Coastal Saline Areas Research Articles

Salinity Effects on Soil Structure and Hydraulic Properties: Implications for Pedotransfer Functions in Coastal Areas

Understanding the effects of salinity on soil structure and hydraulic properties is critical for addressing environmental challenges in coastal saline and sodic areas. In this study, soil samples were collected from a coastal region in eastern China to investigate how salinity affected the soil structure and hydraulic properties based on lab experiments. A comprehensive soil dataset was also compiled from the experimental results to develop a salinity-based pedotransfer function (PTF-S) tailored to the coastal environment. The results showed that salinity significantly altered the soil aggregate size distribution and hydraulic properties. Higher salinity promoted the formation of larger aggregates (0.25–2 mm), particularly in silty clay soil. Salinity positively correlated with the saturated hydraulic conductivity (Ks) in sandy loam soil, regardless of the cation type (Na⁺ or Ca2⁺). By comparison, Na+ increased the Ks of silty clay soil up to a certain threshold, while Ca2+ enhanced the Ks regardless of the soil texture. Increased salinity also reduced the soil water retention of sandy loam soil; however, Na+ increased the soil water retention of silty clay soil and Ca2+ had different effects depending on the suction levels. The newly developed PTF-S model, which included the electrical conductivity (EC) and cation exchange capacity (CEC), showed better predictions for the volumetric water content (R = 0.886 and RMSE = 0.057 cm3/cm3) and log Ks (R = 0.991 and RMSE = 0.073 mm/h) than the traditional model that excludes the salinity variables EC and CEC (PTF-N) (R = 0.839 and RMSE = 0.066 cm3/cm3 for the volumetric water content, and R = 0.966 and RMSE = 0.140 mm/h for the log Ks). This study highlights the importance of developing salinity-based PTFs for addressing soil salinization challenges.

Soil spatial heterogeneity created by river–sea interaction influences Tamarix chinensis root features in the Yellow River Delta

AbstractSalt‐tolerant Tamarix chinensis roots are crucial in preserving wetland soil and carbon sequestration, which is essential for wetland ecology. Soil‐water‐salt conditions influence the growth of these roots in coastal saline areas, but the specific factors and their effects remain unclear. Using principal component and partial least square–structural equation modelling (SEM) methods, we studied T. chinensis root features in six Yellow River delta communities. Results showed varied root features across locations, with larger roots further inland. Root growth negatively correlated with soil texture and salinity and positively with groundwater levels. Soil texture and salinity decreased with distance from the coast, while groundwater increased with distance from the Yellow River. This suggests that geographical location influences soil‐water‐salt conditions, impacting root characteristics. The principal component analysis–derived root feature index captured 56.7% of root feature variation. SEM revealed geographical locations indirectly influence root features, with the Yellow River's proximity primarily affecting them through groundwater and coastal distance influencing via soil sand content and salinity. The study underscores the importance of these findings for wetland conservation and ecology.

Phenotypic variation and yield performance of selected pumpkin varieties in coastal saline area of Bangladesh

Phenotypic variation and yield performance of selected pumpkin varieties in coastal saline area of Bangladesh

Germination and early seedling growth of a medicinal plant giant milkweed (Calotropis gigantea) under salinity stress

Giant milkweed (Calotropis gigantea L.) is a salinity and drought-resistant xerophyte that is widespread around the world and serves significant ecological and medicinal purposes. The research aimed to evaluate the influence of saline stress on germination characteristics and prompt growth attributes of seedlings of C. gigantea. Seeds were germinated under five salinity levels viz. 0, 6, 8, 10 and 12 dS m-1 and allowed to grow for 30 days for traits assessment. Germination percentage (GP), germination rate index (GRI), co-efficient of the velocity of germination (CVG), mean germination time (MGT), Timson germination index (TGI), shoot length (SL), root length (RL), seedling dry weight (SDW) and healthy seedling number at 30 days were found lower in the salt solution compared to the control condition. Mean germination time was expanded with the increment of salinity levels. TGI of C. gigantea sustained a significant positive linear regression with GP (r = 0.9881), GRI (r = 0.9923) and CVG (r = 0.7887) at P < 0.001, but MGT (r = 0.7855) at P = 0.005. The correlation coefficient among the germination traits revealed insignificant between RL and other germination traits (GP, CVG, MGT, and TGI) except GRI (r = 0.499*) and SL (r = 0.541*). It is recommended that, as an emerging medicinal and fiber resource plant, C. gigantea can be cultured productively in coastal saline areas. Int. J. Agril. Res. Innov. Tech. 14(1): 10-17, June 2024

