Water Regime Research Articles

Seed Priming with PEG 6000 and Silicic Acid Enhances Drought Tolerance in Cowpea by Modulating Physiological Responses

Cowpea is a nutritionally and economically valuable legume, known for its adaptability to adverse conditions. However, water stress negatively affects its development, requiring technologies to enhance resilience. This study aimed to induce tolerance to water deficit in cowpea through seed priming with polyethylene glycol 6000 (PEG 6000) and silicic acid. A completely randomized experiment was conducted in a phytotron chamber with two water regimes (W50 and W100) and six seed priming treatments, with four replications. Priming consisted of three water potentials induced by PEG 6000 (0 MPa, −0.4 MPa, and −0.8 MPa) and two silicon concentrations (0 and 200 mg L−1). Gas exchange parameters, including photosynthetic rate (A), transpiration rate (E), stomatal conductance (gs), intercellular CO2 concentration (Ci), instantaneous water use efficiency (WUEi), and instantaneous carboxylation efficiency (iCE), were evaluated. Seed priming with PEG 6000 and silicon improved A, WUEi, and iCE under water deficit. Treatments 2 (0 MPa + 200 mg L−1 Si), 3 (−0.4 MPa + 0 mg L−1 Si), and 4 (−0.4 MPa + 200 mg L−1 Si) enhanced gas exchange, suggesting an effective strategy for improving drought tolerance in cowpea and ensuring food security.

Plant species as ecological engineers of microtopography in a temperate sedge-grass marsh

In many temperate marshes, the surface microtopography is determined by specific growth forms of dominant wetland plants. The formation of long-lasting distinct tussocks by some Carex species represents a growth adaptation, which significantly changes the ecosystem and facilitates the survival of other wetland plants. Therefore, the gradual decline of such an ecosystem engineer may affect both species diversity and the surface microtopography of wetlands in the long term. Using in situ terrestrial laser scanning, we analyzed tussock characteristics in five different stands typical of a temperate sedge-grass marsh to determine potential microtopography changes due to an altered water regime. Tussocks of Carex acuta were different in 2D area, perimeter, height, and roundness. The distances among tussocks were similar and distributed evenly in all vegetation stands. The highest tussocks occurred in stands dominated by Carex acuta and in Carex acuta and Calamagrostis canescens mixture stands. Glyceria maxima and Acorus calamus significantly modified the height and the shape of tussocks in contrast to Calamagrostis canescens, which affects tussocks at least and uses them as habitats. The characteristics of tussocks in mixed stands were influenced by the growth characteristics of all co-occurring dominant plants (ecosystem engineers). Frequent shallow short-term flooding is necessary to maintain the current microtopography in the studied sedge-grass marsh as it promotes the dominance of tussock forming wetland plants and excludes ruderal or invasive terrestrial plant species.

Selection of alfalfa water and nitrogen management regimes based on the DSSAT model

Forage crop production globally faces challenges of low water and nitrogen use efficiency alongside increased environmental pressures, particularly in arid and semi-arid regions. The Hetao Irrigation District, a representative area of such regions, is characterized by limited rainfall, high evaporation, insufficient water, and severe soil salinization, which significantly hinder agricultural development. The findings from this study not only address local challenges but also provide insights applicable to other regions facing similar climatic and environmental constraints. This study aimed to optimize water and nitrogen management strategies for alfalfa production in the Hetao Irrigation District by calibrating and validating the DSSAT-FORAGES-Alfalfa model using field experimental data collected during 2022–2023. The calibration involved adjusting key parameters to minimize discrepancies between simulated and observed values, and validation was performed using an independent dataset, evaluated based on metrics such as MAE, RMSE, and R2. The novelty of this research lies in its comprehensive calibration and validation process, which provides a robust framework for simulating alfalfa growth under diverse management scenarios. Various management scenarios were simulated, including six nitrogen application rates (0, 50, 100, 150, 200, and 250 kg ha−1) and seven irrigation levels (45, 55, 65, 75, 85, 95, and 105 mm), to comprehensively evaluate their impacts on alfalfa yield and quality. These scenarios were designed to cover a wide range of practices, from deficit to excessive irrigation and fertilization, providing a robust assessment of optimal management strategies. Results indicated high predictive accuracy, with all performance metrics (e.g., MAE, RMSE, and R2) demonstrating the model’s reliability in simulating alfalfa growth under varying management conditions. Specifically, the normalized RMSE was below 10%, and the coefficient of determination (R2) exceeded 0.9, confirming the model’s robustness. Optimal management involving 260–340 mm of irrigation and 100–150 kg ha−1 nitrogen application over the full growth cycle not only maximizes water use efficiency, but also achieves over 9% water saving and more than 25% reduction in nitrogen fertilizer application, compared to traditional local practices. These findings demonstrate the potential of optimized management strategies to significantly reduce ecological pressures while maintaining high crop productivity.

