Increasing Water Salinity Research Articles

Non-stationary and unequally spaced NDVI time series analyses by the LSWAVE software

ABSTRACTChange detection within non-stationary and unequally spaced remote sensing time series has become a key methodology for a broad range of environmental applications. A new method of analysing vegetation variation over lands is proposed. Four regions in northern Tunisia with various characteristics are selected, and a non-stationary and unequally spaced Normalized Difference Vegetation Index (NDVI) time series is obtained for each region since 2000. The Landsat 7 remote sensing satellite imagery with insignificant cloud-shadow coverage is used to calculate the NDVI after atmospheric correction. The Least-Squares Wavelet (LSWAVE) software is implemented to rigorously analyse each NDVI time series and study the relationship between the vegetation of olive trees and temperature/precipitation in one of the regions. To investigate possible effects of temperature on the green cover caused by increasing water salinity, the coherency between the NDVI and sea surface temperature time series is also shown in the region of Lake Ichkeul in Tunisia.

Proline and agronomic production responses of different barley cultivars to salinity stress : A correlation analysis

Salinity affects crop growth and development, and markedly leads to observable losses in agronomic yield. Barley is considered as an excellent model crop for the prediction of crop response to climate change and as a salt tolerance crop. The main objective of this study was to identify the correlation magnitude (r) between salt stress level and both agronomic parameters and proline accumulation in barley leaves. Twenty-eight barley genotypes were exposed to salt stress, ranging from 0.85 to 16 dS/m. This simple approach will help agronomist and farmers to predict plant response under different soil salinity levels. The following agronomic parameters were recorded: proline accumulation (mg/kg), plant height (cm), grain yield (g/plant), harvest index (%), biological yield (g/plant) and straw yield (g/plant). For the purpose of data fitting and simplicity, a simple linear regression analysis was used. The results of this study showed that agronomic parameters in barley had moderate to strong correlation coefficients ranging from 0.67 to 0.98. Reduction rates in agronomic parameters were 0.799 cm, 0.079 g/plant, 0.007%, 0.67 g/plant and 0.036 g/plant per one dS/m increment of salt stress on plant height, grain yield, harvest index (%), biological yield and straw yield, respectively. This study also showed that per one unit increase of water salinity, proline accumulation increased by 1.49 mg/kg. It can be concluded from this study and under the current growing conditions, agronomic parameters and proline accumulation in examined barley genotypes are well correlated with increasing the level of salt stress.

PHYSIOLOGICAL RESPONSE OF QUINOA TO SALT STRESS UNDER SHAD HOUSE CONDITION

Quinoa is a halophytic species emerging as a potential new crop in many regions of the world because of the nutritional composition of their seeds. This study has been carried out at the Faculty of Environmental Agricultural Science, Arish University, Egypt during the two successive growing seasons 2016/2017 and 2017/2018. The experiment has been done at the shad net house of the experimental crop farm using quinoa seedlings (one month old), which grow in pots. Seedlings have been irrigated every two days using four treatments of irrigation water (control, 100, 150, 200 mM), where control was tap water 85 mM. It was observed that vegetative parameters of quinoa seedling were significantly decreased with increasing water salinity concentration .The highest value for each of plant height, root length, number of leaves, leaf dry weight, shoot dry weight, root dry weight, water relative content was obtained with low saline control, followed by 100, 150 and 200mM which gave the lowest values in this respect. Concerning growth analysis, the maximum value for each of leaf area duration, relative growth rate, crop growth rate and net assimilation rate was achieved by control, followed by the other respected studied concentration which gave the lowest values. The obtained results cleared that the concentration of nitrogen, phosphorus and potassium, pigments decreased in plant tissue with increasing water salinity concentration. However, sodium and proline concentrations increased in plant tissue with increasing salinity concentration. It worthy to note that there were significant differences between Giza1 and Giza2 in most studied parameters.

