Influence Of Soil Characteristics Research Articles

Mineral composition variation in Boletales mushrooms—indication of soil properties and taxonomic influence

The efficiency of element accumulation depends on numerous factors, where the physico-chemical characteristics of the soil seem to be very important, and the role of taxonomic rank in the accumulation of elements by mushrooms seems to be important. The aim of the study was to compare the mineral composition of 7 species belonging to Leccinum and Suillus genera, collected between 2019 and 2021 from localizations in the west-central part of Poland. The research aimed to indicate the role of selected soil parameters in stimulating/inhibiting the accumulation of elements by selected Boletales mushroom species and to answer the question about the role of species belonging to the genus as an indicator determining the specific mineral composition of fruiting bodies. Soil pH and other soil properties (granulometric composition, organic carbon, degree of organic matter decomposition) may significantly affect mushrooms' mineral composition. Mushroom species belonging to Leccinum genus exhibited the higher amount of essential major and trace elements than species of Suillus genus). It suggests that the affiliation of the studied mushroom species to a specific genus may affect their mineral composition, and the physicochemical properties of the soil may be responsible for the lack of a clear division in the efficiency of element(s) accumulation. Selected species contain high amounts of K, Cu, Fe, and Zn, while others, such as selected Suillus gravellei fruiting bodies, also contain As and Cd. The results described serve as an introduction to a broader scientific discussion and require many further studies to confirm the role of taxonomic ranks and the influence of soil characteristics on the accumulation of elements by fruiting bodies.Graphical

Influence of soil characteristics on the concentrations of Cr, Pb, and Zn in tobacco leaves from Longyan, China, and the associated predictive models

In Longyan City, Fujian Province, a hub for premium tobacco in China, our study explored the connection between soil properties and heavy metal levels in tobacco leaves, focusing on chromium (Cr), lead (Pb), and zinc (Zn). We observed that the soil’s average concentrations for Cr, Pb, and Zn were 0.165, 9.53, and 5.17 mg kg−1, respectively. In stark contrast, tobacco leaves presented elevated mean concentrations of these metals, measuring 0.936, 2.19, and 102 mg/kg for Cr, Pb, and Zn, respectively. This disparity was further highlighted by the soil’s exceedance rates for Pb and Zn at 2.93% and 0.472%, and the significantly higher enrichment coefficients in tobacco, 23.1 for Pb and 19.7 for Zn, compared to Cr, suggesting a substantial health risk. Our study identified critical soil parameters, including pH, organic matter, and levels of available potassium and phosphorus, as influential factors determining heavy metal content in tobacco. Utilizing these findings, we formulated predictive regression models for estimating Cr, Pb, and Zn concentrations in tobacco leaves. The regression models for estimating the concentrations of chromium, lead, and zinc in tobacco leaves are as detailed below: YCr = 0.889 + 0.001 * XK + 0.001 * XN − 0.005 * XOM + 0.101 * XCr (R2 = 0.852), YPb = 2.608–0.069 * XpH − 0.001 * XN + 0.008 * XZn + 0.01 * XPb (R2 = 0.738) and YZn = 101.892–0.141 * XP + 0.32 * XOM − 0.123 * XPb + 0.614 * XZn (R2 = 0.801), respectively. These offering essential tools for assessing and controlling heavy metal risks in tobacco cultivation within the region.

Investigating the effects of APSIM model configuration on model outputs across different environments