Asessment of elite Indian wheat genotypes for drought tolerance

To understand the plasticity of adaptation to different environmental conditions, eighteen elite wheat genotypes were evaluated for two seasons (2017-18 and 2018-19) under water-stress and controlled environments at ICAR-Indian Agricultural Research Institute (IARI), Regional station, Indore, India. Combined analysis of variance for grain yield under both water regimes showed that effects due to the water regimes, environment and genotype all interactions were found to be significant. Genotypes viz., NI 5439, HI 8791and HI 1531 were found to perform stable under both water regimes with high mean yield. Based on PCA biplot and GGE biplot analysis it is evident that genotypes HI 8793, HI 8790 and HI 1619 were the highly adapted, most stable and high yielding genotypes. HI 8791, HI 1531, NI 5439, HI 8793, HI 8790 and HI 1619 were identified to be stable for grain yield and can be utilized further in the breeding program for climate resilient wheat varieties development. Keywords: Wheat, Drought, GGE biplot, PCA, yield

Biochar as a drought mitigation tool to enhance growth and water retention in <em>Pinus caribaea</em> M. seedlings

Drought stress significantly challenges tree growth, especially in tropical forestry systems. This study investigates the effect of biochar amendments and different watering regimes on the physiological responses of Pinus caribaea seedlings to drought stress. The experiment was conducted in a controlled nursery environment using three biochar concentrations (0%, 3%, and 6%) and three watering intervals (100 mL every 24, 48, and 96 hours). A total of 300 seedlings were monitored for growth parameters, including height and diameter. Analysis of variance (ANOVA) and principal component analysis (PCA) were used to assess treatment effects. Results demonstrated that higher biochar levels significantly improved growth metrics and water retention. The 6% biochar treatment yielded the greatest increases both in diameter and height, with enhanced water retention attributed to biochar’s ability to improve soil structure and nutrient retention. Moreover, frequent watering in combination with biochar amendments further boosted seedling growth. PCA revealed negative correlations between drought intensity and growth, while biochar treatments correlated positively with improved growth. The findings suggest that biochar amendments can effectively mitigate drought stress in Pinus caribaea seedlings, promoting improved growth and water conservation.

Assessment Of The Kolyma River Hydrological Regime Dynamics In The 21st Century Based On Runoff Formation Model

Using the physically-based model of runoff formation ECOMAG (ECOlogical Model for Applied Geophysics), the response of the Kolyma River’s water regime to ongoing and projected climate changes has been investigated. To operate the ECOMAG model, which calculates daily water discharges for control sections, information was gathered on the characteristics of the land surface and watershed relief, as well as archives of daily observations from meteorological stations within the basin. The calibration and validation of the model, performed for two sections on the Kolyma River and two sections on its tributaries – the Bolshoy Anyuy and Yasachnaya rivers – demonstrated strong agreement between the modelled and observed water discharges for the Kolyma River. Moreover, the analysis of observed water discharges and those calculated by the ECOMAG model reveals similar changes in the water regime that occurred from 1979 to 2020, such as an increase in annual and summer-autumn runoff, and a decrease in the duration of the winter low-flow period. To assess potential changes in the Kolyma River’s runoff in the 21st century, numerical experiments were conducted using the ECOMAG hydrological model and an ensemble of four global climate models. Calculations were performed for the periods 2020–2039, 2040–2059, 2060–2079, and 2080–2099 for four different Representative Concentration Pathway (RCP) scenarios. Anomalies in annual runoff, peak water discharges, flood volumes, winter low-flow periods, and summer-autumn periods were considered. Under all scenarios, the calculations indicate an increase in the annual and summer-autumn runoff of the Kolyma River.

