Risk Of Salinization Research Articles

Salinity and temperature increase impact groundwater crustaceans

Anthropogenic impacts in groundwater ecosystems remain poorly known. Climate change is omnipresent, while groundwater salinization poses serious long-term environmental problems in arid and semi-arid regions, and is exacerbated by global warming. Both are present threats to the conservation of groundwater ecosystems, which harbour highly specialized species, with peculiar traits and limited geographic distributions. We tested the temperature and salinity tolerance of groundwater-adapted invertebrates to understand the effect of global warming and salinization in groundwater ecosystems. We used species representative of groundwater-adapted crustaceans: two copepods (harpacticoid and cyclopoid) and one syncarid, endemic to Australia. Our results show that 50% of the populations died at salt concentrations between 2.84 to 7.35 g NaCl/L after 96 h, and at 6.9 °C above the ambient aquifer temperature for copepods and more than 10 °C for syncarids. Both copepods were more sensitive to temperature and NaCl than the syncarid. We calculated a salinity risk quotient of 9.7 and predicted the risk of loss of 10% of syncarid and 20% of copepod population abundances under a worst-case scenario of global warming predictions for 2070. These results highlight that both salinity and temperature increases pose a risk to the ecological integrity of groundwater ecosystems.

EVALUATION OF HOSEHOLD WASTEWATER AND THE POSSIBILITY OF ISOLATING IT FOR IRRIGATION IN THE CITIES OF RAMADI AND HADITHA

A field survey was carried out for the cities of Ramadi and Haditha, which included calculating water volumes and assessing their quality for the purpose of irrigation used in house according to the nature of their uses in the house. Data and samples were obtained in collaboration with volunteers from the college of Agriculture, Girls college of Education and some of the residents of Ramadi, of the Basic Education faculty and some of the people in Haditha, and the data and samples obtained were up to 200 samples. The study showed the possibility of isolating the water used for domestic purposes from the water cycles and the possibility of reusing it for agricultural purposes as it became clear that the wastewater other than the toilets fall within the category C3S1 according to the USA classification, while the FAO classification of high quality to cause salinity risk and he study also proved that at least 65% can be reclaimed for irrigation purposes, equivalent to 389382000 m3 ,which can be harvested at the national level is 6% water deficit in Iraq .

Land use/land cover assessment as related to soil and irrigation water salinity over an oasis in arid environment

AbstractThe land use and land cover (LULC) changes and the implications of soil and irrigation water salinity have adverse effects on crop production and the ecosystems of arid and semiarid regions. In this study, an attempt has been made to analyze and monitor the LULC changes using multitemporal Landsat data for years 1986, 1998, 2007, and 2016 in Al-Ahsa Oasis, Saudi Arabia. In addition, efforts were made to measure the spatial distribution of soil and irrigation water salinity along the oasis. The supervised maximum likelihood classification method was applied to classify the individual images independently. Moreover, soil samples were collected at surface soil depth from the selected LULC types, namely, date palm, croplands, and bare land. Also, groundwater samples were collected from bore wells located in agricultural farms. The spatial distribution of the soil salinity (Ece) and irrigation water salinity (ECiw) was classified based on the Food and Agriculture Organization guidelines. The results showed that significant changes in LULC patterns have occurred during 1986–2016 in the study area. The ECewas found higher in date palm compared with cropland and bare land. However, the spatial distribution of the ECiwover the oasis indicated that 94% of irrigation water ranged between moderate and severe salinity risk. The study concludes that salinity management practices need to be developed in the study area aiming to sustain crop yields, improve soil properties, and minimize the environmental impacts of LULC changes on the ecosystem of Al-Ahsa Oasis.