River Water Salinity Impact on Drinking Water Treatment Plant Performance Using Artificial neural network

The river water salinity is a major concern in many countries, and salinity can be expressed as total dissolved solids. So, the water salinity impact of the river is one of the major factors effects of water quality. Tigris river water salinity increase with streamline and time due to the decrease in the river flow and dam construction from neighboring countries. The major objective of this research to developed salinity model to study the change of salinity and its impact on the Al-Karkh, Sharq Dijla, Al-Karama, Al-Wathba, Al-Dora, and Al-Wihda water treatment plant along Tigris River in Baghdad city using artificial neural network model (ANN). The parameter used in a model built is (Turbidity, Ec, T.s, S.s, and TDS in) to predict the salinity TDSout. Results showed that the effectiveness of the artificial neural network model to predicting the salinity is a good agreement between observed and the predicted value of the TDS, through the determination coefficient of the model is (0.998, 0.966, 0.997, 0.998, 0.996, and 0.996) for Al. Karkh, Sharq Dijla, Al.Karama, Al.Wathba, Al.Dora and Al.Wihda respectively. From this value can be shown that ANN is a successful tool for predicting the nonlinear equation of the salinity under different and complicated environmental case along the river.

Short Term Effects of Salinization on Compound Release from Drained and Restored Coastal Wetlands

Over the past two decades, great efforts have been made to restore coastal wetlands through the removal of dikes, but challenges remain because the effects of flooding with saline water on water quality are unknown. We collected soil samples from two adjacent coastal fen peatlands, one drained and diked, the other open to the sea and rewetted, aiming at assessing the mobility and export of various compounds. Microcosm experiments with constant flow-through conditions were conducted to determine the effluent concentrations of dissolved organic carbon (DOC), ammonium ( NH 4 + ), and phosphate ( PO 4 3 − ) during saline–fresh water cycles. Sodium chloride (NaCl) was used to adjust salinity (saline water, NaCl concentration of 0.12 mol L−1; fresh water, NaCl concentration of 0.008 mol L−1) and served as a tracer. A model analysis of the obtained chloride ( Cl − ) and sodium ( Na + ) breakthrough curves indicated that peat soils have a dual porosity structure. Sodium was retarded in peat soils with a retardation factor of 1.4 ± 0.2 due to adsorption. The leaching tests revealed that water salinity has a large impact on DOC, NH 4 + , and PO 4 3 − release. The concentrations of DOC in the effluent decreased with increasing water salinity because the combination of high ionic strength (NaCl concentration of 0.12 mol L−1) and low pH (3.5 to 4.5) caused a solubility reduction. On the contrary, saline water enhanced NH 4 + release through cation exchange processes. The PO 4 3 − concentrations, however, decreased in the effluent with increasing water salinity. Overall, the decommissioning of dikes at coastal wetlands and the flooding of once drained and agriculturally used sites increase the risk that especially nitrogen may be leached at higher rates to the sea.

Composition and structure of macrozoobenthos of lakes in different natural zones and subzones of Western Siberia

In 2003–2016, the composition and structure of macrozoobenthic communities of 49 lakes in three natural zones (taiga, forest-steppe, and steppe) of Western Siberia were investigated. The benthic fauna of the research lakes includes 160 species of nine classes of invertebrates. The trophic structure was characterized, and six major trophic groups were identified. A spatial analysis of the macrozoobenthos of the research lakes showed that from the forest-steppe to the dry steppe subzone, the species diversity decreases on a considerable scale and also dominant taxa of macrozoobenthos change with increasing water salinity. Especially in the forest-steppe and steppe zones, high water salinity is probably a limiting factor in the development of macrozoobenthic communities. In the taiga zone, however, water salinity seems not to have such significance; rather the degree of humification (shown as dark-colored water due to waterlogging) should be taken into account.