Land Use & Land Cover Dynamics in Kargil Town, Ladakh, India: A Geospatial Analysis Using Remote Sensing & GIS

Understanding land use and land cover (LULC) changes is critical for effective resource management, ecosystem protection, sustainable development, land use and urban planning. LULC maintains a dynamic interface between human activities and natural processes, always changing due to anthropogenic and environmental factors. Monitoring and analyzing these changes over time can be efficiently done using remote sensing and GIS techniques. This research is aimed to analyse LULC changes from 1990 to 2022 in Kargil Town situated in the arid and rugged region of the Union Territory of Ladakh. Multi-temporal satellite imagery from LANDSAT 4-5 TM, LANDSAT-7 ETM+, and LANDSAT-8,9 OLI has been used to prepare LULC maps covering the years 1990, 2000, 2010, and 2022, using different GIS software like ArcGIS Pro, ERADAS Imagine, and Google Earth Pro, showing substantial alteration in land cover classification over the period. Rule-based maximum likelihood classification (MLC) algorithm was utilized in the present study. The results shows a remarkable increase in built-up areas, with a proportionate rise of around 326.90% throughout this period of study, which corresponds to an observable spread of urbanization owing to population increase, development of infrastructure, immigration and tourist influx. In contrast, agricultural land has been decrease by -27.62%, indicating a conversion from traditional farming to urbanization and commercial activities; vegetation cover in the area diminished by -10.50% primarily due to encroachment for urban development and deforestation. Barren land, the dominant category, decreased by -17.21%, as it was increasingly converted for residential, commercial, and institutional purposes. Water bodies are also reduced by about -17.52% due to seasonal variation, climate change, and human interventions. Therefore, this study highlights urban expansion in Kargil Town, which threatens the already fragile ecosystem of the region. Unplanned urbanization and land use changes are expected to keep applying pressure on the local ecosystems, thus threatening biodiversity, water regime, and overall environmental sustainability. The results indicate the need for land use planning and sustainable development strategies to lessen the negative effects of rapid LULC changes in Kargil Town.

Пространственное распределение сосновых лесов Кавказа

An effective approach to studying the factors of distribution of forest-forming species of the Caucasus in conditions of orographic inaccessibility of mountainous areas is a combination of the use of geoinformation systems and the theory of ecological niche in SDM distribution models. Many aspects of this approach remain controversial, including the choice of ecological predictors, the collinearity of variables, the scale effect of the study area, the formalization of biotic factors and the dispersal capacity of species in models. The aim of this study has been to identify patterns of spatial distribution of pine (Pinus sylvestris L.) forests of the Caucasus depending on the area of the analyzed territory. To formalize the biotic factor of pine forest distribution, a method has been proposed for including probability distribution maps of the detection of competing species (birch (Betula pendula Roth and B. litwinowii Doluch.) forests) in the SDM model of P. sylvestris as biotic layers. The factor of pine dispersal capacity (accessibility of territories) has been formalized through the distance from the optimal habitats of the species (areas with a sustainability threshold of 0.8), where the probability of its detection remains above 0.5. A comparative analysis of different sets of abiotic predictors with and without multicollinear variables have revealed the advantages of the model based on the ENVIREM (Environmental Rasters for Ecological Modeling) dataset limited by the VIF (Variance Inflation Factor) test. At the local level (Central Caucasus), the main predictor of the location of pine forests is the accessibility of territories of 0–3 km from optimal habitats (the contribution to the model is about 72 %). At the regional level (Caucasus as a whole), interspecific competition is of great importance (the contribution to the model is about 37 %). The least significant factors in the distribution of pine forests are the main abiotic factors (orography of the area and the temperature and water regime of the driest quarter), the equity particlpation of which in the final models does not exceed 16 %. The species has been found to have a potentially wide distribution in the Caucasus in areas with diverse climatic and orographic conditions (about 21 thousand km2). The centre of the Caucasian pine range is predicted to be in the Central Caucasus (96 % of the optimal habitat area).

