High Soil Research Articles

Highly alkaline electrokinetic extraction: Characteristics of chromium mobilization, conversion and transport in high alkalinity soil

In site chromium (Cr) contaminated soil characterized by high alkalinity and carbonate content, protons are not effectively targeted for Cr(III) mobilization but rather accelerate the reduction of easily transportable Cr(VI) within the acidification electrokinetic (EK) system. As an alternative, the highly alkaline extraction conditions (HAECs) maintained by anolyte regulation are explored owing to the ability to desorb strong binding Cr(VI) and form anionic Cr(III)-hydroxides (Cr(OH)4−, Cr(OH)52−). The results demonstrate that HAECs were more efficient in mobilizing ions in severe alkalinity and electrical conductivity soil compared to organic acid acidifying extraction conditions (OAECs). Simultaneously, a limited amount of soluble Cr(III) was produced; however, its transportation was hindered and more noticeable in the case of Cr(VI), displaying a distinct retention phase within the intermediate soil chamber. The antagonistic interplay between electromigration and electroosmotic flow was considered the main responsible factor. The conversion intensity of Cr(VI) to Cr(III) was inhibited at HAECs. The promising mobilization and low conversion intensity contributed to total Cr removal. At HAECs, enhanced electromigration and electroosmotic flow combined with a favorable oxidation environment may facilitate in situ delivery of oxidants, offering practical implications for the EK detoxification of high alkalinity site soil contaminated with Cr. The practicability of HAECs is likely to be enhanced when the cost-benefit balance of providing a simultaneous energy supply during site treatment is resolved.

Heterosis for Interactions between Insect Herbivores and 3-Line Hybrid Rice under Low and High Soil Nitrogen Conditions.

Hybrid rice results from crossing a male-sterile line (the A line) with a pollen doner (the restorer or R line). In 3-line hybrid breeding systems, a fertile B line is also required to maintain A line populations. Heterosis is defined as a condition of traits whereby the hybrid exceeds the average of the parental lines. Heterobeltiosis is where the hybrid exceeds both parents. Hybrid rice may display heterosis/heterobeltiosis for growth, yield and resistance to herbivores, among other traits. In a greenhouse experiment, we assessed the frequency of heterosis for resistance to the brown planthopper (Nilaparvata lugans (BPH)), whitebacked planthopper (Sogatella furcifera (WBPH)) and yellow stemborer (Scirpophaga incertulas (YSB)) in eight hybrids under varying soil nitrogen conditions. We also assessed plant biomass losses due to herbivore feeding as an approximation of tolerance (the plant's capacity to compensate for damage). Nitrogen reduced resistance to all three herbivores but was also associated with tolerance to WBPH and YSB based on improved plant survival, growth and/or yields. Plant biomass losses per unit weight of WBPH also declined under high nitrogen conditions for a number of hybrids, and there were several cases of overcompensation in rice for attacks by this herbivore. There was one case of nitrogen-related tolerance to BPH (increased grain yield) for a hybrid line with relatively high resistance, likely due to quantitative traits. Heterosis and heterobeltiosis were not essential to produce relatively high herbivore resistance or tolerance across hybrids.

Metals in coastal groundwater systems under anthropogenic pressure: a synthesis of behavior, drivers, and emerging threats

AbstractSubmarine groundwater discharge (SGD) dynamically links land‐ and ocean‐derived chemical constituents, such as metals, in the coastal ocean. While many metals are sediment‐bound, changing environmental conditions, particularly along the coast, may lead to increased release of metals to their dissolved and more bioavailable form. Here, we review metal behavior, speciation, and drivers of mobilization in the coastal environment under anthropogenic influence. We also model global metal contamination risk to the coastal ocean via SGD considering anthropogenic and hydrogeologic pressures, where tropical regions with high population density, SGD, and acid sulfate soils (4% of the global coast) present the highest risk. Although most SGD studies focus on other analytes, such as nutrients, this review demonstrates the importance of considering SGD as a critical pathway for metals to reach the coastal ocean under rapidly changing environmental conditions.