Optimization of Ozone Application in Post-Treatment of Cattle Wastewater from Organic Farms

In this study, an advanced oxidation process using ozone application in a fixed-bed reactor filled with bio-rings was used for purification and disinfection of cattle wastewater (CWW) previously treated in a UASB reactor. The O3 concentration applied to the reactor was 7.8 mg L−1 (±1). Four ozonation times were tested in a batch process: T1 = 0.5 h, T2 = 1 h, T3 = 1.5 h and T4 = 2 h. The pH values tended to increase with the time of contact between liquid and gas. COD and BOD5 removal of 55 and 64% was recorded in T4. Color and turbidity were reduced by 88.5 and 93.4%, while total solids and total suspended solids were reduced by 65.7 and 93.5%, respectively. Oils and greases were completely removed from the wastewater. Electrical conductivity did not vary significantly between treatments, and its association with the presence of cations, such as Na+, Ca2+ and Mg2+, suggests good quality of the water ozonated in T4 for application in the soil, with no risk of salinization. High concentrations of nitrogen compounds were removed, but the efficiency in removing phosphate compounds was low. Coliform removal of above 99% was achieved with T3. Only the CWW ozonated in T4 is recommended for irrigation of raw-consumed crops. Based on most parameters analyzed, the CWW treated in T4 would also be suitable for discharge into water bodies according to Brazilian legislation, suggesting that this technology could be applied in the near future.

Disponibilidade e qualidade da água para irrigação no território indígena Rio Formoso, na transição cerrado/Amazônia, Mato Grosso-Brasil

O objetivo deste trabalho foi quantificar e qualificar a água para a irrigação nos mananciais da Terra Indígena Rio Formoso em Tangará da Serra, Mato Grosso – Brasil, no contexto de importante polo agrícola brasileiro. Delimitaram-se cinco bacias hidrográficas com cinco pontos de coleta e amostragens em 12 meses seguidos, a partir de agosto/2016. Foram avaliadas 15 variáveis: nitrogênio (N), fósforo (P), temperatura (T), turbidez (Tu), sólidos totais (ST), potássio (K+), cálcio (Ca2+), magnésio (Mg2+), cloretos (Cl-), bicarbonatos (HCO3-), condutividade elétrica (CE), potencial hidrogeniônico (pH), coliformes termotolerantes (C.T.), alcalinidade (Alc) e sódio (Na+) e calculada a razão de absorção de sódio (RAS) e a dureza (Du GHF). Os resultados revelaram risco nulo de salinização, toxidade e risco severo de sodificação. O potencial hidrogeniônico é baixo e a temperatura da água ficou acima de 25 ºC. A concentração de coliformes termotolerantes em três pontos prejudica o cultivo de folhosas que são consumidas cruas. As desconformidades encontradas indicam que o uso da água deve ser feito com acompanhamento técnico especializado para evitar danos irreversíveis ao solo e equipamentos. Não há limitação de quantidade de água com vazão disponível outorgável de 1,884 m³ s-¹.

Decrease of both river flow and quality aggravates water crisis in North China: a typical example of the upper Yongding River watershed.

Due to unevenly distributed water resources, semi-arid regions are particularly prone to severe water shortage and quality degradation. In this study, based on long-term hydrological database (1935-2015), and the latest available water quality data sets (2011-2016), we analyzed the water crisis and its driving forces in the upper Yongding River watershed, a typical water shortage area in North China. The results showed that human induced excessive water consumption is responsible for the significantly decreased river flow over the past eight decades. Although the capacity of the watershed wastewater treatment has improved, current water quality does not meet the requirements of the national water management goals, because of the excessive nitrogen and CODCr (chemical oxygen demand), which mainly come from the wastewater and feedlots discharge. Due to the decreased river flow, current Yongding River is unable to dilute and assimilate pollutions. The analysis of river pollutant load illustrated that more than 60 % of the nitrogen in the river water system is diverted for reservoir storage, and more than 50 % of the CODCr and TP are diverted for irrigation, thereby, increasing the risk of reservoirs eutrophication and threatening food safety. Besides, the high Cl- (388.2 ± 322.5 mg/L) and SO42- (470.6 ± 357.7 mg/L) imply that the upper river water are not suitable for drinking and irrigation purposes, and a potential risk of salinization if the river flow continues to decrease. We conclude that water resources over extraction and quality degradation are the main driving factors of the Yongding River water crisis.