Effects of Burial Depth, Watering Regime and Soil Amendments on the Establishment of Four Arid Zone Species

ABSTRACTDirect seeding of restorative plants is a difficult task in arid environments due, in part, to the low moisture levels inherent to these areas. This barrier to restoration has stimulated a number of methods to help combat this issue, including the burial of seeds just below the soil surface, the addition of fertiliser and the use of other suitable low‐cost soil amendments aimed at improving germination and survival. This study examines the effects of burial depth and application of soil amendments on seedling emergence under different watering regimes on four semi‐arid zone species. The soil amendments used were hydrogel (EarthCare Water Crystals), fertiliser (Osmocote), and a commercial soil microbial inoculant (Bactivate5). It was found that, while heavier seeded species were able to emerge from deeper below the soil surface, all seeds in the study preferred to emerge from shallow burial depths of around 6–10 mm. Soil amendments were shown to have minimal effect on emergence rates, regardless of the watering regime, while the watering regime was found to have the largest impact. Seedlings under a low watering regime (30% water holding capacity) were found to have the lowest emergence rate, while a moderate watering regime (55% water holding capacity) produced the highest emergence across most species. Results obtained from this study suggest that shallow burial of seeds 6–10 mm below the soil surface, as opposed to surface placement or deeper burial, may enhance emergence for the species tested. Although the soil amendments did not improve plant species emergence, amendment application may still be beneficial for developing seedlings by enhancing seedling resilience to adverse growing conditions such as moisture stress or extreme temperatures.

Phylogenetic relatedness predicts plant-plant nitrogen transfer better than the duration of water scarcity periods.

Intermittent water availability is a significant stress factor for plants, particularly in arid and semi-arid ecosystems. Plant nutrient demands often do not align with precipitation pulses that trigger nutrient mobilization and availability, but biotic interactions like plant facilitation (e.g. through nitrogen transfer among distant relatives) and mycorrhizal symbiosis may mitigate this asynchrony, enabling nutrient access despite temporal disparities. We conducted a field experiment with 324 plant individuals to test two hypotheses: (1) greater mycorrhizal fungi abundance increases the amount of 15N transferred between plants, particularly under conditions of fluctuating water availability, and (2) the amount of 15N transferred is affected by the phylogenetic relatedness between donor and receiver plants. We show that 15N transfer is prevalent in the studied semi-arid communities, occurring between all species pairs in 68% of the trials. Interestingly, we observed an increase in 15N transfer between distantly related species, and this phylogenetic pattern remained consistent across fungicide and water regime treatments, which did not affect 15N transfer. Elucidating the drivers of N transfer between plants under different environmental conditions can improve our predictions on how plant communities will respond to future climate challenges, especially prolonged droughts in Mediterranean ecosystems.

Arbuscular Mycorrhizal Fungi Inoculation and Water Regime Effects on Seedling P Uptake by Rice and Pearl Millet