IntroductionSoil type plays a major role in nutrient dynamics and soil water which impacts crop growth and yield. The influence of soil characteristics on crop growth is usually evaluated through field experimentation (in the short term) and through crop-soil modelling (in the long-term). However, there has been limited research which has looked at the effect of model structural uncertainty of model outputs in different soil types.MethodsTo analyze the impact of soil inputs on model structural uncertainty, we developed eight model structures (a combination of two crop models, two soil water models and two irrigation models) within the Agricultural Production Systems sIMulator (APSIM) across three soil types (Ferralsols, Alisols and Chernozems). By decomposing the mean proportion of variance and simulated values of the model outputs (yield, irrigation, drainage, nitrogen leaching and partial gross margin) we identified the influence of soil type on the magnitude of model structural uncertainty.ResultsFor all soil types, crop model was the most significant source of structural uncertainty, contributing >60% to variability for most modelled variables, except irrigation demand which was dominated by the choice of irrigation model applied. Relative to first order interactions, there were minimal (<12%) contributions to uncertainty from the second order interactions (i.e., inter-model components). We found that a higher mean proportion of variance does not necessarily imply a high magnitude of uncertainty in actual values. Despite the significant impact of the choice of crop model on yield and PGM variance (contributing over 90%), the small standard deviations in simulated yield (ranging from 0.2 to 1 t ha-1) and PGM (ranging from 50.6 to 374.4 USD ha-1) compared to the mean values (yield: 14.6 t ha-1, PGM: 4901 USD ha-1) indicate relatively low actual uncertainty in the values. Similarly, the choice of irrigation model had a contribution of over 45% to variance, but the relatively small standard deviations ranging from 11 to 33.3 mm compared to the overall mean irrigation of 500 mm suggest low actual uncertainty in the values. In contrast, for the environmental variables- drainage and nitrogen leaching, the choice of crop model had contributions of more than 60% and 70% respectively, yet the relatively large standard deviations ranging from 7.1 to 30.6 mm and 0.6 to 7.7 kg ha-1 respectively, compared to the overall mean values of drainage (44.4 mm) and nitrogen leaching (3.2 kg ha-1), indicate significant actual uncertainty.DiscussionWe identified the need to include not only fractional variance of model uncertainty, but also magnitude of the contribution in measured units (e.g. t ha-1, mm, kg ha-1, USD ha-1) for crop model uncertainty assessments to provide more useful agronomic or policy decision-making information. The findings of this study highlight the sensitivity of agricultural models to the impacts of moisture availability, suggesting that it is important to give more attention to structural uncertainty when modelling dry/wet conditions depending on the output analyzed.

Shaking table test study of nuclear power plant model considering soil-structure interaction effect

The influence analysis of site condition is fundamental to the seismic design of nuclear power plants. In this paper, a series of shaking table tests were performed to investigate the Soil-Structure Interaction (SSI) effect on the seismic response of nuclear power structures. An AP1000 nuclear power plant was taken as the objective structure, lead rubber bearings (LRBs) were used as the isolators and Shanghai silty clay was selected as the model soil. Test results show that (1) The soil has different effects on the dynamic characteristics of isolated and non-isolated model structures. (2) During the shaking table test, the foundation edge is subject to the highest soil pressure, and a contact surface separation between the foundation and the soil begins to occur under the seismic-margin earthquake (SME) seismic input level. (3) Both for the rigid and soil foundation, seismic isolation bearings can effectively reduce the acceleration response of the superstructure. (4) For the non-isolated model, the SSI effect significantly amplifies the seismic response at the bottom floor of the structure in the low frequency range, and an obvious rocking behavior occurs at the operating basis earthquake (OBE) seismic input level. (5) For the isolated model, the SSI effect reduces the hysteresis capacity of the seismic isolation system and amplifies the seismic response at the bottom floor, especially in the vertical direction. The site condition and the use of an isolation system have a significant impact on the seismic response of a nuclear power structure. Therefore, in the design and safety assessment of nuclear power plants, the influences of soil characteristics and isolation equipment in the soil-structure interaction system should be fully considered.

Phosphomonoesterases Activity in Phosphorus-fertilized and Mycorrhizae-inoculated Cassava’s Rhizosphere in Two Savanna Agro–ecologies of Nigeria

Rhizosphere is a bio–influenced zone of soil where the interaction of microorganism and plant roots occurred tailored by the activity of soil enzymes. The activity of the enzymes depends largely on the physical and chemical characteristics of the soil environment. Experiment was carried out to examine the activity of phosphomonoesterases in the rhizosphere of cassava planted in two sites (Samaru and Minjibir) located in savanna ecologies of Nigeria. Soils from rhizosphere of the cassava were sampled from each treatment in an experiment involving split plot design. The treatments included 3 main plots (phosphorus rates at 0, 17.5 and 35 kg P2O5 ha–1) and 3 sub–plots (mycorrhizal inoculants: Glomygel and Mycodrip; and a Control). The Result of the analysis indicated higher activities of the phosphomonoesterases (acid and alkaline phosphatases) in Samaru site than Minjibir. The former recorded higher acid and alkaline phosphates activities over the latter with a magnitude of 96.84% and 43.65% respectively. This is attributed to the variability in the soil characteristics between the two sites. The main effect of P fertilizer indicated that 0 kg P2O5 ha–1 recorded a significantly (p<0.05) higher phosphomonoesterases activity than application of 17.5 and 35 kg P2O5 ha–1. Inoculation with mycorrhizae also increased the activities of the phosphomonoesterases in both sites which indicate increase mycorrhizal colonization as a result of inoculation. It is concluded therefore, that the activity of phosphomonoesterases in the rhizosphere can be affected by fertilization as well as enhanced by inoculation with the influence of soil characteristics.