Soil environmental anomalies dominate the responses of net ecosystem productivity to heatwaves in three Mongolian grasslands

Climate change is causing more frequent and intense heatwaves. Therefore, it is important to understand how heatwaves affect the terrestrial carbon cycle, especially in grasslands, which are especially susceptible to climate extremes. This study assessed the impact of naturally occurring, simultaneous short-term heatwaves on CO2 fluxes in three ecosystems on the Mongolia Plateau: meadow steppe (MDW), typical steppe (TPL), and shrub-grassland (SHB). During three heatwaves, net ecosystem productivity (NEP) was reduced by 86 %, 178 %, and 172 % at MDW, TPL, and SHB, respectively. The changes in ecosystem respiration, gross primary production, evapotranspiration, and water use efficiency were divergent, indicating the mechanisms underlying the observed NEP decreases among the sites. The impact of the heatwave in MDW was mitigated by the high soil water content, which enhanced evapotranspiration and subsequent cooling effects. However, at TPL, insufficient soil water led to combined thermal and drought stress and low resilience. At SHB, the ecosystem's low tolerance to an August heatwave was heavily influenced by species phenology, as it coincided with the key phenological growing phase of plants. The potential key mechanism of divergent NEP response to heatwaves lies in the divergent stability and varying importance of environmental factors, combined with the specific sensitivity of NEP to each factor in ecosystems. Furthermore, our findings suggest that anomalies in soil environment, rather than atmospheric anomalies, are the primary determinants of NEP anomalies during heatwaves. This challenges the conventional understanding of heatwaves as a discrete and ephemeral periods of high air temperatures. Instead, heatwaves should be viewed as chronologically variable, compound, and time-sensitive environmental stressors. The ultimate impact of heatwaves on ecosystems is co-determined by a complex interplay of environmental, biological, and heatwave features.

Global comparison shows that soil bacterial communities in extreme pH soils are more structured by deterministic processes

A major aim of microbial ecology is the search for basic ‘rules’ that dominate variation in microbial communities. An earlier comparison of several soil successional series showed that pH explained variation in the relative importance of stochastic versus deterministic processes in bacterial communities. In neutral pH soils, bacterial communities were more strongly influenced by stochastic processes than in low or high pH soils. Here, we took a broad level approach to attempt a more definitive answer of whether soil pH dominates bacterial community structuring using the global database of 237 samples. The beta-NTI showed that at both a global and continental scale, samples with low pH were dominated by deterministic processes, while in samples at around neutral pH, stochastic processes dominated. At high pH, stochasticity dominated on the global scale, but on several continents, the beta-NTI showed determinism predominating. Overall, it appears that bacterial community structuring is strongly and predictably affected by pH, with the most consistent difference observed between determinism at low pH and stochasticity at neutral pH. There is a need for hypothesis testing to explain why this trend exists. It is possible that at low pH, there is a greater selection for consortia to exploit resources, which leads to more predictable, deterministic combinations of species co-occurring. Additionally, the high energy demands for homeostasis and the constraints from the lack of available nutrient resources may impose greater niche-based competition, resulting in more deterministic community structuring at low pH.

Arsenite tolerance and removal potential of the indigenous halophilic bacterium, Halomonas elongata SEK2.