Mycorrhizal-mediated seedling establishment may reduce dependency on chemical fertilizers, but the effectiveness of infection for growth may differ depending on species with different eco-physiological adaptations. The infection of arbuscular mycorrhizal fungi (AMF) and P uptake were compared between rice (Oryza sativa L.) (Koshihikari (ricek), Togo4 (ricet)), and pearl millet (Pennisetum glaucum (L.) R. Br.) (ICMB89111 (millet891), ICMB95444 (millet954)) seedlings (i) in response to three different commercial AMF inoculants of Rhizoglomus irregulare (popular inoculant Dr. Kinkon (I1); two new inoculants Rootella P (I2) and Rootella F (I3)) in comparison with indigenous AMF from Andosol upland and paddy topsoils (Exp. 1–2 as the inoculant experiments) and (ii) across different water regimes from upland to flooded lowland conditions for I1 inoculant (Exp. 3–4 as the water regime experiments). The new inoculants I2 and I3 with higher propagule numbers showed a higher infection rate than the control seedlings in both rice and pearl millet, with a tendency for slower leaf development and no seedling growth enhancement. I1 inoculant had more significant positive effects on the root transversal area and shoot growth parameters than the control. The infection rates of all three inoculants were lower than the indigenous AMF from upland Andosol in rice and pearl millet, in which a higher infection rate led to higher P uptake found in millet954. I1 inoculant increased the infection rate in pearl millet and rice but had no clear indication of interaction with water regimes. A higher infection rate led to higher P uptake and shoot dry weight in pearl millet but not in rice with higher root length density. This study provided the significance of inoculants for seedling establishment and highlighted more mycorrhizal-mediated P uptake in pearl millet than in rice.

Study of the influence of iron and copper ions on oxidation processes at different temperatures using hydrazine reagent

Water treatment problems are very relevant in the operation of boiler plants and heating systems, both in small boiler houses, large enterprises, and energy facilities. The main cause of internal corrosion of equipment and pipelines of water heating systems is the presence of corrosive gases (oxygen and carbon dioxide) dissolved in water. This leads to economic costs, disruption of process technology, and also increases the anthropogenic load on the environment. Therefore, high requirements are imposed on these water regimes for desalination and deoxygenation, which allows to reduce the aggressiveness of water, prevent the formation of scale, corrosion of pipes and devices in the water supply system, and reduce the withdrawal of clean water from surface and underground sources. Deoxygenation of water is an important method for reducing metal corrosion, since oxygen is one of the main agents contributing to corrosion processes. Water containing dissolved oxygen can actively interact with metals, causing their oxidation and destruction. Reducing the concentration of oxygen in water helps to significantly slow down these processes. To reduce the oxygen concentration in water, or completely remove it from the system, a fairly large number of methods can be used – physical, chemical, physico-chemical and combined. Hydrazine hydrate is successfully used for water treatment of both drum and direct-flow boilers. The reaction rate depends on the temperature, pH of the medium, excess hydrazine according to the law of mass action, and the presence of catalysts. At temperatures below 30 °C, hydrazine practically does not interact with O2, but at 105 °C, pH 9–9.5, and an excess of hydrazine, the time for almost complete oxygen binding is several seconds. Based on experimental data, dependences were obtained that demonstrate the kinetics of changes in oxygen concentration over one hour. Initially, a study was conducted of the change in oxygen concentration upon addition of hydrazine hydrate when the experimental temperature changed from 15 to 40 °C. Studies of changes in the oxygen concentration in water with the addition of hydrazine hydrate and iron and copper ions and at different temperatures showed that the doses of hydrazine and temperature have the greatest impact on the deoxidation processes, while iron and copper ions almost did not make significant changes to the course of the process. When using iron (II) ions in a composition with hydrazine hydrate at elevated temperatures, an increase in removal efficiency by 30–40 % is noted, and the time to reach zero concentration at maximum doses is reduced by approximately 90 %. Copper (I) ions did not show catalytic properties in compositions with hydrazine hydrate at low temperatures in deoxidation processes and almost did not affect the rate of reaction with oxygen.