Ecological Distribution Patterns and Indicator Species Analysis of Climber Plants in Changa Manga Forest Plantation

Climbing plants have an important role in forest communities and ecosystems. Despite the significance of the climbers in ecosystems, most of the previous research work in Pakistan has been concentrated on trees, shrubs, and herbs, with little attention paid to climbing plants. The current study investigated the ecology of climbers and the influence of soil characteristics on diversity, richness, and indicator species distribution in the Changa Manga Forest Plantation, Punjab, Pakistan. Field surveys were carried out between 2020 and 2021, with the data gathered using a random sample approach for ordination and cluster analysis of each plant species and edaphic data from sample plots. We reported a total of 29 climber species belonging to 23 genera and 9 families from the area. The Convolvulaceae family was the most prevalent, followed by Apocynaceae and Cucurbitaceae. Herbaceous climbers were the typical life form (70% species) and species showed peak flowering during the months of August and September. The multivariate analysis and cluster analysis grouped the climbers into four distinct communities based on the indicator species, representing filtering of the species pool in the studied area. Canonical Correspondence Analysis (CCA) results showed that soil factors had a significant influence (p ≤ 0.002) on the climbers’ diversity and distribution pattern. Our research contributes to a deeper understanding of climbing plant ecology in response to soil variables, with immediate consequences for policy and practice in this Himalayan region, as well as research insights for neighboring Himalayan regions and elsewhere in the world.

Methodological Fundamentals of Information System Design in Crop Production

Introduction. The creation of new technologies for precision agriculture is intended to increase productivity, labor efficiency and improve production processes. According to the World Food Program (WFP), 811 million people are chronically hungry, 283 million are in a state of starvation or close to starvation. An estimated 45 million more in 43 countries around the world are on the brink of starvation. Today's conditions require agriculture to feed a planet with an ever-growing population, minimize costs, and develop technologies that do not pollute the planet. Therefore, modeling of biological objects, research and design of intelligent systems for agriculture are of great interest to scientists around the world today. The purpose of the paper is development of the main approaches to building a full-scale experiment from the point of view of planning methodology, data processing, and model selection. The methodical basics, principles and practical component of planning an experiment in crop production are disclosed. The results of the development of the automatic decision-making system and the basic mathematical models for the construction of the information system are presented. Results. The basis of the study of the plant organism is a natural experiment. Field experiments in crop production are difficult to reproduce and face a number of difficulties related to the accuracy of the research methods used, which consist in the reliability and accuracy of the measurement results. For the first time, a multi-level information system for monitoring the condition and needs of plants, which contains a wireless sensor network, an ontologically controlled node, a global database, a knowledge base, an explanatory module, a control module, a computer, and a human-machine interface, which allows taking management decisions, was used for the research. decision. Our algorithm system is able to take into account the variability of changes in a multivariate environment. An information system where the chlorophyll fluorescence induction parameter, induction, measured in real time, acts as a control module. This is a promising way of adjusting irrigation regimes, monitoring the condition of plants and caring for perennial plantations. Conclusions. An important part of this work is the study of the effect of induction of chlorophyll fluorescence and the study of the methodology of research on photosynthesis. This effect is very sensitive to many changes in the plant. This is an advantage of the method and is a requirement for the research methodology or the specifics of its conduct. The study of plant objects faces a number of difficulties. Of special interest is the composition of the soil and the influence of soil characteristics on the growth and development of plants, for the creation of profile soil maps. Due to the fact that the plant object is not only a collection of individual systems inside the organism, but is also exposed to the constant influence of external factors of the environment, climate and soil, which must be taken into account when creating new information systems, the purpose of which is to increase productivity. Keywords: wireless sensor network, methodology, biosensors, information system, mathematical model, agriculture, plant physiology.

Uptake, Accumulation, and translocation of azoxystrobin by Vegetable plants in soils: influence of soil characteristics and plant species.