The indigenous halophilic arsenite-resistant bacterium Halomonas elongata strain SEK2 isolated from the high saline soil of Malek Mohammad hole, Lut Desert, Iran, could tolerate high concentrations of arsenate (As5+) and arsenite (As3+) up to 800 and 40 mM in the SW-10 agar medium, respectively. The isolated strain was able to tolerate considerable concentrations of other toxic heavy metals and oxyanions, including Cadmium (Cd2+), Chromate (Cr6+), lead (Pb2+), and selenite (Se4+), regarding the high salinity of the culture media (with a total salt concentration of 10% (w/v)), the tolerance potential of the isolate SEK2 was unprecedented. The bioremoval potential of the isolate SEK2 was examined through the Silver diethyldithiocarbamate (SDDC) method and demonstrated that the strain SEK2 could remove 60% of arsenite from arsenite-containing growth medium after 48 h of incubation without converting it to arsenate. The arsenite adsorption or uptake by the halophilic bacterium was investigated and substantiated through Fourier-transform infrared spectroscopy (FTIR), Scanning Electron Microscope (SEM), and Energy Dispersive X-ray (EDX) analyses. Furthermore, Transmission electron microscope (TEM) analysis revealed ultra-structural alterations in the presence of arsenite that could be attributed to intracellular accumulation of arsenite by the bacterial cell. Genome sequencing analysis revealed the presence of arsenite resistance as well as other heavy metals/oxyanion resistance genes in the genome of this bacterial strain. Therefore, Halomonas elongata strain SEK2 was identified as an arsenite-resistant halophilic bacterium for the first time that could be used for arsenite bioremediation in saline arsenite-polluted environments.

Vegetation at the former open-pit Ningyo-toge mine, 36 years after closure treatment: Impact of soil cover on woody plant establishment and dominance of the perennial herb Miscanthus sinensis

Soil cover is a prevailing method used at mine sites to ensure the safety of hazardous materials and restore ecological functions when the base materials are unfavorable for plant growth. The former open-pit Ningyo-toge Mine was backfilled with overburden and neutralized smelting residues and covered with soil in 1987. After 36 years, the vegetation remained dominated by the perennial herb Miscanthus sinensis, and woody plant establishment did not progress successfully. This study investigated the factors that inhibited woody plant establishment at the site. The soil profile survey revealed that the soil cover formed Bg horizons (pseudogley soil) with cloudy mottling, representative of poorly drained soil. In the Bg horizon, woody plant roots of Pinus densiflora and Weigela hortensis exhibited growth inhibition. Elemental analysis revealed that in the Bg horizon the roots of P. densiflora and W. hortensis accumulated high Fe concentrations exceeding 10,000 mg/kg DW at critical levels. Our results suggested that woody plant roots in the Bg horizon may have suffered from chronic oxygen deficiency accompanied by excessive Fe stress in the soil cover. Topsoil water content (<50 mm) and microtopographic features were not critical factors disrupting woody plant establishment because some individuals were growing in areas with high soil water content, exceeding 60%. Considering that woody plant roots were developed primarily in the shallow A horizon, A horizon formation by M. sinensis is a key step in initiating woody plant establishment by improving the soil structure and physiochemical characteristics of the soil cover, such as carbon content, exchangeable nutrients, and air-filled porosity. For successful mine pollution control and vegetation recovery, implementing an appropriate topsoil system, such as native forest soil, loosely graded and minor infiltration layer above the overburden would be necessary.

Influence of Lake Breezes on the Triggering of Moist Convection on the Tibetan Plateau: A Large-Eddy Simulation Study

Abstract Applying 1D surface heterogeneity and observed atmospheric vertical profiles as initial conditions, two sets of large-eddy simulation experiments provided insight into the influence of lake size and soil moisture (SM) on the development of lake breezes and moist convection over land beside the lake. When the lake diameter increased from 20 km to 50 and 70 km, the maximum precipitation increased by 71.4% and 1.29 times, respectively. There are two reasons for larger precipitation over land in large-lake simulations: 1) Stronger and broader updrafts were found near the lake-breeze front (LBF); 2) the air at 2–4 km was moister, probably because more water vapor below 2 km was advected by the lake breezes and transported upward through turbulent exchange. Moreover, when the lake diameter increased from 20 km to more than 50 km, the deep moist convection (DMC) occurred 20 min earlier. This may be related to broader shallow convective cloud and larger vertical velocity of cloud-initiating parcels in large-lake simulations. Shallow moist convection transitioned to DMC earlier with broader clouds under moderate and high soil moisture conditions. Notably, stronger and broader updrafts near the LBFs, along with the advection of moisture induced by the lake breezes, caused the shallow moist convection to reach its peak 1 h earlier in the driest soil moisture case. However, smaller evapotranspiration could not provide sufficient moisture for the development of DMC. Our simulation results show that lake-breeze circulations are essential for the development of moist convections in the lake region.