Simulation of Water and Salt Dynamics in the Soil Profile in the Semi-Arid Region of Tunisia—Evaluation of the Irrigation Method for a Tomato Crop

In Tunisia, water used for irrigation is often saline, increasing the risk of salinization for soils and crops. In this study, an experiment was conducted on a tomato crop cultivated on a silty-clay soil irrigated with three different water qualities: 0, 3.5, and 7 dS·m−1. Experimental data were then used to calibrate and validate the Hydrus-1D model, which simulates water flow and salt transfer in soils. The successfully-calibrated and validated model was then used to study the combined effects of the soil osmotic and soil matrix potentials on root water uptake. The values of the root mean square error (RMSE), the coefficient of determination (CD), the modeling efficiency (EF), and the coefficient of residual mass (CRM) were close to their optimal values for both soil water content and soil electrical conductivity profiles, indicating the reliability of the model to reproduce water and salt dynamics. Relative yields (Yr), indirectly estimated using actual and potential root water uptake (transpiration), indicated that the multiplicative stress response model (using the S-shape model) satisfactorily simulates measured yields and reproduces the effects of irrigation with saline waters on crop yields. An alternative scenario using a reduction of water requirements by 50% was investigated to assess an irrigation method with considerable water savings. As the results show that relative yields, Yr, were only slightly reduced, the crop water requirements estimated by CROPWAT 8.0 must have been overestimated. The variation of the soil salinity in the root zone highlighted a high salinization risk in the short-term when water of 7 dS·m−1 is used for irrigation.

Modeling salt redistribution and plant growth in reclaimed saline-sodic overburden upland forests: A case study from the Athabasca Oil Sands Region, Canada

Migration of salts from overburden/mine spoil with elevated salinity and sodicity into placed soil reclamation cover materials can adversely affect forest growth. In this study, we explored whether the ecosystem model ecosys which uses water potential and salt concentration gradients to simulate lateral and vertical water and solute fluxes can be used to determine the effects of salt redistribution on plant productivity in reclaimed landforms. In this study, salt transport and consequent effects on plant growth were simulated and tested against electrical conductivity (EC) and plant growth measured with soil cover depths of 35 cm, 50 cm and 100 cm in a 17-year-old forest reclamation site on a slope constructed on saline-sodic overburden in Northern Alberta. Overall, results from this study demonstrated the applicability of ecosys in predicting salinity effects on forest productivity in reclaimed landscapes. The modelled results showed that the upward salt movement from overburden to coversoil was influenced by the cover depth as observed in the measured values. Upward salt movement into the covers equilibrated with modelled downslope salt discharge after nine years from reclamation, maintaining a stable EC profile in the root zone. Even though modelled aspen vs. white spruce growth was adversely affected by salinity in shallow covers (≤50 cm depth) during dry years, long-term plant productivity in all the covers did not change markedly under the current climate. A clear topographical effect on salinity in the reclamation covers was not found during the study period, although the modelled salt discharge indicated a risk of salinization in downstream areas.

Preferential Flow Enhances Pumping‐Induced Saltwater Intrusion in Volcanic Aquifers

AbstractPreferential flow can result in rapid contamination of groundwater resources. This is particularly true in aquifers with connected, high permeability geologic structures and in coastal systems where the oceanic source of contamination is ubiquitous. We consider saltwater intrusion due to pumping in volcanic aquifers with lava tubes represented as connected high‐K structures and compare salinization responses to those of heterogeneous aquifers with different structure and equivalent homogeneous systems. Three‐dimensional simulations of variable‐density groundwater flow and salt transport show that conduits formed by lava flows create preferential groundwater flow in volcanic aquifers. These conduits allow fresh groundwater to extend further offshore than in other systems. However, onshore pumping causes saltwater to migrate landward quickly through the conduits relative to the other models, resulting in more severe saltwater intrusion, particularly at shallow depths. The geometry of geologic heterogeneity in volcanic aquifers leads to increased risk of salinization of fresh groundwater as well as substantial uncertainty due to significant spatial variation in saltwater intrusion. The findings illustrate the importance of considering geologic heterogeneity in assessing the vulnerability of coastal freshwater resources in volcanic and other aquifers with connected high‐permeability geologic structures.