Subtropical mangrove wetland is a stronger carbon dioxide sink in the dry than wet seasons

Coastal mangrove wetlands have an excellent potential in sequestrating atmospheric carbon dioxide (CO2) owing to their high primary productivity as well as slow anaerobic decomposition of organic matter. Yet, there is hitherto a paucity of researches examining the temporal variations and environmental controls of ecosystem-scale CO2 fluxes in subtropical mangroves using quasi-continuous, high temporal resolution measurements. In this study, we measured the net ecosystem CO2 exchange (NEE) between the atmosphere and a subtropical estuarine mangrove dominated by Kandelia obovata using an eddy covariance system for two full years to investigate the seasonal variability and key biophysical drivers of NEE. During the wet seasons, the magnitude of increase in ecosystem respiration (Re) was greater than that in gross primary productivity (GPP) owing to a combination of higher temperature and lower percentage of inundation, tidal height and water salinity, which subsequently resulted in an overall decrease in net CO2 uptake as compared to the dry seasons. Our results of path analysis showed that temperature was a dominant control of the temporal variations in CO2 flux during the wet seasons, while its influence became weaker during the dry seasons. On the other hand, an increase in water salinity during the dry seasons had a positive influence on GPP, which was likely related to a greater availability of ions (mainly Cl− and Na+) in supporting photosynthesis by mangrove trees in this coastal wetland with relatively low salinity (∼5–15 ppt). Our subtropical mangrove wetland was shown to be a significant carbon (C) sink, with annual C uptake rates of 890 and 758 g CO2-C m-2 yr−1 in the two years of study. We found a strong control of mangrove CO2 fluxes by biophysical factors such as temperature and salinity, implying that global warming and a reduction in water salinity in response to a greater river discharge could potentially reduce the C sink strength of estuarine mangroves in the subtropical regions.

Germination and initial development of Simira gardneriana M.R. Barbosa & Peixoto (Rubiaceae) seedlings under different temperatures and salinity levels

Simira gardneriana M.R. Barbosa & Peixoto (Rubiaceae) is a species exclusive to the Caatinga biome. It is used as forage, firewood, and in the construction of fence posts. Species from this biome are constantly subjected to abiotic stresses, including salt and thermal stress. Thus, we evaluated the effect of irrigation water salinity on the germination and initial development of S. gardneriana seedlings at different temperatures. The experiment used seeds with an initial moisture content of about 12.32%, arranged in a factorial scheme with eight levels of salinity, obtained by the addition of sodium chloride (NaCl), diluted in distilled water at concentrations of 0.0 (control), 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5 dS m-1, and the four temperatures 25, 30, 35, and 20-30°C, in four replicates of 25 seeds each. Salinity and temperature effects were evaluated based on germination, germination speed index, seedling shoot length, root length, shoot dry matter, root dry matter, and total dry matter. Increasing water salinity levels interfered with all variables analyzed in the germination of S. gardneriana seeds, especially at a temperature of 35°C. At temperatures of 25 and 30°C, seed germination and initial development were less affected by salinity. Simira gardneriana seeds are sensitive to salinity caused by the increase in NaCl from 1.5 dS m-1, which indicates a low tolerance of this species to saline environments. Our results show that the negative effect on the germination and initial development of S. gardneriana seedlings can be explained by the increase in salt levels and temperature, reducing their capacity to absorb water and nutrients, which indicates sensitivity responses of this species to salinity and thermal stress.

The Modern Status of Populations and Feeding Habits of the Longtail Dwarf Goby Knipowitschia longecaudata (Gobiidae) in the Don River Delta and the Eastern Part of Taganrog Bay

The size and sex composition and feeding habits of the longtail dwarf goby Knipowitschia longecaudata have been studied in the Don River delta and in the eastern part of Taganrog Bay. The maximum size of specimens has increased compared to the 1950s, which is, probably, caused by a decreasing pressure of predatory fishes. The change in the spectrum of food objects caused by the transformation of the zooplankton species structure and occurrence of marine forms as a result of an increase in water salinity has been found. The specific abundance and biomass of the species have been estimated for the first time: the maximum abundance reaches 36400 ind./ha in the eastern part of Taganrog Bay and 6700 ind./ha in the Don River delta; the biomass is 5.0 and 1.7 kg/ha, respectively. The features of the spatial and temporal distribution of the abundance and biomass of K. longecaudata have been analyzed.