The prospects of intercropping of brinjal (Solanum melongena L.) with other vegetables on sorjan system in vulnerable southern coastal saline and non-saline areas of Bangladesh

The demand for food in Bangladesh is increasing due to the increasing population. Land is the primary natural resource that affords habitat and sustenance for living beings. In Bangladesh, the coastal areas cover an area of 47,201 km2 or 32 % of the total land under 19 districts of Bangladesh. The coastal southern saline and non-saline areas are vulnerable to water logging conditions and farmers cannot grow any crops except dry season (rabi). However, in some areas, farmers are trying to use their indigenous technologies to combat natural disasters to ensure food security. For example, floating, sorjan or raised bed systems are potential and farmers are practicing in these areas. Among these techniques, the sorjan bed system is one of the potential techniques that is extensively used in southern Bangladesh, particularly water logging conditions to improve food security. To enhance the production and make land cultivation profitable, the experiments were carried out at the farmers’ fields under the sorjan system in consecutive two growing seasons. The sole crop was brinjal (cv. BARI Begun-12), BARI Lalshak-1 (cv. Red amaranth), BARI Dhania-1 (cv. Coriander leaf), Cauliflower (cv. Cold queen), Cabbage (cv. Equatoria) and Knol Khol were utilized as intercropping with brinjal. The treatments were i) Sole brinjal, ii) Brinjal + Red amaranth, iii) Brinjal + Coriander leaf, iv) Brinjal + Cauliflower, v) Brinjal + Cabbage, and vi) Brinjal +. 24-day-old seedlings of the BARI Begun-12 grown in a nursery bed were transferred to the plots where the seeds of Red amaranth and Coriander leaf were directly sown. However, the seedlings of Cauliflower, Cabbage, and Knol Khol were also transplanted to the field after one week of transplanting brinjal. The results exposed that sole crops had the highest results in terms of days to flowering, days to first fruit set, days to first harvesting, leaf area, fruit length, fruit breadth, single fruit weight, fruits plant−1, fruit yield, TSS %, and dry matter %. In both years, brinjal exhibited the highest yield as the sole crop compared to intercropping. 48.12 t/ha and 46.27 t/ha in the first and second cropping seasons, respectively. In the first cropping season, Red amaranth, Coriander leaf, Cauliflower, Cabbage, and Knol Khol performed with a yield of 10.12, 7.23, 23.14, 22.87, and 9.05 t/ha. During the second cropping season, the same crops exhibited a yield of 10.05, 7.01, 23.09, 22.68, and 9.98 t/ha. The highest land equivalent ratio, gross return, net return, and BCR were obtained from brinjal-cauliflower intercropping, which was 1.74, 1049300 BDT, 553820 BDT, and 2.12, respectively, in the 2021–2022 cropping season and 1.78, 1057900 BDT, 562010 BDT, and 2.13, respectively, in the next season in 2022–2023. This intercropping approach resulted in a higher land equivalent ratio, net return, and benefit-cost ratio of 1.76, 557915 BDT, and 2.125, respectively, over the average of two successive cropping seasons.

Differential Responses of Bacterial Communities in Rhizosphere and Bulk Soils of Cotton to Long-Term Amelioration Practices Based on Freezing Saline Water Irrigation and Plastic Mulching in a Coastal Saline Soil

