Content Index Research Articles

Canopy transpiration and its controlling mechanisms among rainfall patterns in a boreal larch forest in China

Rainfall patterns affect vegetation water use through canopy transpiration (Ec) and are becoming increasingly variable due to global warming. However, Ec and its controlling mechanisms in boreal forests have rarely been investigated under various rainfall patterns. In this study, we measured the sap flow using thermal dissipation method in a boreal larch forest (Larix gmelinii) and observed biophysical variables simultaneously (e.g., air temperature, solar radiation, relative humidity, vapor pressure deficit, wind speed, soil water content, rainfall, and leaf area index) over two consecutive growing seasons (May–September) in 2021 and 2022. The responses of Ec to rainfall patterns were evaluated among three rainfall categories (classified based on rainfall amount, duration, and intensity), five types of rainfall timing, and two phenology periods (i.e., leaf expansion and defoliation periods). The results showed that daytime Ec significantly decreased, while nighttime Ec was less variable with increasing rainfall amount, duration, and intensity. The responses of Ec to rainfall categories with different rainfall amount, duration, and intensity were inconsistent at the monthly scale. The magnitude and diurnal dynamics of Ec were greatly influenced by the rainfall timing, and these effects got more considerable with increasing rainfall amount, duration, and intensity. Surprisingly, Ec showed opposite responses to rainfall in leaf expansion and defoliation periods, suggesting an enhanced impact in the leaf expansion period while a diminished impact in the leaf defoliation period. The significantly affected biophysical factors of Ec varied dramatically among rainfall categories. The interactions between biophysical factors and Ec were more complex and diverse in days without rainfall events than days with rainfall days. These findings highlight the importance of rainfall patterns in affecting Ec, provide new insight into the interactions between rainfall patterns, Ec, and biophysical factors, and are important supports for improving evapotranspiration simulations in the context of climate change.

Structure and stability characteristics of zonal soil aggregates in the Three Rivers Source of the Qinghai‐Tibetan Plateau

AbstractThis study aimed to explore the structure and stability characteristics of zonal soil aggregates in cold high‐altitude regions and reveal the variation patterns of alpine soil aggregates, using the Three Rivers Source of the Qinghai‐Tibetan Plateau as an example. Zonal soils representing the local vegetation types (alpine meadow soil, alpine grassland soil) were collected, and soil aggregates were separated using wet and dry sieving methods. Random forest modeling was used with climate data from 2011 to 2019 as variables in order to generate multifactor digital maps of water‐stable and mechanically stable aggregates. The composition and differences of zone‐specific soil aggregates were compared and analyzed using the evaluation indices of macroaggregate content (R > 0.25), mean weight diameter (MWD), geometric mean diameter, and fractal dimensions. Their controlling factors were also explored. The study results showed that the model's explanatory power for soil aggregates was over 68%. In the random forest model, elevation and sunshine duration contributed more to soil water‐stable aggregates, whereas precipitation contributed more to soil mechanically stable aggregates. The content of large aggregates with particle size greater than 0.5 mm was higher in alpine meadow soils than in alpine grassland soils. In contrast, the content of large aggregates with particle size less than 0.5 mm was lower than that of alpine grassland soils. There are also some differences in the distribution of water‐stable aggregates and mechanically stable aggregates between alpine meadow soils and alpine grassland soils in each particle size, and these differences are most pronounced in the particle sizes >2 and <0.25 mm. In addition, the stability of alpine meadow soil aggregates is higher than that of alpine grassland soil aggregates. Finally, the mapping results show that the stability of soil aggregates in the study area has similar zonal characteristics to the zonal variation of vegetation cover and climate and other factors.

Transforming Bombax ceiba L. sawdust waste into a valuable growth substrate: An example with sugarcane

The rising prices of peat moss and coco-peat caused by the gradual depletion of natural resources have derived researchers to explore new soilless alternatives which are inexpensive, productive, and sustainable. Conversion of sawdust waste into productive compost can be an applicable solution. The research objective was to test the composted mixtures of Bombax ceiba L. sawdust as soilless substrates to raise sugarcane seedlings. Over two years of experiments, a range of B. ceiba sawdust treatments were used. The germination, seedlings height, leave numbers plant−1, chlorophyll content index, leaf area, the diameter of the stem, and shoot and root (fresh and dry) weights were higher in seedlings grown in all B. ceiba sawdust compost mixtures than in soil. In conclusion, B. ceiba 60 %, mixed with banana peels 20 %, eggshells 20 % (v/v), and urea at a rate of 158 kg N ha−1 can be a productive and inexpensive soilless alternative to raise sugarcane seedlings.