Aridity threshold for alpine soil nitrogen isotope signature and ecosystem nitrogen cycling.

Determination of tipping points in nitrogen (N) isotope (δ15N) natural abundance, especially soil δ15N, with increasing aridity, is critical for estimating N-cycling dynamics and N limitation in terrestrial ecosystems. However, whether there are linear or nonlinear responses of soil δ15N to increases in aridity and if these responses correspond well with soil N cycling remains largely unknown. In this study, we investigated soil δ15N and soil N-cycling characteristics in both topsoil and subsoil layers along a drought gradient across a 3000-km transect of drylands on the Qinghai-Tibetan Plateau. We found that the effect of increasing aridity on soil δ15N values shifted from negative to positive with thresholds at aridity index (AI) = 0.27 and 0.29 for the topsoil and subsoil, respectively, although soil N pools and N transformation rates linearly decreased with increasing aridity in both soil layers. Furthermore, we identified markedly different correlations between soil δ15N and soil N-cycling traits above and below the AI thresholds (0.27 and 0.29 for topsoil and subsoil, respectively). Specifically, in wetter regions, soil δ15N positively correlated with most soil N-cycling traits, suggesting that high soil δ15N may result from the "openness" of soil N cycling. Conversely, in drier regions, soil δ15N showed insignificant relationships with soil N-cycling traits and correlated well with factors, such as soil-available phosphorus and foliage δ15N, demonstrating that pathways other than typical soil N cycling may dominate soil δ15N under drier conditions. Overall, these results highlight that different ecosystem N-cycling processes may drive soil δ15N along the aridity gradient, broadening our understanding of N cycling as indicated by soil δ15N under changing drought regimes. The aridity threshold of soil δ15N should be considered in terrestrial N-cycling models when incorporating 15N isotope signals to predict N cycling and availability under climatic dryness.

Effect of soil nutrient management on soil weed seed bank dynamics across a soil fertility gradient in smallholder farms, Eastern Zimbabwe

Weed seed banks are latent biotic stress contributors to low crop production among smallholder farms. The objective of this study was to investigate effect of repeated soil nutrient amendments on weed seed bank dynamics in eastern Zimbabwe. Soil samples were taken from three farms with low, medium and high soil organic carbon (SOC) along the catena. Sampled treatments included varying combinations of compound D (7%N, 14%P, 7% K) fertiliser, cattle manure and lime. Weeds that emerged per plot were counted by species and data was tested for normality before running a linear mixed-effects model and Restricted Maximum Likelihood. Principal Component Analysis (PCA) was performed to establish the relationship between seasons, SOC, soil nutrient amendment, and emerged weeds. Significant (p &amp;lt; .05) species richness (Margalef index), and Shannon Weiner index were recorded in the medium (6.4g kg-1soil), high (8 g kg-1 soil) and low (&amp;lt; 3.9 g kg-1soil) SOC. Weed species emergence was significantly (p &amp;lt; .05) influenced by the level of SOC along the catena positions, representing results from the source. Emergency and abundance of weeds such as Richardia scabra, was associated with low SOC acidic sandy soils from the upper catena. However, application of nutrients (NPK+lime treatment) reduced weed species counts from 1.96±0.12 to 1.4±0.12. Cattle manure and NPK+CM treatments recorded significantly higher weed emergence, and weed biomass; compared to the control. Clearly, cattle manure treatments significantly increase the soil weed seed bank; thus, weeding intensity is likely to increase in cattle manure treated fields.