Soil amelioration in coastal saline areas plays an important role in alleviating land resource shortages, improving regional ecological environments, ensuring food security, and promoting economic development. Plastic mulching (M) and the combination of freezing saline water irrigation and plastic mulching (WIM) are successful amelioration practices that dramatically reduce the salinity of surface soil and facilitate plant growth in coastal saline soil. However, the bacterial responses that are closely related to these amelioration practices in coastal saline soil remain poorly understood. In this study, bacterial richness and diversity, community composition, and potential ecological functions in the rhizosphere and bulk soils of cotton in M and WIM treatments, along with a control treatment, were investigated using high-throughput sequencing in a coastal saline field. The results showed that both the M and WIM treatments increased bacterial richness and alpha diversity, which were in general significantly higher in bulk soil than in rhizosphere soil. Non-metric multidimensional scaling and the Bray–Curtis dissimilarity analysis revealed that the bacterial community in rhizosphere soil was assembled far from those in the control and bulk soils and behaved more specifically in rhizosphere soil than in bulk soil. The relative abundances of most of the dominant phyla showed opposite trends of variation in bulk and rhizosphere soils compared to those in control soil in both M and WIM treatments; in particular, the specific bacterial groups of Proteobacteria and Actinobacteria decreased in bulk soil but significantly increased in rhizosphere soil. Functional groups of chemoheterotrophy, aerobic chemoheterotrophy, and nitrate reduction were predominant in rhizosphere rather than bulk soil, according to the Functional Annotation of Prokaryotic Taxa. These findings improve the understanding of the mechanism of bacterial responses to amelioration practices M and WIM in coastal saline soils and provide valuable information for the development of amelioration techniques based on agricultural practices and soil microbiome to enhance plants’ adaptability to saline soil in the future.

Promotion effects of salt-alkali on ammonia volatilization in a coastal soil

Coastal ecosystems are highly susceptible to salt-related problems due to their formation process and geographical location. As such ecosystems are the most accessible land resources on Earth, clarifying and quantifying the effects of salt-alkali conditions on N concentration and ammonia (NH3) volatilization are pivotal for promoting coastal agricultural productivity. The challenge in establishing this effect is to determine how salt-alkali conditions impact NH3 volatilization through direct or indirect interactions. An incubation experiment using a coastal soil from a paddy farmland, combined with the structural equation modeling (SEM) method, was conducted to reveal the net effects of salt-alkali on NH3 volatilization and the role of environmental and microbial factors in mutual interaction networks. The specific experimental design consisted of four salt treatments (S1, S2, S3, and S4: 1‰, 3‰, 8‰, and 15‰ NaCl by mass of soil, respectively), four alkaline treatments (A1, A2, A3, and A4: 0.5‰, 1‰, 3‰, and 8‰ NaHCO3 by mass of soil, respectively) and a control without NaCl or NaHCO3 addition (CK), and each treatment had three urea concentrations (N1, N2, and N3: 0.05, 0.10, and 0.15 g N kg-1 soil, respectively) and three replicates. At the N1, N2, and N3 levels, NH3 volatilization increased by 9.31%–34.98%, 3.07%–26.92%, and 2.99%–43.61% as the NaCl concentration increased from 1‰ to 15‰, respectively, compared with CK. With an increase in the NaHCO3 concentration from 0.5‰ to 8‰, NH3 volatilization increased by 8.36%–56.46%, 5.49%–30.10%, and 30.72%–73.18% at the N1, N2, and N3 levels, respectively, compared with CK. According to the SEM method, salinity and alkalinity had positive direct effects on NH3 volatilization, with standardized path coefficients of 0.40 and 0.19, respectively. Considering the total effects (net positive and negative effects) in the SEM results, alkalinity had a greater influence than salinity (total standardized coefficient 0.104 > 0.086). Nitrogen concentrations in the incubation system showed a direct positive effect on NH3 volatilization (standardized path coefficient = 0.78), with an obvious decrease under elevated salinity and alkalinity levels. Additionally, gene abundances of nitrogen-transforming microbes indirectly increased NH3 volatilization (total indirect standardized coefficient = 0.31). Our results indicated that potential NH3 emissions from coastal saline areas could be enhanced more by soil alkalization than by salinization.

Effects of gibberellic acid, kinetin and indole butyric acid mixture on sorghum salinity tolerance and grain yield in saline-alkali coastal zone.

The development and utilization of coastal saline-alkali lands hold significant importance in mitigating the shortage of cultivated land resources in China, enhancing the agro-ecological environment in coastal saline and alkaline areas, and ensuring national food security. We set up both pot and field trials (randomized block design) at Xinxiang experimental station of Institute of Crop Science, Chinese Academy of Agricultural Sciences (ICS-CAAS) and Dongying Yellow River Delta Modern Agricultural Research Base in Shandong Province in 2021 and 2022, respectively. The experimental materials, Jiliang 1 and Jiliang 2, underwent seed dressing with GKI composites at concentrations of 2.5 and 5 mL·kg-1. These composites, which contained the main components of gibberellin, kinetin, and indole butyric acid, were denoted as GKI2.5 and GKI5.0, respectively. The control plots (CK) received water seed dressing. The aim was to assess the regulatory effects of GKI on salt tolerance and grain sorghum yield. Compared to CK, the GKI2.5 and GKI5.0 seed dressing treatments significantly enhanced the growth and development of the two grain sorghum varieties, increased antioxidant enzyme activity and soluble protein content of sorghum leaves, while reducing leaf malondialdehyde content. Moreover, the GKI treatments increased leaf net photosynthetic rate. Under field conditions, yields of Jiliang 1 and Jiliang 2 were enhanced by an average of 17.1% and 19.1%, respectively. In conclusion, GKI seed dressing treatment effectively promoted the growth and development of sorghum under salt stress. It enhanced the antioxidant and osmoregulatory capacities of leaves, reduced the level of membrane lipid peroxidation, and improved net photosynthetic rate of leaves, which together improved the salt tolerance and sorghum yield.

