Short-term Flooding Research Articles

Real-time Flood Prediction using a Big Data Approach

Floods have historically presented serious threats, putting infrastructure and lives in jeopardy throughout the world. There has never been a greater need for accurate and fast flood forecasts as climate change exacerbates existing situations. By using state-of-the-art algorithms and real-time integration to create a groundbreaking flood prediction platform, this research seeks to close important gaps. A comprehensive resource is created by combining a variety of datasets, including Internet of Things sensor streams, hydrological readings, and meteorological observations. For extremely accurate short-term flooding forecasts, advanced machine learning techniques—like deep neural networks and hybrid statistical methods—are trained on the live dataset. Pre-warnings from the suggested adaptive system are expected to become more and more dependable, enhancing readiness and reaction operations. Going forward, continually refining models with growing data repositories, exploring novel inputs, and extending the framework to other natural hazards will further strengthen resilience against these escalating threats.

Flooding Length Mediates Fencing and Grazing Effects on Soil Respiration in Meadow Steppe.

Grassland management affects soil respiration (Rs, consists of heterotrophic respiration and autotrophic respiration) through soil micro-ecological processes, such as hydrothermal, plant root, organic carbon decomposition and microbial activity. Flooding, an irregular phenomenon in grasslands, may strongly regulate the response of soil respiration and its components to grassland management, but the regulatory mechanism remains unclear. We conducted a 3-year experiment by grassland management (fencing and grazing) and flooding conditions (no flooding (NF), short-term flooding (STF) and long-term flooding (LTF)) to study their effects on Rs and its components in a meadow steppe in the Hui River basin of Hulunbuir. We found differences in the patterns of Rs and its components under grassland management and flooding conditions. In 2021-2023, the temporal trends of Rs, heterotrophic respiration (Rh) and autotrophic respiration (Ra) were generally consistent, with peaks occurring on days 190-220, and the peaks of grazing were higher than that of fencing. In NF, Rs of grazed grassland was significantly higher than that of fenced grassland in 2021-2022 (p < 0.05). In STF and LTF, there was no significant difference in Rs between fenced and grazed grassland (p > 0.05). The dependence of Rs on soil temperature (ST) decreased with increasing flooding duration, and the dependence of Rs on ST of grazed grassland was higher than fenced grassland under NF and STF, but there was no difference between fenced grassland and grazed grassland under LTF. In addition, Rh was more sensitive to ST than Ra. This may be due to the different pathways of ST effects on Rs under grazing in different flooding conditions. Our study indicates that the effect of flooding on Rs is the key to the rational use of grassland under future climate change. To reduce regional carbon emissions, we recommend grazing on flooding grassland and fencing on no-flooding grassland.

Flood Tolerance of Hybrid Napier (Pennisetum purpureum x Pennisetum glaucum) Cultivars

A pot culture study was conducted from February to May 2020 at the Agronomy Farm, Department of Agronomy, College of Agriculture, Vellanikkara, Kerala to study the effects of short-term flooding on the growth, physiology, and yield of four high-yielding cultivars of hybrid napier (Pennisetum purpureum x Pennisetum glaucum) cultivated in Kerala. The experiment followed a 4 x 2 factorial Completely Randomized Design with three replications. The treatments comprised two factors: varieties and flooding treatments. The four hybrid napier varieties used in the study were CO-3 (V1), CO-5 (V2), IGFRI -3 (V3), and Suguna (V4). The flooding treatments included no flooding (F0) as a control and short-term flooding stress treatment (F1) at three different growth stages: 30 days after planting (DAP), 60 DAP and just after the first harvest (75 DAP). Flooding stress was imposed for seven days by inundating water in the pots up to 3-4 cm above the soil level. Flooding at all three stages resulted in a significant reduction in plant height, tiller number, leaf number and above-ground biomass for all varieties. A severe reduction in growth and yield parameters was observed when flooding stress was imposed immediately after the first harvest. Among the varieties, CO-5 had the tallest plants, followed by Suguna, CO-3, and IGFRI-3. When exposed to flooding stress, variety CO-5 was also found to be significantly superior in terms of above-ground biomass production, followed by CO-3. Superoxide dismutase (SOD) activity increased in all varieties due to flooding stress, with a pronounced increase observed in Suguna. Variety CO-5, which exhibited greater plant height and above-ground biomass production, was found to be more tolerant to flooding stress, while variety IGFRI-3, with a dwarf plant stature and the lowest biomass yield, was identified as sensitive to short-term flooding stress.