Improved description of terrestrial habitat types by including microbial communities as indicators

Soils host diverse communities of microorganisms essential for ecosystem functions and soil health. Despite their importance, microorganisms are not covered by legislation protecting biodiversity or habitats, such as the Habitats Directive. Advances in molecular methods have caused breakthroughs in microbial community analysis, and recent studies have shown that parts of the communities are habitat-specific. If distinct microbial communities are present in the habitat types defined in the Habitats Directive, the Directive may be improved by including these communities. Thus, monitoring and reporting of biodiversity and conservation status of habitat types could be based not only on plant communities but also on microbial communities. In the present study, bacterial and plant communities were examined in six habitat types defined in the Habitats Directive by conducting botanical surveys and collecting soil samples for amplicon sequencing across 19 sites in Denmark. Furthermore, selected physico-chemical properties expected to differ between habitat types and explain variations in community composition of bacteria and vegetation were analysed (pH, electrical conductivity (EC), soil texture, soil water repellency, soil organic carbon content (OC), inorganic nitrogen, and in-situ water content (SWC)). Despite some variations within the same habitat type and overlaps between habitat types, habitat-specific communities were observed for both bacterial and plant communities, but no correlation was observed between the alpha diversity of vegetation and bacteria. PERMANOVA analysis was used to evaluate the variables best able to explain variation in the community composition of vegetation and bacteria. Habitat type alone could explain 46% and 47% of the variation in bacterial and plant communities, respectively. Excluding habitat type as a variable, the best model (pH, SWC, OC, fine silt, and Shannon's diversity index for vegetation) could explain 37% of the variation for bacteria. For vegetation, the best model (pH, EC, ammonium content and Shannon's diversity index for bacteria) could explain 25% of the variation. Based on these results, bacterial communities could be included in the Habitats Directive to improve the monitoring, as microorganisms are more sensitive to changes in the environment compared to vegetation, which the current monitoring is based on.

Impact of organic fertilization by the digestate from by-product on growth, yield and fruit quality of tomato (Solanum lycopersicon) and soil properties under greenhouse and field conditions

BackgroundThe application of organic fertilizer is a sustainable approach to maintain soil fertility in agricultural crop production. In contrast to other organic fertilizers, the digestate from by-products of anaerobic digestion has not been well characterized in terms of its agronomic properties. In this study, different fertilization treatments were investigated to evaluate their impacts on growth, yield and fruit quality of tomatoes and on soil properties under greenhouse and field conditions. The experiments comprised a control (unfertilized) and three treatments with the same nitrogen dose: chemical fertilizer, digestate from by-product (organic fertilizer) and digestate combined with chemical fertilizer.ResultsThe results showed that the application of digestate significantly increased the growth and fruit quality of tomato including height, stem diameter, leaf chlorophyll content index, and photosynthetic rate of tomato plant and sugar–acid ratio, protein content, and ascorbic acid content of the fruit. The nitrate contents in tomato fruit were lower in the digestate treatment and digestate combined with chemical fertilizer treatment than in the chemical fertilizer. The digestate combined with chemical fertilization resulted in the greatest increase in tomato yield, up to 26.29% and 10.78% higher than that in the chemical fertilizer treatment under field and greenhouse conditions, respectively. Moreover, fertilization with digestate treatment and digestate combined with chemical fertilizer treatment increased soil fertility, including soil nitrogen and carbon contents, and enhanced soil enzyme activities under both field and greenhouse conditions. In addition, the growth, yield, and fruit quality of tomato were significantly correlated with soil chemical characteristics and soil enzyme activities.ConclusionsThe effects of digestate treatments to maintain a stable tomato yield and improve fruit quality may be due to the enhanced soil enzymatic activities and chemical properties. These results suggest that the use of digestate as a full or partial replacement for chemical fertilizer could improve the growth and fruit quality of tomato, maintain the yield, and reduce the use of inorganic fertilizers in tomato production.Graphical