Although azoxystrobin has been widely applied on various crops, little is known about the bioavailability of azoxystrobin in the soil-vegetable system. In this study, the uptake, accumulation and translocation of azoxystrobin as affected by soil characteristics and plant species were respectively investigated. The accumulation amount of azoxystrobin in pakchoi increased as soil adsorption decreased and was positively associated with its concentration in pore water (Cpw), which was mainly affected by soil organic matter content. Therefore, Cpw could be a candidate for the estimation of azoxystrobin accumulation in pakchoi. In all the tested vegetables, azoxystrobin was mainly accumulated in roots, and its upward translocation was limited. Root lipid content was a major factor affecting the uptake and translocation of azoxystrobin in different vegetables.

Influence of Soil Characteristics on the Growth of Poplar Short Rotation Coppice (SRC) under Suboptimal Conditions

Several studies have discussed the growth of poplar short rotation coppices (SRC). Soil characteristics have a large effect on the yields of sites with no access to surplus water sources – especially on their physical and chemical properties contributing to water storage, all of which limit growth. We conducted our research on a fourth rotation plantation established with two different poplar clones (‘AF2’ and ‘Kopecky’) on a site without groundwater in the rooting zone to describe the influence of topography and soil parameters on biomass production. For both hybrids, 5–5 sample areas were planted. Systematic soil sampling, a tree inventory, and a destructive tree survey were completed to provide an equation of site and clone specific biomass estimation. Our results revealed that the shallower, eroded areas presented low-yield patches, particularly when compared to the parts with deeper rooting zones and soil richer in mineral and organic colloids. The amount of the plant available water, pH value, organic matter content, and CaCO3 content have the most significant effect on growth. No meaningful growth difference emerged between the two clones. The previously mentioned soil properties greatly influence tree growth on sites with no direct access to the groundwater; therefore, a detailed site description is indispensable for plantation planting.

Zinc Plant Uptake as Result of Edaphic Factors Acting.

The influence of soil characteristics on the lability and bioavailability of zinc at both background and phytotoxic concentrations in Albic Retisol soil (Loamic, Ochric) was studied using various methods. Ranges of insufficient, non-phytotoxic, and phytotoxic zinc concentrations in soil solutions were established in an experiment with an aqueous barley culture. It was experimentally revealed that for a wide range of non-toxic concentrations of Zn in the soil corresponding to the indicative type of plant response, there was constancy of the concentration ratio (CR) and concentration factor (CF) migration parameters. As a result, a new method for assessing the buffer capacity of soils with respect to Zn (PBCZn) is proposed. The transformation processes of the chemical forms and root uptake of native (natural) zinc contained in the Albic Retisol (Loamic, Ochric) through the aqueous culture of barley were studied using a cyclic lysimetric installation and radioactive 65Zn tracer. The distribution patterns of Zn(65Zn) between different forms (chemical fractions) in the soil were established using the sequential fractionation scheme of BCR. The coefficients of distribution and concentration factors of natural Zn and 65Zn, as well as accumulation and removal of the metal by plants were estimated. The values of the enrichment factor of natural (stable) Zn contained in sequentially extracted chemical fractions with the 65Zn radioisotope were determined and the amount of the pool of labile zinc compounds in the studied soil was calculated.

Influence of soil characteristics and metal(loid)s on antibiotic resistance genes in green stormwater infrastructure in Southern California

The synergetic effects of metal(loid)s and soil characteristics on bacterial antibiotic resistance genes (ARGs) in green stormwater infrastructure (GSI) has been relatively understudied. Surface soil samples from six GSIs in Southern California over three time periods were assessed for selected ARGs, class 1 integron-integrase genes (intI1), 16S rRNA genes, and bioavailable and total concentrations of nine metal(loid)s, to investigate the relationships among ARGs, soil characteristics, and co-occurring metal(loid)s. Significant correlations existed among relative gene abundances (sul1, sul2, tetW, and intI1), total metal(loid)s (arsenic, copper, lead, vanadium, and zinc), and bioavailable metal(loid) (arsenic) (r = 0.29–0.61, padj < 0.05). Additionally, soil texture, organic matter, and nutrients within GSI appeared to be significantly correlated with relative gene abundances of sul1, sul2, and tetW (r = −0.57 to 0.59, padj < 0.05). Multiple regression models significantly improved the estimation of ARGs in GSI when considering multiple effects of soil characteristics and metal(loid)s (r = 0.74, padj < 0.001) compared to correlation results. Total arsenic was a significant (positive) correlate in all the regression models of relative gene abundances. This work provides new insights into co-dependencies between GSI ARGs and co-occurring metal(loid)s, indicating the need for risk assessment of metal(loid)-influenced ARG proliferation.