Experimental Investigation of Water Temperature Influence on Suspended Sediment Concentration

Health of coastal ecosystems depends on the quantity and quality of suspended sediments brought by the rivers from land to the estuary. Behaviour of suspended sediments depends on water and sediment characteristics. Water temperature affects suspended sediment behaviour but has not been fully understood. Increase in water temperature due to global warming creates ecological issues. In the present study, influence of water temperature rise on suspended sediment concentration (SSC) has been studied under controlled laboratory conditions. Experiments were conducted in an annular flume using kaolin (d50 = 6.9 μm) at different water temperatures (T = 30o, 40o, and 50 °C) and salinities (S = 0, 1, 2, 5, and 10 g/L). Results show that both SSC and particle size increased with an increase in water temperature, but both decreased with an increase in water salinity. For S ≥ 2 g/L, the influence of water temperature on both SSC and settling velocity of suspended sediments was more significant compared to S < 2 g/L. For a unit increase in water temperature (°C), the SSC increased by 0.18%, 0.30%, 0.73%, 0.89%, 2.05% and settling velocity decreased by 1.71%, 2.15%, 3.64%, 3.17%, 3.45%, for water salinities of 0, 1, 2, 5 and 10 g/L, respectively. Empirical equations for determining the SSC at any time t and at any length L along the flow direction have been developed and verified.

How Water Quality and Quantity Affect Pepper Yield and Postharvest Quality

There are gaps in our knowledge of the effects of irrigation water quality and amount on yield and postharvest quality of pepper fruit (Capsicum annuum L.). We studied the effects of water quality and quantity treatments on pepper fruits during subsequent simulated storage and shelf-life. Total yield decreased with increasing water salinity, but export-quality yield was not significantly different in fruits irrigated with water of either 1.6 or 2.8 dS/m, but there was a 30–35% reduction in export-quality yield following use of water at 4.5 dS/m. Water quantity hardly affected either total or export-quality yield. Water quality but not quantity significantly affected fruit weight loss after 14 days at 7 °C plus three days at 20 °C; irrigation with water at 2.8 dS/m gave the least weight loss. Fruits were significantly firmer after irrigation with good-quality water than with salty water. The saltier the water, the higher was the sugar content. Vitamin C content was not affected by water quality or quantity, but water quality significantly affected antioxidant (AOX) content. The highest AOX activity was found with commercial quality water, the lowest with salty water. Pepper yield benefited by irrigation with fresh water (1.6 dS/m) and was not affected by water quantity, but post-storage fruit quality was maintained better after use of moderately-saline water (2.8 dS/m). Thus, irrigation water with salinity not exceeding 2.8 dS/m will not impair postharvest quality, although the yield will be reduced at this salinity level.

Содержание биогенных элементов в озерах Онон-Торейской котловины в период климатических флуктуаций

Using the example of brackish and saline lakes in South-Eastern Transbaikalia, the influence of low-water and high-water years on the ecological status of steppe lakes is considered. Cyclic fluctuations in climatic conditions at intervals of 27-35 years cause consistent filling and drying of lakes. The abiotic conditions associated with climatic fluctuations, as well as the intensity of the biochemical and biological processes taking place in the ecosystem, the level of organic matter introduced from the catchment area, determine the dynamics of nitrogen and phosphorus concentrations in the aquatic environment. On the basis of generally accepted hydrochemical methods, the change in the content of nitrogen and phosphorus, organic substances in the ecosystem of a number of lakes of the Onon-Torey basin (Bain-Tsagan, Tsagan-Nor, Yaksha, Naryn-Bulak, Ara-Torum, Batuy, Bain-Bulak, Balyktui, Ukshinda) was investigated and residual lakes of the Barun-Torey lake basin) in order to clarify the state of the lakes during the transitional period of low-water and high-water years. An assessment of the dynamics of physicochemical parameters revealed that climatic conditions (aridization or humidification) determined mineralization. In dry years (1983-86, 2018), the processes of evaporative concentration of salts became essential. In this regard, the mineralization is almost doubled and reaches up to 7 g / l. The interannual dynamics of nitrogen and phosphorus was characterized by a large amplitude of concentration fluctuations. A low content of total phosphorus in 1983, 1986 (low-water period) increases by 2011, with a decline by 2018. A large amplitude of fluctuations of the parameters studied is associated with the level of accumulation of organic matter in the bottom sediments of lakes of organic matter in low-water years. In the high-water years, the investigated lakes were of fishery importance. In 2018, due to a decrease in the water surface area and an increase in water salinity, the fish fauna was not found in these lakes. Conducted research is necessary for planning water use of lakes.