Integrated effects of meteorological factors, edaphic moisture, evapotranspiration, and leaf area index on the net primary productivity of Winter wheat − Summer maize rotation system

Net primary productivity (NPP) assumes a pivotal role in the realm of plant growth, organic matter production, and carbon cycling. Nevertheless, the mechanism underlying the integrated effects of meteorological factors, soil water content (SWC), evapotranspiration (ET), and leaf area index (LAI) on the NPP in agricultural systems remains unclear. Elucidating the evolution pattern of NPP in agricultural system and its responding mechanism to meteorological factors, SWC, ET, and LAI hold pronounced significant for sustainable agricultural operation, agroecological maintenance, and climate-adaptive strategy optimization. This study focused on the winter wheat - summer maize rotation, a predominant agricultural system, in the North China Plain (NCP). Spatiotemporal pattern of NPP was clarified using geostatistical technique, Mann-Kendall test, Sen's Slope, and Rescaled Range analysis. The mechanism underlying the integrated response of NPP to different meteorological factors, SWC, ET, and LAI was revealed through spatiotemporal coupling correlation analysis, Random Forest, and Structural Equation Modeling. The results demonstrated a widespread annual increase in NPP across the majority of rotation areas from 2000 to 2019, with a prominent geospatial heterogeneity. Meteorological factors, SWC, ET, and LAI collectively explained 70.27% of NPP variability. Of which, ET, FAPAR, P, LAI, Tmax, Tmin, and the SWC in 40–100 cm were predominant factors affecting NPP, explaining 63.59% of its variability. These factors exerted multidimensional effects on NPP, instead of a unilateral induction. Despite the limited direct effect, precipitation indirectly improved NPP by significantly increasing the SWC in 40–100 cm soil horizon. The latter not only directly enhanced NPP, but also indirectly promoted NPP by facilitating ET. In context of drought and water deficit, maintaining adequate soil moisture in the 40–100 cm layer through irrigation emerges as a potential strategy to ensure sustainable productivity. ET exerted the greatest comprehensive effect and the largest direct promotion on NPP. LAI, FAPAR, and SWC induced NPP variation indirectly through affecting ET. These consistently underscored the major relationship between productivity and water use. Future intensive agriculture in the NCP should prioritize the trade-off between carbon sequestration and water loss at plant physiological level. Improving the carbon sequestration per unit of water consumption through optimizing the photosynthesis-transpiration mechanism is an imperative climate-adaptative pathway for achieving sustainable food provision and mitigating water crisis.

Hyperspectral reflectance and agro-physiological traits for field identification of salt-tolerant wheat genotypes using the genotype by yield*trait biplot technique.

Salinity is the abiotic obstacle that diminishes food production globally. Salinization causes by natural conditions, such as climate change, or human activities, e.g., irrigation and derange misuse. To cope with the salinity problem, improve the crop environment or utilize crop/wheat breeding (by phenotyping), specifically in spread field conditions. For example, about 33 % of the cropping area in Egypt is affected by salinity. Therefore, this study evaluated forty bread wheat genotypes under contrasting salinity field conditions across seasons 2019/20 and 2020/21 at Sakha research station in the north of Egypt. To identify the tolerance genotypes, performing physiological parameters, e.g., Fv/Fm, CCI, Na+, and K+, spectral reflectance indices (SRIs), such as NDVI, MCARI, and SR, and estimated salinity tolerance indices based on grain yield in non-saline soil and saline soil sites over the tested years. These traits (parameters) and grain yield are simultaneously performed for generating GYT biplots. The results presented significant differences (P≤0.01) among the environments, genotypes, and their interaction for grain yield (GY) evaluated in the four environments. And the first season for traits, grain yield (GY), plant height (PH), harvest index (HI), chlorophyll content index (CCI), chlorophyll fluorescence parameter Fv/Fm, normalized difference vegetation index (NDVI) in contrasting salinity environments. Additionally, significant differences were detected among environments, genotypes, and their interaction for grain yield along with spectral reflectance indices (SRIs), e.g., Blue/Green index (BIG2), curvature index (CI), normalized difference vegetation index (NDVI), Modified simple ratio (MSR). Relying on the genotype plus genotype by environment (GGE) approach, genotypes 34 and 1 are the best for salinity sites. Genotypes 1 and 29 are the best from the genotype by stress tolerance indices (GSTI) biplot and genotype 34. Genotype 1 is the best from the genotype by yield*trait (GYT) method with spectral reflectance indices. Therefore, we can identify genotype 1 as salinity tolerant based on the results of GSTI and GYT of SRIs and recommend involvement in the salinity breeding program in salt-affected soils. In conclusion, spectral reflectance indices were efficiently identifying genotypic variance.