Influence of soil quality factors on capsaicin biosynthesis, pungency, yield, and produce quality of chili: An insight on Csy1, Pun1, and Pun12 signaling responses

Hotness or pungency is the major trait of genetically diverse and economically valuable chili (Capsicum sp.) cultivars. However, little is known about the influence of soil characteristics on genetic regulation of pungency vis-à-vis capsaicin formation in endemic chilies. Hence, the present work was conducted by growing two endemic chili cultivars in two types (alluvial and lateritic) of soil. Capsaicin content, pungency, and capsaicin synthase activity were significantly greater in chilies grown in alluvial soil than in lateritic soil. Correspondingly, Csy1, the gene that encodes capsaicin synthase, was significantly upregulated in alluvial soil grown plants. Interestingly, upregulation of Pun1, the gene responsible for capsaicin accumulation in fruits, was more in lateritic soil than in alluvial soil; but pungency was inhibited in lateritic soil by the overexpression of Pun12, a recessive allele of Pun1 locus. Statistical analyses revealed that high organic C, microbial activity, and NPK status in alluvial soil were responsible for high pungency, capsaicin synthase activity, capsaicin accumulation, and suppression of Pun12. Fruit yield, dry matter, crude protein, titratable acidity, and soluble solids were also significantly high in chilies grown in alluvial soil. Therefore, we postulate that soil quality attributes play vital roles in genetic regulation of pungency, capsaicin biosynthesis, fruit yield, and produce quality of endemic chili cultivars.

Influence of soil characteristics on working dynamics mining tral authority

The safest way to clear mines and barriers, in terms of saving human life and health, is to clear them at the site. Minesweepers are being used for this purpose, and in recent years they have gained extensive research, which is aimed at the use of large-scale explosion technology. Existing minesweepers in the Armed Forces of Ukraine, as a rule, are old-fashioned, and have certain shortcomings that affect the efficiency of their direct use. These include, first of all, insufficient survivability and different efficiency of their use during demining of minefields with different types of soils: from sandy, loamy and gravel. The range of physical and mechanical properties of the latter is very wide, and therefore - for the operation of an explosive device (mine) requires different amounts of action on the soil surface. The modernized mine trawl neutralizing device in the form of a system of U-shaped rockers with disks at the end is proposed in the work. They, acting directly on the mine, or through a small layer of soil, cause it to explode, provided that the force on the latter is not less than the minimum value required for its disposal. The advantage of this type of mine trawl is that even if one of the working disks fails during the explosion, it is structurally relatively easy to replace it with another. The magnitude of the deepening of the neutralizing disks into the soil (at a constant weight of the mounted part of the trawl), as well as their dynamic action through the soil on the mine depends on the physical and mechanical properties of the soil. Therefore, for the case of, for example, clay or sandy soils during the movement of the trawl, it will be sufficient for the operation of the explosive device, at the same time for the coating of gravel - insufficient. In addition, the amount of deepening of the working disks in the soil depends on its humidity.&#x0D; The study of the influence of the main physical and mechanical characteristics of soils on the dynamics of the modernized mine trawl neutralizing device during movement along the minefield (before and after the mine explosion) is the subject of research, hence their relevance.

Evaluation of Dittrichia viscosa (L.) Greuter Dried Biomass for Weed Management.

Dittrichia viscosa (L.) Greuter, a plant species common in the Mediterranean basin, produces several bioactive compounds, some of which have herbicidal effects. A number of greenhouse and field experiments were carried out in order to evaluate if these effects could be obtained also by using the whole plant biomass, to identify the efficacious doses, determine their effects on seed germination and weed emergence, and to evaluate influence of soil characteristics on biomass efficacy. The experiments carried out evidenced that: (i) the dried biomass completely hampers plant emergence when high doses (30–40 kg biomass m−3 of soil) are mixed into the soil, or delays it at a lower dose (10 kg m−3); (ii) the detrimental effects are not affected by soil type. The exploitation of the D. viscosa dried biomass appears to be a feasible option in weed management practices and its potential is discussed.