Field tests of square and double exponential pulses for transient resistivity measurements using Wenner arrays and hemispheres

Models of frequency-dependent soil resistivity ρ(f) suggest the dual concept of time-dependent resistivity ρ(t) that, for high resistivity soil, increases from 100 ns to 100 μs, a range of time relevant for lightning backflashover performance calculations. Measurements of ρ(t) can be made by impressing impulse or step current and monitoring voltage rise. Time-dependent resistivity can be established with Wenner or Schlumberger probe arrays and also with oblique fall-of-potential measurements from buried hemispheres. Tests show that rectangular and double-exponential pulse currents both have value. Specialized evaluation using “Drained Net Charge” concepts may yield estimates of low-frequency resistivity ρo.

Phenotype, Biomass, Carbon and Nitrogen Assimilation, and Antioxidant Response of Rapeseed under Salt Stress.

Salt stress is one of the major adverse factors affecting plant growth and crop production. Rapeseed is an important oil crop, providing high-quality edible oil for human consumption. This experiment was conducted to investigate the effects of salt stress on the phenotypic traits and physiological processes of rapeseed. The soil salinity was manipulated by setting three different levels: 0 g NaCl kg-1 soil (referred to as S0), 1.5 g NaCl kg-1 soil (referred to as S1), and 3.0 g NaCl kg-1 soil (referred to as S2). In general, the results indicated that the plant height, leaf area, and root neck diameter decreased with an increase in soil salinity. In addition, the biomass of various organs at all growth stages decreased as soil salinity increased from S0 to S2. The increasing soil salinity improved the distribution of biomass in the root and leaf at the seedling and flowering stages, indicating that rapeseed plants subjected to salt stress during the vegetative stage are capable of adapting their growth pattern to sustain their capacity for nutrient and water uptake, as well as leaf photosynthesis. However, as the soil salinity increased, there was a decrease in the distribution of biomass in the pod and seed at the maturity stage, while an increase was observed in the root and stem, suggesting that salt stress inhibited carbohydrate transport into reproductive organs. Moreover, the C and N accumulation at the flowering and maturity stages exhibited a reduction in direct correlation with the increase in soil salinity. High soil salinity resulted in a reduction in the C/N, indicating that salt stress exerted a greater adverse effect on C assimilation compared to N assimilation, leading to an increase in seed protein content and a decrease in oil content. Furthermore, as soil salinity increased from S0 to S2, the activity of superoxide dismutase (SOD) and catalase (CAT) and the content of soluble protein and sugar increased by 58.39%, 33.38%, 15.57%, and 13.88% at the seedling stage, and 38.69%, 22.85%, 12.04%, and 8.26% at the flowering stage, respectively. In summary, this study revealed that salt stress inhibited C and N assimilation, leading to a suppressed phenotype and biomass accumulation. The imbalanced C and N assimilation under salt stress contributed to the alterations in the seed oil and protein content. Rapeseed had a certain degree of salt tolerance by improving antioxidants and osmolytes.

Effects of soil bulk density on respiratory metabolism and medicinal quality of Rehmannia Glutinosa root