Response of soil bacterial populations to application of biosolids under short-term flooding

Biosolids are applied to agricultural land as a soil conditioner and source of crop nutrients. However, there is concern that bacteria from biosolids may become established in soils, particularly if that soil becomes water-logged. This study examined the microbial community of arable soils cultivated with barley under different applications of biosolids (0, 24t/ha, 48t/ha) in laboratory mesocosms which simulated a 10-day flood. Nutrients (P and N) and organic matter in the soil increased with application rate, but plant growth was not affected by biosolid application. The biosolids contained 10× more genetic material than the soil, with much lower bacterial diversity, yet application did not significantly change the taxonomy of the soil microbiome, with minor changes related to increased nutrients and SOM. Anaerobic conditions developed rapidly during flooding, causing shifts in the native soil microbiome. Some bacterial taxa that were highly abundant in biosolids had slightly increased relative abundance in amended soils during the flood. After flooding, soil bacterial populations returned to their pre-flood profiles, implying that the native microbial community is resilient to transient changes. The short-term changes in the microbiome of biosolid-amended soils during flooding do not appear to increase the environmental risk posed by biosolid application.

Differences in physiological and biochemical responses to short-term flooding among the three avocado (Persea americana Mill.) races

Avocado (P. americana Mill.) trees are classified into three botanical races, Mexican (M), Guatemalan (G), and West Indian (WI), each distinguished by their geographical centers of origin. While avocados are considered highly sensitive to flooding stress, comparative responses of the different races to short-term flooding are not known. This study assessed the differences in physiological and biochemical responses among clonal, non-grafted avocado cultivars of each race to short-term (2–3 days) flooding. In two separate experiments, each with different cultivars of each race, container-grown trees were divided into two treatments: 1) flooded and 2) non-flooded. Net CO2 assimilation (A), stomatal conductance (gs), and transpiration (Tr) were measured periodically over time beginning the day before treatments were imposed, through the flooding period, and during a recovery period (after unflooding). At the end of the experiments, concentrations of sugars in leaves, stems, and roots, and reactive oxygen species (ROS), antioxidants, and osmolytes in leaves and roots were determined. Guatemalan trees were more sensitive to short-term flooding than M or WI trees based on decreased A, gs, and Tr and survival of flooded trees. Guatemalan trees generally had less partitioning of sugars, particularly mannoheptulose, to the roots of flooded compared to non-flooded trees. Principal component analysis showed distinct clustering of flooded trees by race based on ROS and antioxidant profiles. Thus, differential partitioning of sugars and ROS and antioxidant responses to flooding among races may explain the greater flooding sensitivity of G trees compared to M and WI trees.

Consequences of sea level rise for high metal(loid) loads in the Ría of Huelva estuary sediments

Ría of Huelva, located in southwestern Spain, is a highly metal(loid)-contaminated estuary system where sediments are exceeding action limits in an increasing order for Cd, Zn, Pb, Cu, and As. With a predicted sea level rise over the next 50 years, the estuary will be subject to flooding with brackish water or seawater. To evaluate the risk of metal(loid) mobilization under future climate scenarios, different locations along the estuary were sampled at different depths. Samples were flooded with river water, brackish water, and seawater under different short- and long-term laboratory setups. Potential metal(loid) mobilization showed that water quality standards for As, Pb, Zn, Ni, Cu, and Cd could be exceeded upon seawater flooding. However, metal(loid) mobilization was not predictable solely based on sediment loads. The driving factors for cation and anion mobility were identified to be mainly pH under low salinity and competitive desorption under high salinity conditions. Further drivers such as wave movement or labile C input in C-limited systems were found to enhance metal(loid) mobilization. Long-term flooding of intact sediment cores revealed that sea level rise will have different effects on the estuary system depending on duration of flooding. Short-term flooding in the near future will first affect alkaline sediments and enhance currently low cation mobilization, while anion mobilization due to reductive Fe dissolution will remain high. Once acidic sediments further inland are flooded with seawater, highest contaminant mobilization can be expected as high salinity will further enhance already high cation mobilization under acidic pH. Long-term flooding with seawater will neutralize the sediment pH and limit cation mobilization compared to acidic pH. However, the contaminant load stored in the estuary is so high that, extrapolating data obtained, mobilization could last for >1000 years, e.g. for As, Pb, and Al.