СОДЕРЖАНИЕ ТЯЖЕЛЫХ МЕТАЛЛОВ В РЫБЕ ИЗ МИНЕРАЛИЗОВАННЫХ ВОДОЕМОВ УРАЛА

The article presents the results of comparative analysis of contamination with heavy metals of fish within the framework of comprehensive, expanded ecotoxicological monitoring of freshwater and mineralized lake farms of the Southern Urals with varying degrees of anthropogenic load. At this stage, 3 reservoirs with varying degrees of salinity were studied: Mayan, Kurakli-Mayan and Sugoyak. Atomic absorption spectrophotometric method determined the content of 8 heavy metals in the bone and muscle tissue of various fish species. It was found that in muscle tissue, maximum concentrations were noted for iron and zinc, which are necessary for normal functioning of fish. Manganese and cobalt were the most variable in the composition of muscle tissue. It is shown that detected concentrations of heavy metals are within the previously established values for the reservoirs of Chelyabinsk region. The number of studied normalized elements (Pb, Cd) did not exceed the established maximum values for fish and fish products. Increased water salinity in the studied lakes is not an obstacle to their use in fisheries purposes.

REE in waters and bottom sediments of salt lakes of Southeastern Transbaikalia, Russia

This paper presents our analysis of the distribution of REE in mineral chloride and soda lakes of Southeastern Transbaikalia. With increasing water salinity, it was determined that concentrations of dissolved HREE increased. The prevalence in absolute concentrations of MREE and HREE was observed in lakes with the development of bacterial processes (sulfate-reduction). A geochemical barrier for accumulating the LREE in the waters can be fluoro-carbonates. The saturation degree of fluorcarbonates in soda lakes can be several orders higher than in chloride lakes. Under oxidizing conditions Ce(OH)4 can be formed and, in a reducing environment – Ce(OH)3.

Feasibility of Saline Gradient Solar Ponds as Thermal Energy Sources in Saskatchewan, Canada

Advancement of renewable energy is critical for sustainable development. This paper evaluates the feasibility of saline gradient solar ponds (SGSP) as an alternative energy source for Saskatchewan, Canada. The main achievements include global appraisal of SGSP from theoretical and practical perspectives, assessment of salinity and climatic criteria for SGSP potential, understanding of heat transfer mechanisms affected by thermophysical properties, and numerical modeling to simulate transient heat diffusion in SGSP. Results indicated that Saskatchewan is ideal for thermal energy harvesting from saline water bodies because of high solar insolation (1100 to 1400 kWh/m2). The solar radiation in such systems is captured under a salt concentration gradient. Locally, ten potash tailings sites (360 g/L or 36% salt) and two saline water lakes (250 g/L or 25% salt) are potentially suitable for SGSP deployment. It was found that thermal conductivity increases with temperature but decreases with water salinity increase (0.55 to 0.675 W/mK) and the opposite is true for density (1000 to 1200 kg/m3). Similarly, specific heat capacity slightly increases with temperature and inversely correlates with salinity (3000 to 4200 J/kg K). Furthermore, the heat diffusion model adequately simulated the temperature distribution for a typical SGSP in a potash tailings containment facility. For the investigated month of July (highest solar insolation), the temperatures increased from an initial value of at 20 to 52 oC at top to 37 oC at bottom. A comprehensive risk assessment of this method is required to protect air, water, soil, and biota at specific sites.