GIS-Facilitated Germination of Stored Seeds from Five Wild-Growing Populations of Campanula pelviformis Lam. and Fertilization Effects on Growth, Nutrients, Phenol Content and Antioxidant Potential

This study was designed to bridge extant research gaps regarding the vulnerable and protected local endemic Campanula pelviformis, a wild edible green traditionally consumed in Crete (Greece) with agro-alimentary and medicinal interest as well as ornamental value. The C. pelviformis ecological profile was generated using the climate and temperature conditions prevailing in its wild habitats through mapping of natural distribution linked with online bioclimatic databases in geographical information systems. We tested the germination of seeds from five wild-growing populations at four different temperatures (10, 15, 20 and 25 °C) and under different light conditions (light/dark and darkness), and we performed fertilization trails [integrated nutrient management (INF), chemical fertilization (ChFe), control] examining morphological and physiological characteristics, above- and below-ground macro- and micronutrients and phenol contents, as well as their antioxidant capacity. We found population and temperature effects on seed germination with their interaction being statistically significant. Campanula pelviformis germinated better at 10 and 15 °C (>85% for all populations) with no preference on light conditions (98.75% and 95% in light and dark conditions). The INF application increased root dry mass, chlorophyll content index and chlorophyll fluorescence compared to other treatments and was beneficial for macro- and micronutrient concentrations in above-ground parts compared to previously studied wild-growing material, while below-ground parts were positively impacted by both fertilization types. Total phenols and antioxidant capacity were both increased by ChFe fertilization. The data furnished herein permitted the re-evaluation and upgrade of its sustainable exploitation potential in different economic sectors.

Impact of soil moisture stress during the silk emergence and grain-filling in maize.

Suboptimal soil moisture during the growing season often limits maize growth and yield. However, the growth stage-specific responses of maize to soil moisture regimes have not been thoroughly investigated. This study investigated the response of maize to five different soil moisture regimes, that are, 0.25, 0.20, 0.15, 0.10, and 0.05 m3 m-3 volumetric water content (VWC), during flowering and grain-filling stages. Sub-optimal soil moisture at the flowering and grain-filling stages reduced ear leaf stomatal conductance by 73 and 64%, respectively. An increase in stress severity caused significant reductions in ear leaf chlorophyll content and greenness-associated vegetation indices across growth stages. Fourteen days of soil moisture stress during flowering delayed silk emergence, reduced silk length (19%), and silk fresh weight (34%). Furthermore, sub-optimal soil moisture caused a significant reduction in both kernel number (53%) and weight (54%). Soil moisture stress at the flowering had a direct impact on kernel number and an indirect effect on kernel weight. During grain-filling, disruption of ear leaf physiology resulted in a 34% decrease in kernel weight and a 43% decrease in kernel number. Unlike grain-filling, treatments at the flowering significantly reduced kernel starch (3%) and increased protein by 29%. These findings suggest that developing reproductive stage stress-tolerant hybrids with improved resilience to soil moisture stress could help reduce the yield gap between irrigated and rainfed maize.

Sustainable management practices for durum wheat production: Analyzing specific agronomic interventions on productivity, grain micronutrient content, and quality