THE ANALYTICAL DETERMINATION OF THE PARAMETERS OF THE WELL WHILE ELIMINATING UNEQUAL SETTLEMENT OF FOUNDATIONS METHOD OF DRILLING-OUT OF THE SOIL

Existing approaches which allow to reduce the settlement unevenness of buildings and structures have their own advantages and disadvantages. One of the promising methods for reducing shallow foundations the settlement unevenness, which are based on soft dust and clay soil, is the building or its part lowering. The effect is achieved by drilling vertical wellbores in the immediate proximity to the existing foundation from the side of the least settlement. At different times, domestic and foreign scientists were engaged in to the methods of horizontal and inclined drilling of wellbores, an important issue, when applying this technology, is the determination of drilling parameters, the influence of soil characteristics and the stress state of the soil around the well, on the roll reduction process. The article considers the influence of the soil strength characteristics on the stress state of the soil which are surrounding the wellbore, and the effect of the drilled wellbore radius on the formation of the critical state regions. The analytical solution is based on the use of the well-known relationship for determining the stress state around the well during pressiometric tests. From this ratio, tangential and radial stresses are determined, which are then checked according to the condition of the law of strength, thereby forming a picture of the stress state around the well. According to the presented methodology, the stress state of the soil around the wells was calculated, which allows calculating the zones of soil destruction and thereby determining the parameters of the wells and the geometry of their location depending on the goals, when regulating the sediment of slab foundations.

Influence of Soil Characteristics on Wood Biodeterioration by Brown Rot Fungi

Soil conditions can directly influence the inoculum potential of wood decay fungi, which is likely to be a major factor in the premature failure of utility poles across Europe. The objective of our study was to assess the influence of soil pH, humic acid and iron on wood decay. For this purpose, we incubated Fe-impregnated wood specimens on artificial medium to evaluate the influence of the metal on the activity of brown rot fungi. Moreover, the impact of Cu-leaching from impregnated wood specimens that were exposed to humic acid solutions was measured. In addition, weight losses caused by brown rot fungi in impregnated wood pole segments and stiffness (Young’s modulus of Elasticity) of Cu-impregnated wood specimens were quantified. The pH measurements showed that the soil samples were slightly acid (pH = 6.7 ± 0.7). In comparison to non-impregnated controls, the Fe-impregnated samples significantly increased weight losses by brown rot fungi (&gt;30–40%). In the presence of humic acid the release of copper from chromium-free wood preservatives (up to 143.34 mg L−1) was enhanced. Weight losses in impregnated wood segments by brown rot fungi ranged from 5.3 to 20.4%. The recorded reduction in stiffness by brown rot fungi ranged from approximately 3.96 to 55.52% for Cu-impregnated wood specimens after 12 weeks. Our study shows that the pH, humic acid, iron content and selected wood preservatives greatly influence susceptibility of impregnated wood to brown rot fungi during ground contact.

Sample key features affecting mechanical, acoustic and thermal properties of a natural-stabilised earthen material

The use of natural materials has become more important as a result of the growing need to conserve energy, exploit renewable materials, and incorporate architecture and construction into sustainable methods of production. Accordingly, the present work investigates the engineering properties of a new earthen building material. This proposal is based on traditional unfired earthen masonry and consists of compressed earth blocks stabilised with natural polymers and wool fibers for use as insulating and structural load-bearing walls in buildings. The conducted experimental study enabled us to determine the mechanical performance, thermal conductivity, noise mitigation, modulus of elasticity, porosity percentage, and diameter through mercury intrusion porosimetry. The influence of soil characteristics on thermophysical and acoustic properties of tested material were investigated. The experimental data show good efficiency and a significant improvement in the engineering properties of these materials compared to traditional compressed earth blocks. In this research, a comprehensive analysis of the interaction of different properties is proposed as an assessment methodology that could be applied to any kind of stabilised soil material. The correlation of the results, being the type of soil the only variable of the analyzed samples, has allowed identifying sample key features and tests so as to obtain the best mechanical, thermal and acoustic performances.