Photosynthetic pigments and photochemical efficiency of precocious dwarf cashew (&lt;i&gt;Anacardium occidentale&lt;/i&gt; L.) under salt stress and potassium fertilization

Cashew cultivation is an activity of great socioeconomic relevance, especially for agriculture in the semi-arid region of Northeast Brazil, standing out as an option to generate jobs and income. Thus, the present study aimed to evaluate the photosynthetic pigments and photochemical efficiency of precocious dwarf cashew under salt stress and potassium fertilization. The study was conducted using a Regolithic Neosol with sandy loam texture, adopting a randomized block design in 5×2 factorial arrangement, which corresponded to five levels of electrical conductivity of irrigation water—ECw (0.4; 1.2; 2.0; 2.8 and 3.6 dS m-1) associated with two doses of potassium fertilization—KD (100 and 150% of recommendation), with three replicates and two plants per plot. Increasing water salinity inhibited chlorophyll synthesis and decreased electron transport rate and quantum yield of non-regulated energy dissipation in precocious dwarf cashew, at 50 days after sowing. There was significant interaction for chlorophyll a and b contents and the effects of salt stress were intensified by potassium doses on the chlorophyll b content of precocious dwarf cashew. Potassium doses of 100 and 150% of recommendation (150 and 225 mg K2O kg-1 of soil) do not mitigate the effect of salt stress on photosynthetic pigment synthesis and photochemical efficiency of cashew plants in the rootstock formation phase.

PHYSIOLOGICAL INDICES AND GROWTH OF ‘PALUMA’ GUAVA UNDER SALINE WATER IRRIGATION AND NITROGEN FERTIGATION

ABSTRACT The cultivation of irrigated guava in semi-arid areas highlights the need for information regarding its responses to irrigation water quality and the fertilization management that enables its exploitation. Thus, this study aimed to evaluate the effect of water salinity and nitrogen (N) doses on the growth and physiology of the guava cv. ‘Paluma’. The experiments was conducted in drainage lysimeters under field conditions in an experimental area at the Center of Sciences and Agri-Food Technology of the Federal University of Campina Grande (CCTA/UFCG), Campus II, in Pombal, PB, Brazil. The experiment had a randomized block design, and treatments consisted of a 5 x 4 factorial arrangement corresponding to five levels of irrigation water electrical conductivity, ECw (0.3, 1.1, 1.9, 2.7, and 3.5 dS m-1), and four N doses (70, 100, 130, and 160% of the recommended N dose). The 100% dose corresponded to 541.1 mg of N dm-3 of soil. Increments in irrigation water salinity from 0.3 dS m-1 led to a reduction in stomatal conductance, internal CO2 concentration, CO2 assimilation rate, transpiration, instantaneous water use efficiency, the number of leaves and branches, stem diameter, and absolute and relative growth rates. Nitrogen doses ranging from 378.7 to 865.7 mg of N dm-3 of soil did not affect gas exchange and plant growth. Although ‘Paluma’ guava growth was affected by increases in water salinity, these plants can be irrigated using water of up to 1.42 dS m-1 with an acceptable reduction of 10% in growth variables. The interaction between irrigation water salinity and N fertilization had no significant effect on any of the variables studied.

THE EFFECT OF DIFFERENT WELL WATER QUALITY AND IRRIGATION METHODS ON SOME CHEMICAL PROPERTIES AND SALINITY DISTRIBUTION OF SOIL IN ARID AREAS: A CASE STUDY OF ISMAILIA GOVERNORATE