As compared with single agronomic crop management practices during grain formation, knowledge about integrated agronomic management practices on grain mineral composition and grain technological properties in durum wheat is limited. This knowledge is important for determining management strategies aimed at increasing grain yield without affecting grain nutritional quality. Integrated agronomic practices such as foliar nutrient application × seeding rate × varieties combined with growing locations were investigated to evaluate the dynamics of yield and grain quality traits. Two durum wheat varieties, three-level of micronutrients (i.e. control, FeSO4, and ZnSO4), and four levels of seeding rate (i.e. 100, 125, 150, and 175 kg ha−1) were arranged in split-split plot design under two different growing locations (environments). The main plots were assigned to the varieties, subplots to micronutrients, and sub-sub plots to the seeding rate treatments. Zinc and iron were applied in a form of ZnSO4 and FeSO4 at the early flowering stage, both at a rate of 25 kg ha−1. Results showed a linear increment in biomass (21.5%) and grain yield (23.5%) under a high seeding rate, even though the 1000-grain weight, the number of grains spike−1, spike length, and the number of grains spike−1 were decreased. Higher varietal and environmental response of seeding rate was observed between varieties. The grain protein content, gluten, and zeleyn index decreased as the seeding rate increased. Grain micronutrient content was significantly influenced by seeding rate and varietal difference. The grain protein content was higher in a dryland environment than in a wet environment. A combined use of density-tolerant varieties, high seeding rate, and foliar-based iron application can improve the grain yield from 2.01 to 3.20 t ha−1 under a potential environment. Hence, all stakeholders should consider the genotype (G), environment (E), management (M), and their synergies, as far as grain yield and quality are considered simultaneously.

Modeling TEC Irregularities in the Arctic Ionosphere Using Empirical Orthogonal Function Method

AbstractWe develop a climatological model for the Arctic ionosphere based on more than one solar cycle of data (2010–2021) of the rate of change of the total electron content index (ROTI) maps from the International GNSS Service (IGS). The IGS ROTI maps are daily averaged in magnetic latitude and local time coordinates. To develop a climatological model, the ROTI maps are decomposed into base functions and coefficients using the empirical orthogonal function (EOF) method. The EOF method converges very quickly, and the first four EOFs reflect the majority (96%) of the total data variability. Furthermore, different EOF components can reflect different drivers of ionospheric irregularities. The first EOF reflects the averaged ROTI activity and the impact of the solar radiation and geomagnetic activity; the second EOF reflects the impact of the interplanetary magnetic field (IMF) Bz and electric field; the third and fourth EOFs reflect the dawn‐dusk asymmetry around the auroral oval and polar cap, and they can be related to the IMF By. To build an empirical model, we fit the EOF coefficients using helio‐geophysical indices from four different categories (solar activity; geomagnetic indices; IMF; the solar wind coupling function). The final EOF model is dependent on seven selected indices (F10.7P, Kp, Dst, Bt, By, Bz, and EKL). The statistical data‐model comparisons show satisfactory results with a good correlation coefficient. However, the model cannot capture the significant expansion of the dayside ROTI activity during strong geomagnetic storms. Future effort is needed to provide corrections to the model during severe storms.

Preferred Selection of Fractured Sweet Spot Section for Horizontal Shale Oil Well in West 233 Area

Six parameters, which can effectively reflect the reservoir quality and the completion quality, have been selected, including the sand structure index, the physical parameters, the oil content index, the brittleness index reflecting, the stress difference coefficient and the fracture pressure. The evaluation index of fracturing sweet spots in shale oil horizontal wells was constructed, and the fracturing sweet spot selection criteria for shale oil horizontal wells in the study area were established. Combined with dynamic production data, the fracturing sweet spots were classified into Class I (high quality reservoir), Class II (secondary reservoir) and Class II (non-fracturing sweet spot), which provided technical support for the preferential selection of fracturing formations in shale oil horizontal well.

Revisiting the Variation of the Ionospheric Irregularities in the Low Latitude Region of China Based on Small Regional Geodetic GNSS Station Network

AbstractThe rate of total electron content index (ROTI) and loss of lock (LoL) from global navigation satellite system (GNSS) observations are an important data source for ionospheric scintillation study. However, there are certain limitations of these data in ionospheric scintillation study, and clearing these limitations is important to understand the results from these data. In this paper, the variation of the ionospheric scintillation is revisited based on LoL and ROTI from a spatial dense GNSS network in the low latitude region of China. Via a priori knowledge of scintillation morphology, the method to determine the baseline ROTI for discriminating quiet and disturbed conditions is provided, and the abnormal data of ROTI and LoL unrelated to ionosphere are found and eliminated. Results show that the data examination is necessary. Using the qualified ROTI and LoL, the morphological variations of ionospheric irregularities are revisited. The temporal variation of ROTI and LoL are generally consistent, but there are some discrepancies. The maximum LoL occurrence is at about 21:00 LT, it is between 20:00 and 23:00 LT for ROTI. For spatial distribution, both parameters reach maximum occurrence in the southwest direction, but LoL is more concentrated. The azimuth range of maximum occurrence is 180–190° for LoL and 210–220° for ROTI. Statistically, the correlation between LoL occurrence and ROTI value from observation of single GNSS station is relatively good when ROTI <5 TECU/min, but it becomes worse when ROTI >5 TECU/min. However, their correlation can be greatly improved when data are averaged among all the stations.