Short-Term Effects of Changing Soil Management Practices on Soil Quality Indicators and Crop Yields in Greenhouses

The short-term responses of soil quality indicators are important for assessing the effects of new management practices and addressing threats to crop yields in greenhouses. The aim of this study was to assess, during three consecutive cropping seasons, the effect of a sustainable management package (CRTMP)—which includes the on-site reuse of greenhouse crop residues and tillage—in comparison with conventional management, based on fertigation only (CMP), on certain biochemical soil quality indicators and crop yields. CRTMP significantly increased (p < 0.05) the values of total organic carbon (TOC), particulate organic carbon (POC), light fraction (LF), water soluble organic carbon (WSOC), and dehydrogenase (DH) and β-glucosidase (GL) activities at a depth of 0–15 cm, as well as the mean concentration of nitrates in the soil solution. In addition, a significant Pearson’s correlation (p < 0.01) found between the indicators suggested a balanced improvement of soil biological activity and nutritional soil state. Nonetheless, the significant (p < 0.05) increases in the mean concentration of chlorides in the soil solution and electrical conductivity (p < 0.05) increased the risk of salinization, which may have affected the concentration of nitrates in the petiole sap and total production in CRTMP, which were significantly lower than in CMP. Nevertheless, the proportion of premium product was significantly higher in CRTMP, while the proportion of non-commercial production decreased.

RESPONSES OF SOIL WATER‐SALT VARIATION AND COTTON GROWTH TO DRIP IRRIGATION WITH SALINE WATER IN THE LOW PLAIN NEAR THE BOHAI SEA

AbstractTo test the feasibility and sustainability of drip irrigation with saline water in the Low Plain near the Bohai Sea (BHLP) in North China, the effects of drip irrigation using saline water on soil water salt, cotton growth, seed cotton yield and fibre quality were conducted during 2017–2018. Five salinity levels of irrigation water were set up: 1.3, 5.4, 8.8, 12.4 and 15.9 dS m‾¹. Cotton evapotranspiration increased first and then decreased with increasing salinity of irrigation water. Soil ECe within the cotton root zone at each stage increased with greater salinity of irrigation water. After a 2‐year experiment soil desalination occurred in the main root layer (top 0–60 cm soil layer) when water salinity was less than 8.8 dS m‾¹. The significant (p < 0.05) decline of seedling establishment rate and seed cotton yield only occurred in 15.9 dS m‾¹ treatment in 2017 when saline water was drip irrigated right after sowing. Leaf area index and plant height were inhibited when irrigation water salinity was more than 12.4 dS m‾¹ in both years. Additionally, saline water irrigation had little effect on fibre quality. To avoid a secondary salinization risk in this region, water with the salinity level of ≤8.8 dS m‾¹ was recommended under drip irrigation. © 2020 John Wiley & Sons, Ltd.

Sugar-alcohol industry: quality of its biotreated washing water for reuse in fertigation.