Using a mixed layered soil model to optimize the layout of coastal direct current (DC) grounding electrodes

Abstract In recent years, with the rapid development of the coastal economy and the large-scale development of marine resources, power demand has risen sharply. So it is urgent to promote the construction of UHVDC projects. Coastal saline areas often contain more chloride and other salts than other inland areas due to the high humidity, salinity and light intensity of the marine climatic and environmental conditions, which lead to the different electrical performance of grounding electrodes under different layouts. Therefore, one of the key issues to realizing the rapid development of UHVDC in coastal countries is how to choose the best layout of the coastal DC grounding electrode. It is intended to simulate the coastal environment and establish a mixed stratified soil model using CDEGS to verify the validity of the model through experiments in this paper. Based on the mixed soil model, the changes in grounding resistance, surface potentials and step voltage of grounding electrode sites under zigzag shape, two-row and circular shapes layouts are studied. The results show that when the zigzag shape layout is selected, the ground potential amplitude of the grounding electrode is reduced by 45.77% and 42.7%, the step voltage amplitude is decreased by 39.85% and 32.22%, and the grounding resistance is decreased by 28.45% and 27.68%, compared with the two-row and circular layout. In addition, its utilization rate of electrodes is better than the other two layout shapes.

Sowing date-induced salinity stress impacts the performance of mustard genotypes grown in the coastal saline areas of Bangladesh

Sowing date-induced salinity stress impacts the performance of mustard genotypes grown in the coastal saline areas of Bangladesh

Cultivation of red cabbage in Coastal Shyamnagar and Kaligonj upazilla subsumed by Nowabenki Gonomukhi Foundation

NGF working to disseminate new technology and new crop in the coastal saline area. Farmer generally get Aman rice then field become highly saline but using new climatic resilient technique farmer can cultivate Rabi crop in the specific area. For increasing production and cropping pattern it is crying need to introduce new high valued, short durational crop to this area. As a result NGF demonstrate different new crop in the farmer field. Farmer adopt Red Cabbage as high valued crop.

Rice-based Cropping System Intensification in the Coastal Saline area of Bangladesh: Problems and Prospects

The coastal zone environment of Bangladesh is characterised geographically by river deltas and estuaries, where tidal and riverine flooding and varying salinity levels affect agriculture and livelihoods. In this area, the land and agricultural productivity is very low because of several constraints, particularly waterlogging, high salinity of soil and water, freshwater scarcity for crop irrigation and natural disaster. In this review, the objectives are to focus on the limiting factors for crop intensifying and highlighting the opportunities to increase coastal agriculture while enhancing farmer’s livelihoods. Some recent studies demonstrated many opportunities for increasing cropping systems that have not yet been exploited extensively. Rainwater or low saline river water storing in the internal canal can fulfil the water requirement for dry season rice and non-rice crops, thereby increasing growth and yield. Early establishment of “Rabi” crops (non-rice) can utilize maximum low-saline soil water and escape high salinity/drought or heat/storms at later period of the growing stages, but this early sown Rabi crops needs early harvest of Aman rice around 15-30 days earlier than farmer practices. Moreover, early sowing by zero tilled dibbling (such as sunflower, maize, wheat, and potato) in wet soils results in higher yield potential. Using rice straw mulch ~5 t ha-1 has been shown to be highly beneficial for ameliorating soil constraints. A recent study revealed that straw mulch application on soil surface increased soil water and soil solute potential in the upper root zone, reduced soil salinity, soil strength, and cracking which attributed to higher yield. Considering the successful dry season crop establishment and yield potential requires early drainage to remove excess soil water and a drainage system that mitigates waterlogging from heavy rainfall events during the growing season. We expect this review will facilitate the future research planning and execution in this vulnerable coastal environment. Bangladesh Rice J. 25 (2) : 31-43, 2021