The Impact of Molybdenum Mining on Cd Pollution along Wenyu Stream in Qinling Mountains, Northwest China

Mining has brought many environmental problems to the surrounding soil, water, and air, with toxic elements contaminating surface water, threatening ecological balance and human health. This study selected the Wenyu watershed downstream from a large molybdenum mine in the Qinling Mountains as the study area, aiming to explore the impact of molybdenum mining on surface water quality. The content characteristics of Cd, Pb, Cu, Cr and Hg in surface water, sediment, and rock samples were analyzed by field sampling and chemical testing. The results showed only obvious Cd pollution. The pollution status and ecological risk level of surface water and sediment samples in the Wenyu Stream watershed were evaluated using the single pollution index method, geo-accumulation index method, and Hakanson potential ecological risk assessment method. Finally, the sources of Cd pollution and the impact of mining on Cd distribution in the Wenyu Stream were comprehensively discussed. The research results showed that Cd content in the Wenyu Stream was significantly affected by mining activity and the coefficient of variation of Cd content reached 99.44%. Among 22 surface water samples, 21 samples met the Class II water standard, indicating a clean overall water quality of the Wenyu Stream, and only one sample exceeded the Class II water standard with a mild pollution level. All 15 sediment samples were polluted to varying degrees and the most severely polluted sample had reached a moderate to strong pollution level. Most of the samples were at a moderate pollution level. The potential ecological hazard indexes of Cd content were at medium to very strong risk level, indicating that the overall sediment in the main ditch of the Wenyu Stream was under a strong ecological risk level. The main sources of Cd pollution, including acid mine drainage, regional geological background, sediment release, and atmospheric dry and wet deposition, were discussed.

From urine to food and oxygen: effects of high and low NH4+:NO3- ratio on lettuce cultivated in a gas-tight hydroponic facility.

In situ production of food, water and oxygen is essential for long-duration human space missions. Higher plants represent a key element in Bioregenerative Life Support Systems (BLSS), where crop cultivation can be based on water and nutrients recovered from waste and wastewater. Human urine exemplifies an important waste stream with potential to provide crops with nitrogen (N) and other nutrients. Dynamic waste composition and treatment processes may result in mineralized fractions with varying ammonium (NH4 +) to nitrate (NO3 -) ratios. In this study, lettuce was cultivated in the unique ESA MELiSSA Plant Characterization Unit, an advanced, gas-tight hydroponic research facility offering controlled environment and continuous monitoring of atmospheric gas composition. To evaluate biological and system effects of nutrient solution NH4 +:NO3 - ratio, two crop tests were run with different NH4 + to total N ratio (NH4 +:N) and elevated concentrations of Na+ and Cl- in line with a urine recycling scenario. Plants cultivated at 0.5 mol·mol-1 NH4 +:N (HiNH4 +) achieved 50% lower shoot biomass compared to those cultivated at 0.1 mol·mol-1 NH4 +:N (LoNH4 +), accompanied by higher shoot dry weight content and lower harvest index. Analyses of projected leaf area over time indicated that the reduced biomass observed at harvest could be attributed to a lower specific growth rate during the close-to-exponential growth phase. The HiNH4 + crop produced 40% less O2 over the full cultivation period. However, normalization of the results indicated a marginal increase in O2 production per time and per projected leaf area for the HiNH4 + crop during the exponential growth phase, in line with a higher shoot chlorophyll content. Mineral analysis demonstrated that the biomass content of NH4 + and NO3 - varied in line with the nutrient solution composition. The ratio of consumed NH4 + to consumed N was higher than the NH4 +:N ratio of the nutrient solution for both crop tests, resulting in decreasing NH4 +:N ratios in the nutrient solution over time. The results provide enhanced insight for design of waste processes and crop cultivation to optimize overall BLSS efficiency and hold valuable potential for improved resource utilization also in terrestrial food production systems.

