and copper (0, 100, 200, and 300 ppm) in soil on the morphological and biochemical properties of I. aquatica, commonly known as water spinach. The morphological properties, including plant height, number of leaves, and stem diameter, were assessed, along with soil pH and electrical conductivity (EC). Biochemical properties, specifically the Total Phenolic Content (TPC) and Total Flavonoid Content (TFC) in plant tissues, were measured using colorimetric assays. The results revealed significant morphological changes in plant height, stem diameter, and number of leaves at 200 ppm zinc treatment compared to the control. Additionally, the number of leaves significantly increased at the 100 ppm copper treatment, while the stem diameter decreased significantly at 300 ppm. Both zinc and copper treatments slightly reduced soil pH and increased soil EC. At the 300 ppm treatment, substantial changes in phenolic and flavonoid contents were observed in the stems and leaves of I. aquatica. Copper treatment at 200 ppm increased the TPC of leaves, while 100 ppm copper treatment increased the TFC of stems. Furthermore, the 300 ppm zinc treatment significantly increased the TPC and TFC in stems and leaves. These findings indicate that zinc and copper concentrations have notable effects on the morphological and biochemical properties of I. aquatica. Therefore, it is crucial to maintain an appropriate balance of these metal elements to cultivate plants that are morphologically and physiologically resilient.

Quantitative relationship between soil pH and electrical conductivity values and cadmium phytoavailability for Chinese cabbage under simulated conditions

Pot experiments were conducted to investigate the impacts of continuous addition of different concentrations of calcium chloride (CaCl2) and/or low-molecular-weight organic acids (LMWOAs) on soil pH, electrical conductivity (EC), and cadmium (Cd) transformation. These factors subsequently affected Cd phytoavailability in a system consisting of Cd-contaminated soil and Chinese cabbage (Brassica chinensis L.). The results indicate that CaCl2 addition had a greater impact on reducing soil pH value, increasing soil EC value, and enhancing Cd phytoaccumulation in Chinese cabbage compared to LMWOAs. When soil pH dropped by 0.3 unit and the soil EC increased by 500 µS cm−1, the Cd concentration in the Chinese cabbage shoots was 3 times higher than that in the control group. Throughout two planting terms of Chinese cabbage, the addition of CaCl2 (1.6–3.2 g kg−1) and LMWOAs (≤ 1.0 g kg−1) led to phytoextracted Cd concentration exceeding exchangeable Cd concentration in soil samples before the pot experiment. Regarding phytoextracted Cd, desorption from carbonate-bound Cd contributes more than desorption from bound to organic matter Cd and adsorption to Fe/Mn oxide Cd. This study underscores the influence of soil pH and EC value variations and Cd transformation on Cd phytoavailability. Special attention should be given to leafy vegetables grown in Cd-contaminated soil, as the phytoavailable Cd concentration reaches approximately 2.0 µg kg−1, which may lead to Cd levels surpassing acceptable limits for Chinese cabbage.

Soil Microbial Communities Show Different Patterns under Different Land Use Types in the Coastal Area of Nantong, China

Tidal flats in eastern China have undergone various transformations into other land-use types. Understanding the impact of land-use conversion on soil properties and microbial communities is crucial for effective ecological conservation efforts. In this study, we compared soil chemical properties and the diversity, composition, and ecological functions of soil bacterial and fungal communities across four land-use types: natural bare land (BL), unused reclaimed tidal land (Phragmites, PL), agricultural land (maize, ML), and shelterbelt land (SL), utilizing next-generation sequencing technology. The results indicated that soil electrical conductivity decreased, while soil organic carbon (SOC) and nutrient contents increased in ML and SL compared to BL and PL. The bacterial Chao1 and fungal Chao1 and Shannon values vary across different land-use types. A higher relative abundance of Acidobacteriota, specifically RB41, was found in ML compared to BL. Principal coordinate and PerMANOVA analysis showed that the composition of bacterial and fungal communities differed significantly across the four land-use types. SOC explained the most variance in both bacterial and fungal communities. Carbon-related functional genes and fungal guilds exhibit greater diversity across the four land-use types compared to nitrogen-related functional genes. In conclusion, the transformation of natural land-use types to managed one greatly altered soil chemical and microbial properties. Our study offers foundational insights into the microbial communities in the typical land-use types of Eastern China’s coastal area. Future studies should emphasize the quantification of human interventions and their impact on soil microbial communities and ecological functions.

Optimal timing of satellite data acquisition for estimating and modeling soil salinity in cotton fields of the Mingbulak District, Uzbekistan

Agriculture is frequently hampered by soil salinity, which has a negative impact on crop growth and yield. This study aims to identify the optimal timing of satellite data acquisition to predict soil salinity levels indirectly using satellite images in cotton growth fields as a basis. Data was collected in the Mingbulak district of Uzbekistan, where soil electrical conductivity (EC) was measured in a laboratory using soil samples collected from various fields with similar management practices. In this research, we present a linear regression model that uses satellite data and the Normalized Difference Salinity Index (NDSI) to forecast soil salinity levels indirectly. The results of the linear regression analysis showed a positive correlation between the soil electrical conductivity values and the NDSI values for each month, with August having the highest correlation (R2 = 0.70). The study found that the cotton growth stages and the process of soil salinity formation in the study area were the main factors affecting the correlation between electrical conductivity and NDSI. The model developed in this study has R2 value of 0.70. This suggests a moderate to strong relationship between the two variables, which is promising for the indirect assessment of soil salinity using the NDSI index. The study discovered a positive relationship between soil electrical conductivity and NDSI values, which were highest in pre-flowering and flowering stages of cotton. Our findings show that satellite-based estimation and modeling with NDSI can be used to indirectly assess cotton field soil salinity, especially during the pre-flowering and flowering stages. This study contributes to the development of optimal satellite data acquisition timing, which can improve soil salinity predictions and agricultural productivity.

Response of Graded Fertility Levels and Zinc Application Method with and without Farm Yard Manure on Physicochemical and Biological Properties of Soil under Rice Crop

The field experiment was conducted during Kharif season 2022 at Student’s Instructional farm of Acharya Narendra Deva University of Agriculture and Technology Kumarganj, Ayodhya Uttar Pradesh, India. The experiment was laid out in Randomized Block Design (RBD) with three replications and ten treatments. The experiment comprised of ten treatments viz., T1: Control, T2: 100% RDF (150, 60, 40 N, P2O5, K2O kg ha-1), T3: 100% RDF + 25 kg ZnSO4 ha-1 soil application, T4: 100% RDF + 0.5% ZnSO4 spray at tillering stage, T5: 100% RDF + 0.5% ZnSO4 spray at tillering stage + PI stage, T6: 75% RDF + 25 kg ZnSO4 ha-1 soil application, T7: 75% RDF + 0.5% ZnSO4 spray at tillering stage, T8: 75% RDF + 0.5% ZnSO4 spray at tillering stage + PI stage, T9: 75% RDF + 25% FYM-N +0.5% ZnSO4 spray at tillering stage + PI stage and T10: 75% RDF + 25% FYM-N +25 kg ZnSO4 ha-1 soil application. The application of 75% RDF + 25% FYM-N +25 kg ZnSO4 ha-1 soil application has non-significantly effect on Bulk density, pH, Electrical Conductivity of soil after harvest of rice crop. The application of 75% RDF + 25% FYM-N +25 kg ZnSO4 ha-1 soil application has significantly influenced Organic carbon, Available N, P, K and Zn in soil.