As one of the famous "four huai medicines", Rehmannia glutinosa has a longstanding usage history. This study aimed to determine how variations in soil bulk density impact the respiration metabolism of R. glutinosa root tubers and, consequently, the quality of its medicinal components. We evaluated the enzymatic activities and key metabolic compounds of R. glutinosa across a range of soil bulk densities, which included: pyruvate kinase (PK), pyruvate decarboxylase (PDC), alcohol dehydrogenase (ADH), lactate dehydrogenase (LDH), isocitrate dehydrogenase (IDH), succinate dehydrogenase (SDH), malate dehydrogenase (MDH), and the content of pyruvate, ethanol, lactic acid, succinic acid, malic acid, and quality indicators. High soil bulk density increased the activities of PK, PDC, ADH, and LDH, while decreasing SDH, MDH, and IDH in the roots. This shift in enzymatic activities corresponded to elevated levels of ethanol and lactic acid, and lowered levels of succinic and malic acids. In the additionally, the growth and development of aboveground parts of R. glutinosa were seriously hindered under high bulk weight treatment, and the number of root tubers decreased, root coarser and root length shortened, and the contents of catalpa alcohol and mullein were significantly reduced. Our findings suggest an optimal soil bulk density for R. glutinosa growth to be between 1.2 g/cm3 and 1.4 g/cm3. Based on changes in respiratory metabolism and medicinal quality indicators of R. glutinosa under different soil bulk densities, our findings suggest the optimal soil bulk density for R. glutinosa growth is 1.2 g/cm3 to 1.4 g/cm3. Excessively high soil bulk density will affect the growth and quality formation of R. glutinosa by influencing its metabolism. Recognizing this optimal range is crucial for maximizing the medicinal quality of R. glutinosa, offering valuable insights for cultivation practices.

Assessing and segmenting salt-affected soils using in-situ EC measurements, remote sensing, and a modified deep learning MU-NET convolutional neural network

A study revealed that the Siwa Oasis faces high soil salinity, which negatively impacts agricultural areas and crop productivity, despite its significant economic and agricultural importance. The current research proposes an approach to detect and segment salinity and vegetation areas at Siwa Oasis, Egypt, by combining remote sensing and building a deep learning neural network model-based U-NET algorithm to detect salinity change areas, anticipate further degradation, and predict soil quality indicators. To locate changes among the available images, standard image improvement, classification, and change detection methods have been used. We applied a deep learning modified U-Net (MU-NET) algorithm to segment and produce salinity maps. The MU-NET architecture is a two-level nested U-structure merged with a residual U-block (RUb), which consists of an encoder and a decoder. We applied RUb, which consists of several layers and skip connections. Different combinations of the salinity and vegetation indices were added to the original image to improve segmentation precision. The model was validated and trained using actual data samples collected over a 10-year period from the Landsat 8 satellite, which can monitor and analyse present land cover changes. The dataset consisted of 91 OLI and TIRS spectral images. Each one consists of eleven bands with a spatial resolution of 30 m for bands 1 to 7 and 9. A field survey was used as the main source of data for comparing the proposed model's outputs to assess the error rate. The study region is experiencing an increase in soil salinity in all directions, particularly with regard to the spatial distribution of saline soils, not just the quantitative increase in salt-affected soils. These findings supported the acceleration of soil salinization and vegetation death. The proposed model achieved the highest performance results among the other models and literature and was based on applying method 12 using 13 image layers, with the highest accuracies of 91.27% and 90.83% for salinity and vegetation, respectively.

Почвенная микофлора агроценозов яровых рапса и рыжика

The main aim of agricultural production is development of technologies saving yield. The basic factor in this area is a high effective soil fertility, which depends on soil micromycets. The purpose of the research was to study impact of spring rapeseed and false flax on qualitative and quantitative composition of soil micromycetes in crops agrocenoses in the Krasnodar region. The research was conducted at the V.S. Pustovoit All-Russian Research Institute of Oil Crops in 2020–2022. The objects of the research were soil micromycetes in agrocenoses of spring rapeseed and false flax. There was studied soil layer from 0 to 10 cm as it contains the most side roots of these crops. The soilsuspension of second dilution (1 : 100) was sowed on a Chapek’s nutrient media. The different amounts of fungi Trichoderma spp., Fusarium spp., Penicillium spp., Aspergillus spp., and Mucor spp. were allocated in soil samples. In this complex, number of Trichoderma spp. and Fusarium spp. fungi were higher, at the beginning of the crop vegetation their amounts were in average 5.0–5.6 × 103 and 3.9– 4.4 × 103 CFU/g, respectively. In a phase of yellow pod, the number of fungi-suppressors Trichoderma spp. in soil increased: under rapeseed to 8.0 × 103 CFU/g, under false flax – to 1.1 × 104 CFU/g. The amount of Fusarium spp. fungi in soil at the end of a growing season also raised insignificantly (to 5.5 and 6.2 × 103 CFU/g, respectively). Thus, the quantity of fungi-suppressors Trichoderma spp. in soil under studied oil cole crops increased during a growing season to 8.0 × 103–1.1 × 104 CFU/g that increased the effective soil fertility. It allows recommending them to include into crop rotation with other agricultural crops, which do not have universal diseases with cole crops.