Characterizing of Sandy Loam Soil Electrical Conductivity and Cone Index Relationship at Varying Depths in Punjab Region

Soil constitutes a fundamental resource for the production of food and fiber, thereby meeting diverse human needs and sustaining global ecosystems. Soil compaction and electrical conductivity are key soil properties that can significantly impact soil health and contribute to environmental challenges. The findings of the study shed light on the severity of soil compaction, with the highest cone index 4495 kPa value recorded at a depth of 225 mm in sandy loam soil. This highlights the potential limitations on root growth and nutrient uptake, which can have implications for plant productivity and the overall ecosystem. Furthermore, the study examined the electrical conductivity of the soil, which serves as an indicator of soil salinity. Elevated electrical conductivity levels can lead to adverse effects such as reduced crop yields and environmental stress. Bulk density was increased (1.4 to 1.73 Mg/m3) as well as the moisture content of the soil was decreased (7.6 to 4.3 %). Understanding the range of electrical conductivity values observed in the study (11 to 29 mS/m) helps to assess the extent of salinity-related challenges in the studied region. By establishing regression equations between cone index and soil properties like bulk density and moisture content, the study provides valuable insights into the underlying relationships that contribute to soil compaction and its environmental implications. The coefficient of determination (R2) between the bulk density with moisture content and cone index was 0.99 and 0.95, respectively. These findings can assist in the development of strategies to mitigate soil degradation, promote sustainable land management practices, and address environmental concerns related to soil health.

Simulation of Soil Water and Nitrogen Dynamics for Tomato Crop using EU-Rotate_N Model at Different Nitrogen Levels in the Greenhouse

To pursue high yields, the excessive application of nitrogen (N) fertilizer has been reported in high-residual soil nitrate levels, excessive nitrate leaching, and nitrate contamination of groundwater. In this study, tomato crops (Lycopersicon esculentum Mill.) were subjected to various nitrogen treatments, and the nitrate nitrogen content, soil water content at different soil layers, dry matter, and yield were measured. A mechanistic model, EU-Rotate_N, was used to simulate the aforementioned indexes in a region of Jiangsu province with a relatively higher water table. The predicted values of soil moisture and soil nitrate content at various soil depths agree well with the measured values during tomato growth. The statistical index of soil water content ranged from 0.367 to 0.749, 0.856 to 0.947, and the statistical index of soil nitrate nitrogen content ranged from 0.365 to 0.698, and 0.869 to 0.932, for Autumn-Winter (AW) and Spring-Summer (SS) crops, respectively. Moreover, the dry weight and yield simulation effects of the tomato are also in good agreement with the actual measured values. The results show that the EU-Rotate_N model is effective in simulating soil water content, nitrate nitrogen content, dry matter quality, and yield in Jiangsu province, with little underestimation in soil water content at a soil depth of 20–30 cm during SS, which might be improved further considering the high water table of the region.

An Analysis of Pediatric Ophthalmology Content on TikTok.

To assess pediatric ophthalmology-related information on TikTok (ByteDance). The 12 most commonly searched terms from the American Association for Pediatric Ophthalmology and Strabismus website were queried as TikTok hashtags. The top 20 videos for each hashtag were analyzed for views, likes, comments, saves, shares, author status and gender, content, and engagement level ratio (ELR). Subanalysis of the educational videos for quality, understandability and actionability, and medical accuracy using the modified DISCERN (mDISCERN), Patient Education Materials Assessment Tool (PEMAT), and modified Medical Information and Content Index (mMICI) was performed. Analysis of 222 videos revealed a cumulative 191,337,973 views. Patients/families created the most videos (60.4%), followed by optometrists (14.4%), other (laypeople/unknown) (9.0%), ophthalmologists (7.7%), non-ophthalmology physicians (4.5%), and nurses (4.1%). Content was predominantly patient experience (56.8%), followed by educational (25.2%), humor (11.7%), self-promotional (3.6%), procedures (0.9%), other (0.9%), advertisements (0.5%), and career (0.5%). Educational videos had a lower ELR than humorous (3.3 vs 8.2, P < .001) and patient experience (3.3 vs 5.3, P < .001) videos, but more saves than patient experience videos (74 vs 25, P = .009). The mDISCERN scores were greater for videos authored by ophthalmologists (3, P < .001) and optometrists (2.5, P < .001) compared to lay-people (1.5). Ophthalmologist PEMAT understandability scores were greater than non-ophthalmology providers' (95.5% vs 67.4%, P = .002). There was no difference in PEMAT actionability (P = .743) or mMICI scores among the author subgroups (P = .206). Pediatric ophthalmology content on Tik-Tok ranges in quality and understandability. Additional research is needed to help promote posts created by eyecare providers to ensure evidence-based medical content reaches pediatric patients and their families. [J Pediatr Ophthalmol Strabismus. 2024;61(2):90-97.].