АНАЛИТИЧЕСКИЙ ОБЗОР ИССЛЕДОВАНИЙ ПРОРЫВНЫХ ГЛЯЦИАЛЬНЫХ СЕЛЕЙ В КАЗАХСТАНЕ

The intensification of glacial lake outburst floods (GLOFs) in Kazakhstan during the second half of the last century, against the backdrop of modern glacier degradation, has drawn significant attention from researchers to this natural phenomenon. Numerous surveys conducted in the aftermath of debris flow disasters have shown that the majority of these hazardous natural events were caused by the outbursts of glacial lakes. The primary aim of this review is to create an anthology of research on GLOFs through retrospective, situational and object-based analyses. The situational analysis considered specific events that led to catastrophic GLOFs, arranged in chronological order. The object-based analysis was carried out in various research directions, with the focus on scientific publications that directly addressed the genesis of glacial lakes, their water regimes, the structure of lake dams, the mechanisms of glacial lake outbursts, as well as forecasts and preventive measures against debris flows. The review highlights the significant role of research that has fundamentally contributed to the development and deepening of knowledge in this specific field of Earth sciences.

ПРОГНОЗ ВОДНОСТИ ОЗЕР ГОСУДАРСТВЕННОГО НАЦИОНАЛЬНОГО ПРИРОДНОГО ПАРКА «БУРАБАЙ» ДО 2050 ГОДА С УЧЕТОМ КЛИМАТИЧЕСКИХ ИЗМЕНЕНИЙ

The work is devoted to the assessment of the current state and long-term forecast of intra-century water fluctuations in the lakes of the State National Natural Park “Burabai” hereinafter (SNNP “Burabai”). On the basis of reanalysis data and results of numerical modeling, the analysis of the influence of climatic changes in the basins of lakes Shortandy, Burabai, Ulken Shabakty, Kishi Shabakty, Katarkol, Zhukey has been carried out. The linkage of a number of atmospheric and oceanic circulation indices describing climatic variability in the region with the water regime of lakes was assessed. Causal relationships between climatic characteristics and hydrological regime of catchments and water balance of lakes were investigated. Dynamics of precipitation, temperature, runoff and evaporation in the watershed in retrospect and prospect. The results of calculations show a possible reduction in moisture transport and precipitation reduction in the study area in the next 15-25 years, resulting in a delayed decline in lake water levels. Approximately from 2030 to 2050, an increase in evaporation is expected, which should lead to a lowering of the level of these water bodies.

Diagnostics of hydrological properties of soils of the Sambian plains based on aerial photography and electromagnetic induction

The article focuses on studying the influence of the spatial heterogeneity of lithological and geomorphological conditions on the hydrological characteristics of the soils of the Sambian Plain using aerial photography and electromagnetic induction methods. From 2020 to 2022, at the “Pereleski” test site, topographic surveys were conducted using UAV, soil-forming material heterogeneity was diagnosed, and field measurements of particle size distribution, moisture content, and the degree of gleyization were carried out in reference soil profiles (n = 4). Additionally, the morphology of soil horizons and the degree of gleyization in additional sampling points (n = 18) were described. The method of electromagnetic induction profiling using the EM38-MK2 established a reliable strong correlation between silt content and apparent soil electrical conductivity (R² = 0.88). Multidimensional scaling enabled the ranking of all soil descriptions at the test site by the degree of gleyization, providing a quantitative assessment of the depth and duration of waterlogging in soil profile. Morphometric characteristics and electrical conductivity in the layers of 0–0.375 m; 0–0.75 m; and 0–1.5 m were compared with the calculated gleyization intensity index of soils. Linear regression analysis revealed a relationship that explains 81% of the variability in soil gleyization based on two factors: electrical conductivity in the 0–1.5 m layer and the topographical positional index within a 10 m radius. Consequently, soils were ranked according to the combined characteristics in a sequence of increasing gleyization intensity: Endogleyic Cambisols – Gleyic Albeluvisols– Haplic Gleysols, linked to the differences in their long-term average water regimes. The identified heterogeneity of micro- and mesorelief and the high variability of the soil-forming materials resulted in the alternation of these soils in the form of soil micro-mosaics, indicating the intra-field heterogeneity of the agroecological conditions of the test site.

Plant Nitrogen Assimilation: A Climate Change Perspective.