Variety of active ingredients in leaves and flowers of &lt;i&gt;Chamaenerion angustifolium&lt;/i&gt; (L.) Scop., depending on type of natural population

Relevance. Nowadays the popularity of Chamaenerion angustifolium as a medicinal plant and as a tea is growing noticeably. Fireweed is an eclogically plastic species, that does not require high soil fertility and is widespread in Russia. Medical and food industries use leafs as a row material of fireweed. Series of phytochemical studies of Chamaenerion raw material have shown that it contains a wide variety of pharmacologically significant compounds, that accumulate as a result of both primary and secondary metabolism. The most important groups, formed as a result of secondary metabolism, are polyphenols, including flavonoids, phenolic acids and ellagitannins (including enothein B). Concentration of these chemical compounds equals 15% and even hither of the raw material (leaf).The aim. Identification of variability and relationships between the content of various groups of phenolic compounds in raw material of Chamaenerion angustifolium, depending on ecological conditions.Methods. At the first stage of our work was used the cartographic method. Were studied specimens from 27 points, growing in ecologically different areas of the Moscow, Kaluga and Yaroslavl regions. Phenolic compounds were determined using a spectrophotometer: flavonoids in terms of rutin, tannins and the amount of phenolic compounds, using the Folin-Ciocalteu reagent in terms of gallic acid.Results. The content of polyphenols, tannins and flavonoids in raw material of fireweed, collected in different ecological and soil aspects, was measured. Measurement results were compared, using correlation analysis. As the result of content analysis, it was found that the content of polyphenols in the leaves ranged from 9 to 11%, the content of flavonoids fell within the chain range of 2.5-3.5%, tannin content – 5.0-6.5%. A close correlation was found between the content of phenolic compounds and tannins (R=0.972). It indicates, that the shikimate pathway is the main process of biosynthesis secondary metabolites in the Chamaenerion angustifolium plant. Also it means the leading role of local ecological conditions of the studied areas.

Agrivoltaics in Germany - Status Quo and Future Developments

Ground-mounted photovoltaic facilities in open spaces have been common in Germany for many years. However, according to the legislation, these are only supported by the government on poorer quality soils, former military training areas, or along traffic routes. Nevertheless, also on high quality soils it is not forbidden to install ground-mounted photovoltaic facilities. In recent years, Germany has started implementing agrivoltaics, which is an alternative land use concept that combines agriculture and renewable energy production. This opens the possibility to use land of higher soil quality for energy generation without necessarily creating land-use conflicts and being subsidized by the government. This study aims to provide a comprehensive overview of existing and planned agrivoltaic facilities in Germany analyzing them based on various parameters. The data for this study was collected through a community questionnaire and supplemented with data from state institutions. The results indicate that as of March 2023, 21 agrivoltaic facilities with a total capacity of 81.67 MWp have been installed. A strong increase of the installed capacity is expected in 2023 and 2024, reaching approximately 382.59 MWP by the end of 2024. The market development of agrivoltaics is mainly driven by changes in the legal environment which present opportunities for further market ramp-up of agrivoltaics. The adoption of agrivoltaics shows a notable spatial diversity in Germany which appears to be influenced by the interaction between regulatory environments and agricultural structures.