All processes in agro-industries consume water and generate large volumes of nutrient-rich effluents. To recycle effluents from a sugar-alcohol industry in the Northeastern Brazil (Coruripe, Alagoas), the effect of a daily application of a microbial formulation (containing five indigenous bacteria and two fungi), at the entrance of the two first facultative ponds (D, E) of its treatment plant formed by seven ponds (A-G), was evaluated in the sugarcane harvests of 2014/2015 and 2015/2016. Fortnightly, the values of 11 physicochemical parameters were checked and statistically compared (one and two-way ANOVA) in untreated (sedimentation pond A) and post-treated effluent (last facultative pond G), during both harvests. The treated effluent presented statistically significant improvements (p> 0.05), even between harvests, with averages of removal of organic matter of ca. 79.21% and 90.62%, and increases of the dissolved oxygen (DO) of ca. 72% and 74%, as well as the average increase of pH was ca. 42% and 50%. This better quality residue generally satisfied the class III level of the Brazilian Resolution 357/2005 (National Council for the Environment (CONAMA)), for water reuse in sugarcane irrigation on the yellow clay latosol soil, since it still is a light source of organic matter, nitrites and phosphorus, reducing the need of fertilizers for maintaining the productivity with low risk of salinization. According to Pearson's bivariate correlation coefficient, while the DO and pH have positive correlation, they both have general inverse relation with the other physicochemical parameters evaluated and vice versa.

Assessment and Mapping of Soil Salinization Risk in an Egyptian Field Using a Probabilistic Approach

The assessment of soil salinization risk at the field scale requires modeling of the spatial variability of soil salinity. This paper presents a probabilistic approach to estimate and map a risk index using all available auxiliary information. A probabilistic methodology is proposed to estimate the conditional probability of exceeding the assigned threshold value of a generic indicator of soil salinity. A geostatistical non-parametric technique, probability kriging, was used to assess the risk of soil salinization and delineate different hazard zones within a field. The technique relies on indicator coding of information. The approach was applied to soil electrical conductivity measurements collected in an experimental field located in the Nile Delta region in Egypt, and submitted over time to trials with different fertilization treatments. The application of the method allowed delineation of a north-eastern zone in the field with a high risk of soil salinization due to its lack of cultivation for a long time and nearness to buildings that prevent water infiltration. The method proved to be quite promising from the perspective of precision agriculture and it is easily extendable to any sort of remote and proximal sensing auxiliary information, including information on the deepest layers of soil.

Regional and well-scale indicators for assessing the sustainability of small island fresh groundwater lenses under future climate conditions

Salinization of the freshwater lens and well fields under future climate and groundwater demands threaten the sustainability of groundwater abstraction in small islands. In this paper, two simple indices are proposed for a comprehensive assessment of freshwater salinization in small islands. Values of these indices are computed based on a sharp-interface finite element numerical model with the interface matched to the lower limit of freshwater. The first index relates rainfall percentiles with the computed freshwater volume and provides regional assessment of changes in the volume stored in the freshwater lens over time. The second is a sustainability index, based on computed saltwater ratios in pumping wells as the performance indicator, which represents the well salinization risk at a spatial scale. The proposed methodology is illustrated with the example of Tongatapu Island. Freshwater lens dynamics and well salinization under various scenarios of dry, median, and wet general circulation model predictions-based unsteady recharge, sea level rise, and pumping demands were evaluated for the period 2010–2099. The freshwater lens of Tongatapu is dependent on rainfall, and the 60-month rainfall percentile is highly correlated with the total freshwater volume. Public well field indicates sustainability indexes of 45% and 100% under the current pumping conditions for the driest and the wettest scenarios, and with increased pumping and sea level rise, they reduce to 30% and 90%, respectively. Thus, management of pumping rates is essential for future freshwater sustainability. This methodology can be used for first-hand temporal and spatial estimations of small island freshwater lens salinization considering both the regional and well scales.

Groundwater Salinity Susceptibility Mapping Using Classifier Ensemble and Bayesian Machine Learning Models