Influence of soil characteristics on physiological and growth responses of Cytharexyllum myrianthum Cham. (Verbenaceae) to flooding

The success of watershed riparian forest restoration programs can be affected by the selection of plant species tolerant to flooding and soil types that occur along water courses. We evaluated physiological and growth responses of Cytharexyllum myrianthum seedlings to flooding in three different soil types representative of the Almada River Watershed (ARW), southern Bahia, Brazil. The soils selected, based on the relative abundance and importance in the ARW, were: Luvisol, Argisol, and Spodosol. After 35 days of flooding, the Argisol had the lowest and the Spodosol had the highest reduction–oxidation (redox) potential (Eh). After 35 days of flooding, the Luvisol had higher pH and electrical conductivity (Ec) than the other soils. Stomatal conductance (gs) and net photosynthesis (A) significantly declined in all soil types after 7 days of flooding. After that period, morphological changes characteristic of flood-tolerant plants, such as lenticel hypertrophy and adventitious root formation, were observed in all flooded plants. Following the morphological changes, gs and A in flooded plants increased to values close to those of the non-flooded plants. The highest relative growth rates based on mass (RGRm) and net assimilation rates (NAR) for the non-flooded plants were observed in the Argisol. After 35 days of flooding, no significant differences in RGRm or NAR were observed between non-flooded and flooded plants in the Luvisol, but large significant decreases in RGRm and NAR were observed for the flooded plants in the Spodosol. Our results demonstrated that the ability of seedlings of the same species to acclimate to flooded soil conditions differs among soil types. Therefore, the characteristics of soils present in a watershed should be considered when selecting tree species for the reforestation of riparian forests.

Environmental factors affect the response of microbial extracellular enzyme activity in soils when determined as a function of water availability and temperature.

Microorganisms govern soil carbon cycling with critical effects at local and global scales. The activity of microbial extracellular enzymes is generally the limiting step for soil organic matter mineralization. Nevertheless, the influence of soil characteristics and climate parameters on microbial extracellular enzyme activity (EEA) performance at different water availabilities and temperatures remains to be detailed. Different soils from the Iberian Peninsula presenting distinctive climatic scenarios were sampled for these analyses. Results showed that microbial EEA in the mesophilic temperature range presents optimal rates under wet conditions (high water availability) while activity at the thermophilic temperature range (60°C) could present maximum EEA rates under dry conditions if the soil is frequently exposed to high temperatures. Optimum water availability conditions for maximum soil microbial EEA were influenced mainly by soil texture. Soil properties and climatic parameters are major environmental components ruling soil water availability and temperature which were decisive factors regulating soil microbial EEA. This study contributes decisively to the understanding of environmental factors on the microbial EEA in soils, specifically on the decisive influence of water availability and temperature on EEA. Unlike previous belief, optimum EEA in high temperature exposed soil upper layers can occur at low water availability (i.e., dryness) and high temperatures. This study shows the potential for a significant response by soil microbial EEA under conditions of high temperature and dryness due to a progressive environmental warming which will influence organic carbon decomposition at local and global scenarios.

Influence of soil characteristics and leaching rate on copper migration: column test

Soil copper (Cu) supply is used to correct Cu deficiency in many crops grown in southern Mediterranean areas. Oversupply of this fertilizer may contaminate soil and groundwater. This study aims to assess Cu migration in different soils of Moroccan agricultural areas. Three soil samples were collected from different areas. For each soil, three annual leaching rates were tested: 35 mm, 237 mm, and 565 mm for a sandy soil; 35 mm, 70 mm, and 140 mm for a clay calcareous soil; and 35 mm, 103 mm, and 247 mm for silty clay soil. The leaching experiments were conducted in columns filled identically up to 30 cm with each soil sample. Then, 0.6 mg of Cu kg−1 was added to the soil surface in the sulfate form (CuSO4.5H2O). The results showed that soil Cu loss increased mainly with leaching rate: y = 0.004 x – 0.10 (R2 = 0.97) where y: soil Cu loss (10−4 meq 100 g−1) and x: leaching rate (mm). The regression analysis did not reveal a significant influence of the soil properties on Cu leaching. However, the Cu loss seems insignificant regarding the no recurrence of high annual leaching rate (over 500 mm), in south Mediterranean areas. Also, soil Cu accumulation risk occurred in all studied soils. For sandy soil, available Cu content was 78% higher in the top layer (0–10 cm) than its content in the middle (10–20 cm) and lower (20–30 cm) layers. Furthermore, a release of bioavailable Cu was recorded in silty clay and clay calcareous soils at a leaching rate of over 70 mm.