Leaf acclimation to soil flooding and light availability underlies photosynthetic capacity of Lindera melissifolia, an endangered shrub of bottomland forests in the Mississippi Alluvial Valley, USA.

Lindera melissifolia is an endangered shrub indigenous to the broadleaf forest of the Mississippi Alluvial Valley (MAV). In this region, extant colonies of the species are found in periodically ponded habitats where a diversity of broadleaf trees can form well-developed overstory and sub-canopies-these habitat characteristics suggest that soil flooding and light availability are primary drivers of L. melissifolia ecophysiology. To understand how these two factors affect its photosynthetic capacity, we quantified leaf characteristics and photosynthetic response of plants grown in a large-scaled, field setting of three distinct soil flooding levels (no flood, 0day; short-term flood, 45days; and extended flood, 90days) each containing three distinct light availability levels (high light, 30% shade cloth; intermediate light, 63% shade cloth; and low light, 95% shade cloth). Lindera melissifolia leaves showed marked plasticity to interacting effects of flooding and light with lamina mass per unit area (Lm/a) varying 78% and total nitrogen content per unit area (Na) varying 63% from the maximum. Photosynthetic capacity (A1800-a) ranged 123% increasing linearly with Na from low to high light. Extended flooding decreased the slope of this relationship 99% through a reduction in N availability and metabolic depression of A1800-a relative to Na. However, neither soil flooding nor light imposed an additive limitation on photosynthetic capacity when the other factor was at its most stressful level, and the A1800-a-Na relationship for plants that experienced short-term flooding suggested post-flood acclimation in photosynthetic capacity was approaching the maximal level under respective light environments. Our findings provide evidence for wide plasticity and acclimation potential of L. melissifolia photosynthetic capacity, which supports active habitat management, such as manipulation of stand structure for improved understory light environments, to benefit long-term conservation of the species in the MAV.

Chemical Priming with Brassinosteroids to Mitigate Responses of Avocado (Persea americana) Trees to Flooding Stress

Priming involves the exposure of plants to a mild stress to increase tolerance to a more intense stress in the future. Chemical priming with brassinosteroids reduces the negative effects of flooding on the physiology and survival of some plant species. Avocado trees are very susceptible to flooding, and flooding susceptibility is related to the rootstock, which is often derived from seeds. In this study, the effects of chemical priming with two brassinosteroids, 28-homobrassinolide or 24-epibrassinolide, to improve the tolerance of avocado (Persea americana Mill.) trees to short-term flooding was assessed in two separate experiments with seedling trees of avocado cultivars Monroe (Experiment 1) and Reed (Experiment 2). In each experiment, trees were treated with a soil drench of 28-homobrassinolide, 24-epibrassinolide, or deionized water as a control. Trees in each chemical treatment were divided into two flooding treatments: flooded by submerging potted trees in water to above the soil surface or nonflooded. After the flooding treatments had begun, we measured the leaf gas exchange (net CO2 assimilation (A), stomatal conductance (gs), transpiration (Tr) and water use efficiency (WUE)) and the maximal potential quantum efficiency of photosystem II (the ratio of variable to maximum chlorophyll fluorescence; Fv/Fm) daily during the flooding period as indicators of plant stress. After the trees had been unflooded, leaf gas exchange and Fv/Fm were measured periodically during the recovery period. In both experiments, flooding reduced leaf gas exchange and Fv/Fm of trees in the chemical control and 28-homobrassinolide treatments beginning 2–3 days after flooding began until the end of the experiment. However, there was a negligible effect of flooding on leaf gas exchange or Fv/Fm of trees treated with 24-epibrassinolide. In both experiments, a greater percentage of the flooded plants treated with 24-epibrassinolide survived compared to plants in the two other chemical treatments. The results of this study indicate that pretreatment (priming) with 24-epibrassinolide as a soil drench prior to flooding reduces flooding stress of avocado trees.