Risk and susceptibility mapping of groundwater salinity (GWS) are challenging tasks for groundwater quality monitoring and management. Advancement of accurate prediction systems is essential for the identification of vulnerable areas in order to raise awareness about the potential salinity susceptibility and protect the groundwater and top-soil in due time. In this study, three machine learning models of Stochastic Gradient Boosting (StoGB), Rotation Forest (RotFor), and Bayesian Generalized Linear Model (Bayesglm) are developed for building prediction models and their performance evaluated in the delineation of salinity susceptibility maps. Both natural and human effective factors (16 features) were used as predictors for groundwater salinity modeling and were randomly divided into the training (80%) and testing (20%) datasets. The models were evaluated using testing datasets after calibration using the selected features by recursive feature elimination (RFE) method. The RFE indicated that modeling with 8 features had better performance among 1 to 16 features (Accuracy = 0.87). Results of the groundwater salinity prediction highlighted that StoGB had a good performance, whereas the RotFor and Bayesglm had an excellent performance based on the Kappa values (>0.85). Although spatial prediction of the models was different, all of the models indicated that central parts of the region have a very high susceptibility which matches with agricultural areas, lithology map, the locations with low depth to groundwater, low slope, and elevation. Additionally, areas near to the Maharlu lake and locations with a high decline in groundwater are also located in the very high susceptibility zone, which can confirm the effects of saltwater intrusion. The susceptibility maps produced in this study are of utmost importance for water security and sustainable agriculture.

Impact Study of Impoundment of the Three Gorges Reservoir on Salt-Water Dynamics and Soil Salinity in the Yangtze River Estuary

As the largest hydropower project in China, the impact of the Three Gorges Project (TGP) on the ecological environment has aroused public attention and has been studied from various aspects. After the TGP was operated, seasonably adjusted runof f by the Three Gorge Reservoir (TGR) might cause great changes of hydrological regime in the lower reaches of the Yangtze River, especially the estuarine areas where seawater intrusion is strong and salt-water environment is complicated. The salt-water dynamics in this region will be greatly influenced in response to the operation of TGP. In order to study the impact of the project on salt -water dynamics and soil salinity, a field experiment has been carried out in the Yangtze River Estuary (YRE). This paper seeks to investigate the influence of the TGR on salt-water dynamics and soil salinity in YRE through the analysis of the relationship between the impact factors of salt - water dynamics in the estuary area. Results showed that the estuarine runoff was closely related to the impoundment process, and the estuarine runoff was one of the most important factors that influenced salinity dynamics of water and soil in the estuary. Results showed that discharge of the TGR was affected by its water storage speed, and runoff at Datong station in the estuary was significantly correlated with the reservoir discharge. The reservoir discharge affected Datong runoff and the lag time of influence of the TGR on Datong discharge is about 8 to 9 days. Runoff at Datong station influenced the river water level in the estuary, and impact of the river runoff on the river water level was delayed around 13 days. The lag time of the influence of the impoundment process of the TGR on the estuarine water level is about 20 days. The discharge decrease of the reservoir reached 3600 m3/s during the impoundment period in 2011, and it would cause about 3500 m3/s flow decline at Datong station with 8 days lag. It will result in 15.6 cm drop in the water level and 4.26 mS/cm increase in river water electrical conductivity (EC) in the estuary, which indicated the increase risk of seawater intrusion intensity in the estuary. Significantly positive correlation between river water salinity and ground-water salinity was also observed, and influence of the river water salinity on groundwater salinity increased gradually from the river bank to the inland. Significant correlation existed between groundwater salinity and soil salinity in different soil layers, with the closest relation in the deep layers. Monitoring results showed that salinity of river water, groundwater and soil under impoundment process performed higher than that of non-impoundment process, and it could be inferred that the impoundment process has a certain impact on the salt-water dynamics and soil salinity in the estuary. In summary, soil and groundwater salinity were affected by the TGR, and risk of soil salinization increased.