Evaluation of Salinity-Tolerant Backcrossed Inbre Lines (BILs) For Fertility Restoration Using Molecula Markers

Fertility restoration is a very important trait for the WA-CMS system in hybrid rice. Fifty-five BILs derived from KMR3 and FL478 cross combination possessing Saltol1 generated through Marker Assisted Backcross Breeding (MABB) approach were screened using Rf4 and Rf3 markers during Rabi 2021. The use of molecular markers tightly linked with fertility restoration aided in identifying promising groups of restorers, maintainers, partial restorers, and partial maintainers. The presence of both Rf4 and Rf3 alleles among the nineteen BILs was 35% which showed a clear difference in the marker distribution among the BILs. The BILs namely TCP32, TCP34, TCP35, TCP36, TCP36-3, TCP37-2, TCP38, TCP13, TCP18, TCP19, TCP45, TCP46, TCP48, TCP54, TCP56, TCP57-1, TCP60, TCP61, TCP61-3 were identified as promising restorers possessing both Rf4 and Rf3 genes. The current study reflects that Rf4 and Rf3 genes in combination help in the breeding of WA-CMS-based hybrids in Saltol introgressed restorers with better heterosis under various ecologies, especially coastal saline areas.

Optimizing Phosphorus Application for Winter Wheat Production in the Coastal Saline Area

Phosphorous (P) fixation in saline soils is a concern worldwide. To investigate optimization strategies for P fertilizer application that improve P use efficiency (PUE) and crop yield in saline soil, in terms of P sources and rates, we conducted a two year field experiment in the coastal saline area of China to investigate the effects of P rates and sources, including superphosphate (SSP), monoammonium phosphate (MAP) and ammonium polyphosphate (APP) on yield, aboveground P uptake, agronomy efficiency (AEP), and soil available P of winter wheat (Triticum aestivum L.). Wheat yield, under the three P sources, increased with P rates and reached a plateau under 20 kg P ha−1 SSP,18 kg P ha−1 MAP, and 17 kg P ha−1 MAP, respectively. The application of SSP increased the wheat yield by 9–11% compared to MAP and APP. The aboveground P uptake of winter wheat under SSP was 14% and 13% higher than MAP and APP, respectively, under the optimal P application rate. The AEP under SSP was higher than the other two P sources under the same P rate. SSP increased the soil Ca2+ concentration by 20–42%, but decreased the Na+ concentration by 14–18% at the P rate of 26 kg P ha−1 in all soil layers, including 0–20, 20–40, 40–60 cm, compared to CK (0 kg P ha−1). The soil Olsen-P concentration under APP was higher than the other P sources. This study suggests that optimizing P sources and rates can improve wheat yield, PUE, and soil quality in the coastal saline soil.

Response of Rice Yield and Grain Quality to Combined Nitrogen Application Rate and Planting Density in Saline Area

To determine the combining effects of nitrogen application rate and planting density on rice yield and grain quality formation under salinity conditions, a field experiment was conducted in the coastal saline area using Oryza sativa L. cv. Nangeng 9108 from 2019 to 2020. The experiment was designed with six nitrogen rates (0, 210, 255, 300, 345, and 390 kg ha−1; denoted as N0-N390, respectively) and two transplanting densities (334,000 and 278,000 hills ha−1; denoted as D1 and D2, respectively). The results indicated that, with the increase of nitrogen input rate, the panicles number and spikelets per panicle increased first, subsequently decreased, and peaked under 300 kg ha−1 N, whereas the filled-kernel rate and grain weight displayed a decreasing trend. The panicle number and grain weight were higher under D1 treatment compared to those under D2 treatment, while the spikelet number per panicle and the filled-kernel rate displayed an opposite trend. The grain yield displayed highest under N300D1 treatment among all treatments, accompanied by the highest agronomic N use efficiency, and the actual yield reached 8060.4 kg ha−1 and 7869.8 kg ha−1 in 2019 and 2020, respectively. Increased nitrogen application rate significantly improved the grain processing quality and nutritional quality, while reducing the appearance quality and cooking/eating quality. Higher transplant density was conductive to grain nutritional quality, but notably reduced the processing quality, appearance quality and cooking/eating quality. Overall, a combination of 300 kg ha−1 nitrogen rate and 334,000 hills ha−1 planting density was recommended for relatively higher rice yield and better grain quality in the saline area.