Yield of yellow cooking onions is not affected by added phosphorous fertilizer in muck soils with high soil test phosphorus in Ontario

Excess phosphorus (P) loading has been identified as an important cause of poor water quality in Lake Simcoe. A small (~ 4%) but important source of P is the marshland that was developed for agriculture in and near the Holland Marsh. Applying the optimum rate of P fertilizer is an economical and environmentally friendly approach to crop management. In Ontario, P fertilizer recommendations are made based on the Olsen P soil test that is accredited by the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA). The current study was a response to concern about high application rates of P fertilizer and grower and industry suggestions that the recommended rates for P were too low. The marketable yield of yellow cooking onions was assessed in relation to different rates of P fertilizer in high organic matter (muck) soils. Organic matter ranged from 38- 86%. Small (6 site-years) and large-scale (21 site-years) field trials were conducted in the Holland Marsh area from 2009 to 2011 on muck soils that varied in pre-plant P (17 - 312 mg L-1). The study demonstrated that there was more plant-available P in the soil than was required for optimum yield in most fields, thus P fertilizer applications had no effect on marketable yield of the onions. These results supported the OMAFRA P recommendations for onion production on muck soils, especially for soil test P levels over 61 mg L-1 where a response to applied P is rated as ‘low, rare or no response’.

Exploring the impact of copper excess on soybean genotypes: insights from root morphology and plant ionome

ABSTRACT Global growing demand for food production and commodity increased prices stimulate soybean cultivation in Brazil even in areas with high soil copper (Cu) concentration. This can promote root injuries and nutritional imbalances, reducing the growth and yield of Cu-sensitive soybean genotypes. The study aimed to investigate soybean genotypes potentially adapted to Cu-contaminated zones. Four soybean genotypes (NA 5909, DM 5958, M 6410, and DM 6563) and three Cu concentrations in the nutrient solution (0.03, 1.2, and 2.4 mg L−1) were evaluated. Root and shoot dry mass, root morphology, and inorganic composition of plant tissues were determined. The shoot and root dry mass was affected by Cu excess, especially in DM 5958 genotype, which decreased by up to 46%. Otherwise, the DM 6563 genotype stood out for growing satisfactorily under Cu excess and keeping significant amounts of Cu in the belowground biomass. The Cu excess promoted root thickening and shortening, and altered the ionome of soybean plants by decreasing the concentrations of K, Ca, Mg, and Fe, yet increasing P and N, which caused decreased plant growth. Finally, our outcomes indicated DM 6563 genotype exhibits promising traits for Cu phytostabilization, making it preferable for cultivation in Cu-contaminated areas.

Vigna marina as a Potential Leguminous Cover Crop for High Salinity Soils

The beach bean (Vigna marina) exhibits robust growth in habitats characterised by sandy substrates, limited nutrient availability, and elevated saline levels. The utilisation of V. marina, a potentially beneficial leguminous cover crop, allows for its cultivation in regions characterised by soil salinity, hence facilitating the alleviation of environmental stress and the promotion of nitrogen fixation within the soil. A study assessed the feasibility of V. marina as a leguminous cover crop, in which this legume was cultivated in both coastal and inland soils. Pueraria javanica and Mucuna bracteata, widely recognised as established leguminous cover crops, were used as the control in this experiment. The observations involved were total plant biomass, nitrogenase activity, and leaf chlorophyll content of the host plants. The experiment consisted of five replicates arranged in a randomised complete block design, respectively. The effects of commercialised rhizobial compost on the development of the leguminous plants planted in both plots were also investigated. The results indicated that V. marina flourished in coastal and inland soils with the highest leaf chlorophyll concentration throughout the eight weeks of growth. It showed that V. marina has the potential to outperform the other two established leguminous cover crops when planted in highly salinised soils. The results also showed evidence that V. marina was an excellent potential leguminous cover crop, especially for any agricultural plots of high salinity soils, compared to the other two well-established leguminous cover crops, P. javanica and M. bracteata.