Optimizing water resources allocation and soil salinity control for supporting agricultural and environmental sustainable development in Central Asia

In this study, a stochastic-fuzzy-based fractional programming (SFFP) method is advanced for optimizing water-resources allocation and soil-salinity control under uncertainty. The developed method can address ratio objective optimization problems of complex system in association with stochastic and fuzzy uncertainties, which can help gain in-depth analysis of the interrelationships between marginal effectiveness and system reliability. Then, SFFP is applied to an irrigation region in the lower reach of Amu Darya River basin, where linear crop yield-salinity functions and salt-leaching functions are introduced into the modeling formulation for reflecting the complicated interactions among water resources, soil salinity, arable land, and electricity supply. Solutions under 96 scenarios related to different irrigation efficiencies, water availabilities, and electricity supplies have been obtained. Our findings are: i) increased water availability, electricity supply, and irrigation efficiency result in high marginal benefit; ii) irrigation efficiency is the key factor influencing water allocation patterns for crop irrigation and salt-leaching, promotion of which can facilitate mitigating economic and environmental losses in the water-deficit and soil-salinized region; iii) leaching water allocation patterns for soil-salinity washing is related to salinity characters of crops and regions, and boosting drought- and salt-tolerance crop can be effective in adaption to risks of water scarcity and land salinization. Compared to the conventional approaches, SFFP can generate more flexible alternatives and achieve higher marginal effectiveness. These findings can provide effective decision support to identify desired water management strategies under multiple uncertainties for supporting agricultural sustainability in arid regions.

The assessment of the physicochemical quality of water intended for irrigation of Oued Méskiana (Oum El Bouaghi) Algeria

Abstract The aquatic ecosystem of the Meskiana Valley (wilaya of Oum El Bouaghi) covers a large area with a permanent flow and a semi-arid climate characterized by a strong evapotranspiration. In order to determine the Physico-chemical quality, pollution and salinity of the water of the river of Meskiana and more particularly in its downstream part which is exposed to wastewater discharges, analyses were carried out at the level of three sampling points: witness, the upstream (before spill), downstream (after spill)). In order to prevent the risk of alkalization and salinization of soil, the sodium absorption rate (SAR) and the percentage of sodium were determined and represented on the Wilcox and Riverside diagram. The high concentrations of polluting chemical elements and excessive salinity obtained at the downstream site show a high risk of pollution and salinization.

EFEITO TEMPORAL DA UTILIZAÇÃO DE BIOSSÓLIDO E EFLUENTE TRATADO NA SODICIDADE E SALINIDADE DO SOLO

EFEITO TEMPORAL DA UTILIZAÇÃO DE BIOSSÓLIDO E EFLUENTE TRATADO NA SODICIDADE E SALINIDADE DO SOLO 
 
 
 DÁVILLA ALESSANDRA DA SILVA ALVES1; RAFAEL OLIVEIRA DE MELO2; JÉSSICA DE LIMA3; JOSÉ CARLOS COELHO4 E HÉLIO GRASSI FILHO5
 
 1Doutoranda em Agronomia: Irrigação e drenagem, Faculdade de Ciências Agronômicas (FCA/UNESP), Rua José Barbosa de Barros, 1780, CEP 18610-307, Jardim Paraíso, Botucatu/SP, Brasil. e-mail: davilla.alessandra@gmail.com; 
 2Engº Agrº, Grupo MNS, Avenida Miguel Petrere, N° 777, Pilar do Sul/S, CEP: 18185-000. Contato: (015) 3278-9000, Sorocaba/SP, Brasil.. e-mail: rafaeldemelo.net@gmail.com
 3Mestre em Agronomia: Irrigação e drenagem, Faculdade de Ciências Agronômicas (FCA/UNESP), Rua José Barbosa de Barros, 1780, CEP 18610-307, Jardim Paraíso, Botucatu/SP, Brasil. e-mail: jessik1300@hotmail.com
 4Mestre em Agronomia: Irrigação e drenagem, Faculdade de Ciências Agronômicas (FCA/UNESP), Rua José Barbosa de Barros, 1780, CEP 18610-307, Jardim Paraíso,Botucatu/SP, Brasil.. e-mail:jose.coelho@unesp.br
 5Prof. Dr. Depto de Solos e Recursos Ambientais, Faculdade de Ciências Agronômicas (FCA/UNESP), Rua José Barbosa de Barros, 1780, CEP 18610-307, Jardim Paraíso, Botucatu/SP, Brasil. e-mail: helio.grassi@unesp.br 
 