Dynamics of Spatiotemporal Variation of Groundwater Arsenic Due to Salt-Leaching Irrigation and Saline-Alkali Land

Determining the link between the evolution of salt-leaching irrigation, saline-alkali land, and groundwater arsenic (As) is essential to prevent groundwater arsenic pollution and implement appropriate soil salinization control projects. The objectives of our study were to explore the spatiotemporal correlation of saline-alkali land and salt-leaching irrigation with groundwater As in the Hetao Plain. Therefore, groundwater As concentrations during Period I (2006–2010) and Period II (2016–2020) were collected by historical data and chemical measurements. Salt-leaching irrigation area and saline-alkali land area in Period I and Period II were extracted through remote sensing data. With the increase of the salt-leaching irrigation area level (SLIAL) and saline-alkali land area level (SALAL), the variation trend in groundwater As concentration slightly fluctuated, with an increase in the SLIAL at the low SALAL, which may be because short-term flooding may not considerably enhance As mobilization. Lower groundwater As concentrations appeared in regions with higher SLIAL and lower SALAL. A larger saline-alkali land area (higher SALAL) increased the groundwater As concentration. The path analysis model confirmed that salt-leaching irrigation may increase groundwater salinity to affect groundwater As levels and to decrease the saline-alkali land area. From Periods I to II, the difference in path analysis results may imply that the decrease in the saline-alkali land area may have influenced As mobilization due to competitive adsorption caused by the increase in total dissolved solids (TDS) in groundwater. Our results provide new insights for the impacts of saline-alkali land and salt-leaching irrigation both on groundwater As concentration and the geochemical processes of As enrichment in arid and semi-arid areas with more serious salinization.

190 Effects of Flooding on Grazed Pastures: Forage Quality, GHG Emissions and C Stocks

Abstract Manure creates hot spots of nutrients concentration, and consequently nutrient losses to air and water. In flood-prone areas these losses represent a major concern for environment. However, there is a gap on the understanding of the effects of recurring, short-term flooding on environmental and forage characteristics. This study evaluated the effects flooding on soil carbon (C) stock; and greenhouse gas (GHG) emissions (methane, CH4; nitrous oxide, N2O; and carbon dioxide, CO2) from soil; and forage dry matter and quality in flooded and non-flooded grazed pastures during four sampling periods (spring, early summer, late summer, and fall) of 2021. Soil samples were collected from 0-100cm, forage samples were cut at stubble height and soil greenhouse gases (GHG) emissions were monitored using the static chamber methodology. Preliminary results show trends of reduced forage digestibility in flooded pastures. No differences were observed on forage dry matter. Overall, there was no differences between CO2 emission from soil in flooded and non-flooded areas. Soil CH4 fluxes were primarily negative, and flooding seems to reduce the sink potential for CH4 from soil, except during early summer. For N2O the effects of season were very pronounced, increased emissions from spring to early summer and throughout fall in both flooded and non-flooded pastures. We did not observe any N2O sinks, and no difference between treatments. Flood-prone pastures had decreased C stock in comparison with non-flood pastures. Preliminary results show that forage production may represent a good option for flooded areas, since no effects were observed on mass and few effects on quality. However, flooding reduced C stock potential and CH4 sinks. A second sampling season will be performed in 2022 to further observe these results and allow for C-equivalent flux calculations. The balance between productivity and environmental impacts of flood-prone pastures will then be assessed.