Of all the essential macronutrients necessary for plant growth and development, nitrogen is required in the greatest amounts. Nitrogen is a key component of important biomolecules like proteins and has high nutritive importance for humans and other animals. Climate change factors, such as increasing levels of carbon dioxide, increasing temperatures, and increasing watering regime, directly or indirectly influence plant nitrogen uptake and assimilation dynamics. The impacts of these stressors can directly threaten our primary source of nitrogen as obtained from the soil by plants. In this review, we discuss how climate change factors can influence nitrogen uptake and assimilation in cultivated plants. We examine the effects of these factors alone and in combination with species of both C3 and C4 plants. Elevated carbon dioxide, e[CO2], causes the dilution of nitrogen in tissues of non-leguminous C3 and C4 plants but can increase nitrogen in legumes. The impact of high-temperature (HT) stress varies depending on whether a species is leguminous or not. Water stress (WS) tends to result in a decrease in nitrogen assimilation. Under some, though not all, conditions, e[CO2] can have a buffering effect against the detrimental impacts of other climate change stressors, having an ameliorating effect on the adverse impacts of HT or WS. Together, HT and WS are seen to cause significant reductions in biomass production and nitrogen uptake in non-leguminous C3 and C4 crops. With a steadily rising population and rapidly changing climate, consideration must be given to the morphological and physiological effects that climate change will have on future crop health and nutritional quality of N.

Effects of Different Watering Regimes on Growth, Yield and Photosynthetic Ability of Some Mungbean [<i>Vigna radiata</i> (L)] Cultivars

Effects of Different Watering Regimes on Growth, Yield and Photosynthetic Ability of Some Mungbean [<i>Vigna radiata</i> (L)] Cultivars

Drainage and nitrogen enrichment facilitate the encroachment of woody plants at various developmental stages in freshwater marshes

Abstract Woody plant encroachment into graminoid‐dominated freshwater marshes is a widespread phenomenon globally, yet the mechanisms driving it are not well understood. It is often presumed that the establishment of woody plants—encompassing seed germination, seedling survival, and seedling growth—is influenced by environmental changes such as alterations in water regimes and nutrient availability. However, this hypothesis has not been rigorously tested through empirical studies. In this study, we conducted a 3‐year common garden experiment in a freshwater marsh in northeastern China to investigate the separate and combined effects of water and nitrogen levels on woody plant establishment in a graminoid‐dominated vegetation. The experiment involved manipulating water levels (flooded vs. drained) and nitrogen concentrations (ambient vs. added) in a fully crossed factorial design to examine their individual and combined effects. We sowed seeds of seven woody species under each treatment combination and tracked their germination, seedling survival, growth and potential competitive interactions with the resident vegetation. This approach allowed us to assess the direct effects of water and nitrogen on woody plant establishment, as well as any indirect effects mediated by changes in the resident plant community. The results show that drainage in the first year significantly improved both seed germination and seedling survival of woody plants, and these survival benefits persisted over the following years. The structural equation model revealed that drainage indirectly facilitated seedling survival by reducing light asymmetry. In contrast, continuous flooding over 3 years resulted in complete seedling mortality. However, after 3 years of drainage, the addition of nitrogen significantly increased the leaf count, maximum height, and stem diameter of the surviving woody plants. Synthesis. This multispecies introduction experiment has demonstrated that water regime is the primary factor driving the establishment of woody plant seedlings in freshwater marshes. As seedlings mature, nutrient supplementation can accelerate their development, potentially facilitating their encroachment into freshwater marshes. By demonstrating the distinct and varying impacts of water and nitrogen treatments across different stages of woody plant establishment, our study offers valuable insights into the complex interplay of environmental factors shaping this phenomenon.

Responses of hybrid bell pepper in the open field with the use of hydrogel and different water regimes

Responses of hybrid bell pepper in the open field with the use of hydrogel and different water regimes

Foliar Application of γ-Polyglutamic Acid Enhances Growth, Yield, and Rhizosphere Microbiota of Summer Maize Under Varied Water Regimes

Foliar Application of γ-Polyglutamic Acid Enhances Growth, Yield, and Rhizosphere Microbiota of Summer Maize Under Varied Water Regimes