The increasing demand for irrigation water to secure food for growing populations with limited water supply suggests re-thinking the use of non-conventional water resources. The study was conducted to monitor the salinity distribution in soil under different well water quality and irrigation methods in specific sites of Ismailia Governorate region. Water and soil samples were collected from hundred randomly selected sites. Both soil and water samples were analyzed for chemical characteristic which included salinity, cations, anions and SAR. The findings indicated that the mean soil pH was 7.35 while the mean EC value was 3.73 dS/m. The mean cations in the water samples were 7.43, 5.98, 0.17, and 23.33 meq/l for Ca2+, Mg2+, K+, and Na+, respectively and the a mean value of Sodium Adsorption Ratio (SAR) was 9.11. The mean bicarbonates concentration detected in the irrigation water was 4.43 meq/l, while the mean chloride and sulphate were 29.95 and 2.49meq/l, respectively. The mean values of EC of soil were 3.94, 5.98 and 4.56 for drip, sprinkler and surface irrigation methods in depth 0-20 cm, respectively. While, in soil depth 20-40 cm the mean values of EC were 6.78, 4.94 and 2.99 for drip, sprinkler and surface irrigation methods, respectively. The spatial distribution of soil salinity in the soil horizons were found to be higher at shallow depths of 0-20cm and decreasing gradually up to a depth of 20-40cm. This trend is clear with surface and sprinkler irrigation method. In drip irrigated method, the salinity distribution showed a different pattern from that observed in surface and sprinkler irrigation. Salinity was the lowest in the surface layer (0-20 cm), and increased gradually with soil depth (20-40 cm). Salt concentration factor (SCF) of Ismailia soil under studies ranged between0.14 to 6.33. The results showed that SCF varies according to water and soil quality and irrigation methods.EC of soil was positively and significantly correlated with Ca2+, Mg2+, Na+ , K+, Cl-, HCO-3 but positively and not significantly correlated with pH andSO2-4.The general trend showed that soil salinity increased with an increase in water salinity. Correlation coefficient (r) between EC of irrigation water and EC of soil was 0.550**.

The tendencies of climate change and the runoff in the middle-lower part in the basin of Southern Bug River (in the region of location of the South-Ukrainian Nuclear Power Plant)

Feature of climate change and runoff for the middle-lower part of the basin of the Southern Bug River (in location of the South-Ukrainian Nuclear Power Plant) of the second half of the XX century and at the beginning of the XXI century are analyzed. Due to climate change, the increase of the average annual air temperature (on 0.16—0.28 °C per 10 year) and insignificant increase of annual the amount of precipitation in this region (on 1—2 %) for period 1945—2017 occurred. However, more intense warming and negative tendency decrease of annual the amount of precipitation (on 3—10 % and in summer on 20—30 %) for the last several decades at the meteostations Pervomaisk and Voznesensk and was observed. Such regional climate change can lead, to a certain extent, to the decrease of water content of the reservoirs, due anomaly increasing temperatures and decreasing precipitations in summer (July—August) and increased evaporation in basin of the Southern Bug River. Slight increase annual the amount of precipitations (and in the cold season) in this part of the basin do not compensate such negative tendency. Rather complicated and dangerous hydrological situation in the basin of the Southern Bug River and reservoirs for period 2015—2017 due to the lowest water level by period of operation of reservoirs was due to the difficult weather conditions (aridization of climatic conditions) and increased water consumption (the runoff of the Southern Bug River in August—September was about 15 % less than the monthly norm). In the delta of the Southern Bug River, there are the unfavorable situation also. So, in the Bug Liman take place: increase of water salinity, de-crease of depths, increase of water temperature, reduce of volume of fresh water flow from river intensification of the influx of salt water from the Black Sea. The regional climate change and runoff can lead to some complications in the further effective exploitation of SUNPP and probably there will be accompanied by negative environmental impact that should be avoided. Therefore, it is important to find a reasonable compromise between economic feasibility and preservation of the environment.

Growth and gas exchanges in soursop under irrigation with saline water and nitrogen sources

ABSTRACT Nitrogen (N) fertilization has been tested for the mitigation of salt stress in some species including fruit crops. However, special attention should be paid to the source of N, due to the different compositions and saline indices of the fertilizers, particularly when irrigation is conducted using waters with salinity levels that are restrictive to agriculture. Thus, this study evaluated the effect of fertilization with N sources on the growth and gas exchanges of soursop irrigated with saline water after transplanting. The experiment was carried out in greenhouse at the Center of Technology and Natural Resources of the Federal University of Campina Grande, and treatments were arranged in randomized blocks, in 4 x 4 factorial scheme, corresponding to electrical conductivity of water - 0.5, 1.1, 2.5 and 3.5 dS m-1, and the N sources urea, ammonia sulfate, calcium nitrate and potassium nitrate, with three replicates. Growth and gas exchanges of soursop at 110 days after transplanting were not influenced by either the interaction between water salinity and N sources or the individual action of N, but were inhibited by the increase in water salinity from 0.5 dS m-1. Increasing water salinity inhibited stomatal opening and carboxylation in the leaves.