Extractable Potassium as Affected by Soil Moisture Conditions

ABSTRACT Soil potassium (K) analysis is a widely adopted tool to evaluate exchangeable K content, but variations in soil moisture before sampling, the drying method, and the extractant used could influence the results. Therefore, the objectives of this work were as follows: evaluate the effect of soil drying before testing on extractable K; evaluate the effect of a short-term flooding on soil K availability; and determine the relationships between field-moist and oven dried soil K concentrations extracted with Mehlich-3 and Ammonium Acetate (NH4OAc) methods, with and without recent K application. Five Uruguayan agricultural soils were incubated in pots at different humidity levels, and they were analyzed field moist (FM), air-dried (AD) and oven-dried (OD), using two different extractants: NH4OAc and Mehlich-3. The K concentration from FM sample were higher than from OD for both extractants, except for the soil with the lowest K value and the non-illitic clay mineral, where the results were opposed. The K concentrations from FM of samples with 100% humidity were higher than those of 50%. No significant effect on K availability was detected due to the occurrence of short-term flooding before sampling. NH4OAc extracted more K than Mehlich-3 in all soils and treatments.

Zapažanja poljoprivrednika o utjecaju prekomjerne kiše praćene poplavama na poljoprivredna zemljišta u Hrvatskoj

Extreme events have produced more rain and became more frequent in many regions around the world, and these trends will rise with the warming of the planet. The vulnerable agricultural sectors, directly dependent on the climate, is predicted to be significantly affected by climate change, with an expected decline in future crop yields. We provide data on the effects of floods, because of excessive rain, on the agricultural sector in Croatia, with emphasis on its northern Pannonian region. Data collected for the period 2015-2020 are based on a 34-question survey, conducted among farmers previously reporting on climate-related damages to their crops. With almost 80% of farmers having experienced flooding on their field plots in the last 5 years (mostly short-term flooding, i.e. waterlogging of up to seven days), it is clear that this type of investigation needs further attention. Data suggested that floods most often occurred in the plant germination phase (before the 5th leaf) representing a risk for plant damage and consequent reduction in yields. A combination of mitigation and adaptation measures could minimize water retention in the fields and reduce damage, however, our survey implied that farmers scarcely use such measures. Knowledge gained in this study represents the first step toward understanding potential negative effects of the extreme events on the fragile agricultural sector in Croatia and could help authorities in decision making with the aim to reduce the degree of uncertainty associated with climate change effects.

On the use of orchards to support soil aquifer treatment systems

Soil aquifer treatment (SAT) is a practice used to enhance groundwater storage through intermittent percolation of treated wastewater effluent in designated infiltration basins. Due to proximity to urban regions, land availability for SAT infiltration basins is a limiting factor. Furthermore, with the growing population, SAT systems are faced with an increase in effluent volumes meant for recharge. The present study experimentally explores, for the first time, the feasibility of the short-term flooding of a citrus orchard with secondary effluent, as an alternative for an additional dedicated infiltration area for SAT, namely agricultural soil aquifer treatment (Ag-SAT). Orange trees were planted in two different agricultural setups, on flat soil and atop a ridge. Sporadic intermittent winter flooding experiments, lasting 24 and 48 h, were conducted. Volumetric water content (VWC) and oxidation-reduction conditions were continuously monitored. Concurrently, water samples were collected and analyzed for total organic carbon and nitrogen species, along with leaf health measurements. Results were compared to an adjacent control plot, where no flooding with effluent was applied. Contaminant removal rates under the ridge setup resembled active SAT basins. Moreover, chemical analysis of the water samples and VWC readings demonstrated that higher water quality and faster root zone aeration (following flooding) were obtained under the ridge, which appears to be the better Ag-SAT setup. According to a principal component analysis (PCA), the dissolved oxygen explains 75% of the variability of effluent chemistry under the ridge, illustrating that oxic conditions prevailed in this setup. This study demonstrates that while many other concerns still need to be addressed, using agricultural plots as recharge basins for SAT during the winter appears to be a promising way to supplement recharge basins while having no impact on tree health.