Contrasting dissolved organic matter biodegradation and bacterial cytometric features in oligotrophic and ultraoligotrophic Patagonian lakes

Abstract Biodegradation process of dissolved organic matter (DOM) could be affected by its concentration and quality. Two biodegradation experiments were conducted in two contrasting seasons in two oligotrophic and one ultraoligotrophic temperate lakes, which comprise a natural gradient of dissolved organic carbon (DOC) concentration and quality (including lakes of &amp;lt; 83.33 μM). We examined associations between biodegradation and bacterial cytometric descriptors (i.e. abundance, DNA relative content, etc.) and with different DOM characteristics. The biolabile DOC (BDOC) was higher in shallow oligotrophic lakes, which displayed higher DOC concentration than the deep ultraoligotrophic one. The BDOC was mainly relatable not only to DOC concentration but also with DOM quality [fluorescent terrestrial-humic component normalized by DOC (C2:DOC), lignin content (a*350) and biological index]. We found a positive association between biodegradation process and high nucleic acid–content bacterial group. The bacterioplankton cytometric features were shaped by DOM concentration and quality along the biodegradation process. We concluded that in oligotrophic lakes, DOC concentration was the main driver of BDOC, whereas in ultraoligotrophic lakes, DOM quality played a more central role. This study contributes to better understand the biodegradation process in pristine low-DOC lakes with natural variation in allochthonous DOM inputs and with implications in the biogeochemical cycles.

Petrogenesis of the Yunling Sn-rich magma in the Baoshan Block, SW China: Constraints from mineral and whole-rock geochemistry

Southwest Yunnan is one of the most important tin (Sn) metallogenic belts in China. The Sn mineralization is mainly linked with the Cretaceous and Cenozoic magmatism. Triassic granitoids are also widely developed in this region, where the Yunling granitoids are considered to represent an essential target for the localization of Sn mineralization. However, the source characteristics of these ore-related granitoids are still unclear. Here we present geochronology, petrology, and mineral geochemistry to reveal the petrogenesis of Sn-rich magma. Zircon U-Pb dating indicates that the Yunling samples were emplaced at 220–209 Ma, suggesting that the Late Triassic magmatism in the Yunling district along the S–N trending Changning-Menglian suture zone (CMSZ) was generated at the post-collisional stage. Samples from the Yunling pluton exhibit a variable SiO2 content of 54.8–68.5 wt% and are characterized by a high normative corundum content (>1 wt%) and aluminum saturation index (A/CNK = 0.84–1.17). Systemic zircon geochemistry suggests that these samples belong to S-type granite. Moreover, the granitoids have extremely enriched Nd-Hf isotopic signatures with εNd(t) values of −11.5 to −10.7 and εHf(t) values of −21.6 to −10.6. These findings, together with the elevated Ba/Pb ratios and high zircon Ti temperatures (≥800 °C), indicate that the Yunling S-type granitoids were likely to have been derived from the dehydrating partial melting of biotite in the metasedimentary rocks at high temperatures. In addition, the magmatic oxygen fugacity obtained from the magmatic accessory minerals suggests that the ore-related granitic magmas are highly reduced, with the estimated ΔFMQ (fayalite-magnetite-quartz buffer) generally ranging from −5.45 to −0.22 (-3.48 on average). Based on these results, we conclude that the decomposition of biotite in the source effectively extracted Sn, thus forming initial Sn-rich melts which crystallized and differentiated at a low oxygen fugacity and were eventually deposited in the shallow crust to form the Yunling Sn-bearing granitoids.