 
 1 RESUMO
 
 Objetivou-se avaliar o efeito do uso contínuo de doses de biossólido e efluente doméstico tratado no potencial de risco de sodicidade e salinidade do solo. O delineamento experimental foi inteiramente casualizado em parcelas subdivididas com dez tratamentos e cinco repetições. As parcelas consistiram no uso de dois tipos de água para irrigação (AR- efluente doméstico tratado e AB- água de abastecimento) e as subparcelas pelas doses de biossólido (0, 50, 100, 150 e 200 %), nos anos de 2011 a 2016. Avaliaram-se a condutividade elétrica (CE), pH, Ca, Mg, Na, RAS e PST do solo. Conclui-se que o efeito da adubação mineral (0% - controle) com AB foi semelhante ao uso do efluente na CE do solo para o mesmo tratamento. Doses a partir de 127,4% e 113,2% de biossólido, respectivamente, junto a AR e AB diminuíram o teor de Na+ trocável do solo. Os resultados indicaram baixo risco de sodicidade e salinidade, após cinco anos de uso.
 
 Palavras-chave: condutividade elétrica, sódio, reuso
 
 
 ALVES, D.A.S, DE MELO, R. O., DE LIMA, J., COELHO, J.C., GRASSI FILHO, H
 TEMPORAL EFFECT OF CONTINUOUS USE OF BIOSOLID AND EFFLUENT TREATED IN THE SOIL SODICITY AND SALINITY
 
 
 2 ABSTRACT
 
 The objective of this study was to evaluate the effect of continuous use of sewage sludge and treated domestic effluent on the potential risk of soil sodicity and salinity. The experimental design was completely randomized in split plots with ten treatments and five replications. The plots consisted of the use of two types of irrigation water (treated domestic effluent AR and supply water AB) and the subplots by the biosolid doses (0, 50, 100, 150 and 200%) in the years 2012 to 2017. The electrical conductivity (EC), pH, Ca, Mg, Na, RAS and PST of the soil were evaluated. It was concluded that the effect of mineral fertilization (0% - control) with AB was similar to the effluent use in soil EC for the same treatment. Doses from 127.4% and 113.2% of biosolid, respectively, with RA and AB decreased the exchangeable Na content of the soil. Results indicated low risk of sodicity and salinity after five years of use.
 
 Keywords: electrical conductivity, sodium, reuse.

Water Quality of Underground Wells in Limoeiro do Norte, Brazilian Northeast

The objective of this work was to assess the physicochemical and microbiological characteristics, as well as the potential of salinization and sodification of groundwater wells in Limoeiro do Norte, Ceará states, Brazil. Six water wells were selected for the study, all of them used for irrigation and human consumption. The ionic classification was performed by Piper Diagram and the salinity risk using the U.S.S.L. (United States Salinity Laboratory) Diagram using Qualigraf software. Based on the average chemical element concentration (mmolc L-1) in the groundwater, the following quantification is obtained: Na+ > Ca2+ > Mg2+ > K+ for cations. For anions there was a change in the the wells, for the 1, 3 and 4 Cl- > HCO3- > SO42- > CO32- and wells 2, 5 and 6 HCO3- > Cl- > SO42- > CO32-. The wells 1, 2 and 3 have severe restrictions for use by SAR (sodium absorption ratio) and Na+ content. Water from wells 1, 3 and 5 were classified as sodium chloride, 2 and 6 were classified as sodium bicarbonate and well 4 as calcium magnesium sulfate. With the exception of well 6 classified as freshwater, all other wells were classified as brackish water. Groundwater samples fall in C3S1 or C3S2 category with high salinity and low or medium sodium hazard. With the exception of Na+, whose value was above the limit allowed, no well with groundwater was detected chemical hazard for human consumption. There was the detection of Total coliforms, but in well 5 the presence of Thermotolerant coliforms was detected.