Enhanced topsoil P leaching in a short term flooded calcareous soil with combined straw and ammonium nitrogen incorporation

Straw incorporation (SI) coupled with ammonium nitrogen (AN) application is a management strategy for storing organic carbon (OC) and optimizing vegetable yields in intensively managed calcareous soils of North China. However, during short term flooded conditions, the resulting soil acidification and subsequent Fe reduction processes may affect the transformation of soil Fe/Al-bound phosphorus (Fe/Al-P) and the mobility of phosphate in soil. This study was conducted simulating the condition of short term flooding in order to investigate P leaching and the contents of soil inorganic P fractions, Fe(III) reduction and P adsorption kinetics in calcareous soil with four treatments; control (C), straw powder incorporation (SI), SI with subsequent AN elution (SN) and SI with subsequent sulfuric acid elution (SH). The results showed that the SI treatment promoted the transformation of Ca-bound P (Ca-P) in soil to Fe/Al-P due to acidification but had no effect on P leaching. The SN treatment significantly decreased the topsoil Fe/Al-P content and maximum P sorption capacity through Fe(III) reduction, whereas it increased the total amount of P leached under flooded conditions by 86.8%. In contrast, SH promoted Fe/Al-P accumulation as well as increase the soil maximum P sorption capacity in the topsoil, leading to a decrease in P leachate of 38.1% compared with the SI treatment. The SN treatment was responsible for high P mobility through promotion of Fe(III) reduction and inhibition of acidification processes. Such findings in the present study highlight that 1) SI coupled with AN induced the Fe(III) reduction releasing associated P while 2) SI coupled with acidification significantly inhibited the P leaching, which is of environmental benefit. However, the results presented herein were limited to a single soil type. Future studies should validate the processes found in the present study across other soil types.

Tree‐soil Interactions Through Water Release to a Floodplain Ecosystem: a Case Study of Black Box (Eucalyptus largiflorens) on Loamy Sands

Australia’s Murray-Darling Basin (MDB) is an agriculturally and ecologically valuable region impacted by water abstraction and climate change. Black Box (Eucalyptus largiflorens (Myrtaceae)), an important floodplain tree largely endemic to the Basin is of concern because its overall condition is sub-optimal. Knowledge about key aspects of Black Box tree function such as mineral nutrition remains limited. This field study examined the latter by measuring essential plant nutrients, aluminium, and soil chemistry over 12 months spanning an environmental water release event. Samples were collected 4–8 weekly from mature trees on loamy sands of the Hattah Lakes system in north-western Victoria. This commenced prior to water release, continuing through peak levels at the study sites, to recession. Paired leaf and soil samples were obtained from/beneath mature trees at 8 time-points in 2017–2018. Flooding induced mostly temporary soil chemical changes in the surface horizon, which enhanced trace-nutrient access to trees. Results suggest that the short-term flooding of Black Box on drained loamy sands likely provides nutritional advantage by generating soil chemical fluxes. They also raise questions about flooding-induced movement of nutrients through the soil profile, and about the combined effects of pedology and duration of flooding on the nutritional health of Black Box.

Transition to new technologies of rice cultivation in the Krasnodar Territory

Currently used in Russia traditional technologies of rice cultivation with continuous or short-term flooding of rice paddies are ineffective for a number of factors, the main of which are the high cost and high labor intensity of rice production. Research in the field of rice cultivation has identified four main promising technologies that can reduce the cost of rice produced: 1 - intermittent flooding; 2 - periodic moistening without creating a layer of water; 3 - sprinkling, including surface irrigation; 4 - drip irrigation. The purpose of our research was to develop a new drip irrigation rice cultivation technology adapted for the climatic and soil conditions of the Krasnodar Territory. As a result of the research carried out, a drip irrigation technological scheme was developed and implemented for LLC “Chernoerkovskoye” of the Slavyansky district of the Krasnodar region. The developed scheme of rice cultivation on drip irrigation has proven its effectiveness, expressed in improving the reclamation state of soils, increasing the profitability of production and increasing the yield, reducing the irrigation rate, the cost of rice grain and labor intensity.

English

The present work focused on evaluation of the physiological and metabolic behavior of alfalfa (Medicago sativa L., var. Siriver), when faced with two important ecosystems constraints, namely salinity and flooding-associated hypoxia. After germination, seedlings in symbiosis with Sinorhizobium meliloti were grown on different salt concentrations (0, 20 and 50 mM NaCl). At four weeks post-germination, plants were submitted to a five-day long flooding treatment and then analyzed for various physiological (growth, biomass) and biochemical (proteins, chlorophylls, ions, proline) parameters. Our results showed that when M. sativa was cultured on moderate (20 mM NaCl) or average (50 mM NaCl) salt stress, the classical mechanisms of stress response (ions and proline accumulation) are set up and the growth (FW, DW, growth of aerial parts) was moderately affected by salt. In a situation of average salt stress (50 mM NaCl), the combined salinity and short-term flooding led to an early alteration of the photosynthetic machinery and a modification of ions and proline contents in the leaves. Key words: Chlorophyll, hypoxia, legume, NaCl, proline, salinity.

Transcriptome analysis on responses of orchardgrass (Dactylis glomerata L.) leaves to a short term flooding

BackgroundOrchardgrass (Dactylis glomerata L.) is a popular cool-season perennial grass with a high production value, and orchardgrass seed is the fourth top-selling forage grass seed in the world. However, its yield and quality are often affected by flooding. To date, the molecular responses of orchardgrass to flooding were poorly understood.ResultsHere, we performed mRNA-seq to explore the transcriptomic responses of orchardgrass to a short term flooding (8 h and 24 h). There were 1454 and 565 differentially expressed genes identified in the 8 h and 24 h of flooding, respectively, compared to well control. GO functional enrichment analysis showed that oxidoreductase activity and oxidation-reduction process were highly present, suggesting that flooding induced the response to oxygen stress. Pathways enrichment analysis highlights the importance of glutathione metabolism, peroxidase, glycolysis and plant hormone signal transduction in response to flooding acclimation. Besides, the ROS clearance system is activated by significantly expressed glutathione S-transferase and genes encoding SOD and CAT (CAT1 and CDS2). The significant positive correlation between RNA sequencing data and a qPCR analysis indicated that the identified genes were credible.ConclusionIn the process of orchardgrass response to flooding stress, multiple differential genes and biological processes have participated in its acclimation to flooding, especially the biological processes involved in the removal of ROS. These results provide a basis for further research on the adaptation mechanism of orchardgrass to flood tolerance.

Changes in Yield Components of Paddy Rice Due to Short-Term Flooding at the Panicle Developmental Stage and the Ripening Stage

Changes in Yield Components of Paddy Rice Due to Short-Term Flooding at the Panicle Developmental Stage and the Ripening Stage

Current State and Conditions of Landscape Formation of Ilovlya River Floodplain (Middle Don)

The basis for the study is instrumental terrain profiling using level, geobotanical descriptions, GPR studies, soil sections and manual drilling with a soil sampler. The species composition of vegetation indicates very rare and short-term flooding in high water. Vegetation elements of the low floodplain are marked on the areas directly adjacent to the riverbed at altitudes up to 1.5 m above the inter-level level. Further, along the profile, there are no signs of flooding and standing water. In the soil section there are no iron oxide (II and III) and fading of salts in all horizons up to the depth of 150 sm. The borders between horizons are expressed unclear. This indicates sufficient surface moisture and thus washing of the upper horizons of the soil. The floodplain oak forest is in good condition, there are no dry-top trees. This also indicates that the soil and groundwater are not saline. Studies have shown that the location of the groundwater mirror is close to horizontal, and its level exactly corresponds to the water level in the river. This position of the ground water mirror is typical for river floodplains that occupy an intermediate position between the floodplains of humid and arid zones. The relief of the river floodplain was formed in more water years than observed in the late 20th – early 21st centuries. The first floodplain level (low floodplain) has an excess of no more than 1–1.5 meters above the inter-level of the river. In modern hydrological conditions, only this level is guaranteed to flood every spring.