Assessment and prediction of coastal saline soil improvement effects combining substrate amendments and salt barrier materials in typical region of the Yangtze River Delta

Coastal saline regions are characterized by high salinity, low permeability, organic matter deficiency, shallow groundwater depth, which limit leaching and lead to salt return. However, there remains a lack of targeted research on long-term coastal saline soil improvement by combining permeation promotion and salt return suppression. Based on a case study of the coastal saline area of Jiangsu Province, China, we used dynamic monitoring of soil water and salt transport, along with laboratory and field scale experiments to analyze the effect of combining substrate amendments and salt barrier materials on salt leaching and return. And numerical simulations were used to predicted the effects of the optimized combination improvement schemes under different climatic conditions in the future. The 2–4% (w/w) straw amended soil had a greater increase (＞90%) in desalinization ratio and a higher reduction (more than half) in desalination time due to changes in soil physical properties. The geocomposite isolated salt effectively due to the formation of capillary barrier compared with traditional straw burial. The results of field scale experiments and numerical simulations showed that geocomposite salt barrier material combined with straw substrate amendment scheme provides a cost-effective solution of soil salinization in coastal areas.

Heterografted chrysanthemums enhance salt stress tolerance by integrating reactive oxygen species, soluble sugar, and proline.

Chrysanthemum, one of the most important commercial ornamental crops, is susceptible to salinity, which limits its cultivation and application in coastal and inland saline areas. Grafting is widely used to improve the salt tolerance of horticultural crops, but the mechanisms of grafted chrysanthemum responses to salt stress remain unclear. In this study, we showed that heterografted chrysanthemums with Artemisia annua as rootstock exhibited increased salt tolerance compared with self-grafted and self-rooted chrysanthemums. Under high salt stress, the roots of heterografted chrysanthemums enrich Na+, resulting in a reduction of Na+ toxicity in the scion, with only a small amount of Na+ being transported to the leaves. On the other hand, the roots of heterografted chrysanthemums alleviated high Na+ stress via enhanced catalase enzyme activity, downregulation of the expression of reactive oxygen species (ROS) accumulation-related genes, massive accumulation of soluble sugars and proline, and upregulation of the expression of heat shock protein-related genes to enhance salt tolerance. In addition, the leaves of heterografted chrysanthemums respond to low Na+ stress by increasing peroxidase enzyme activity and soluble sugar and proline contents, to maintain a healthy state. However, self-grafted and self-rooted plants could not integrate ROS, soluble sugars, and proline in response to salt stress, and thus exhibited a salt-sensitive phenotype. Our research reveals the mechanisms underlying the increased salt tolerance of heterografted chrysanthemums and makes it possible to have large-scale cultivation of chrysanthemums in saline areas.

Soil fertility, chemical properties, and pollutant removal efficiency of Salicornia europaea in response to differenttimes and duration ofwastewater irrigation.

Halophytes are the good candidates in coastal saline areas which could be irrigated with wastewater. The purpose of this study was to evaluate the soil-water-plant system under control and wastewater irrigation (containing toxic elements and organic matter) at three durations (vegetative, flowering, and reproductive stages) and two exposure times (2 and 4 days in each stage). The results obtained in the experimental tests for wastewater irrigation indicated that the Salicornia is efficient for the removal of chemical oxygen demand (61%), biochemical oxygen demand (74%), total suspended solids (47.6%), and ammoniacal nitrogen (64%) at the reproductive stage. At the same time, the average nitrate concentration increased to 51.3mg L-1 with more solids. Regardless of wastewater irrigation duration, irrigation with wastewater significantly increased organic matter, nitrogen, phosphorus, and potassium of the soil. The Mg2+ and Ca2+ contents in the aboveground biomass of the plants were also high ranged from 0.58 to 1%, and 0.43 to 0.68mgg-1 DW, respectively. All the exchangeable cations other than Na+ were higher for wastewater irrigation at the flowering stage. Plants maintained noticeably higher Ca2+/Na+ and K+/Na+ ratios in the roots than those in the shoots except for 4 days after the reproductive stage. S. europaea is well adapted to grow in wastewater irrigation and can tolerate hypoxic conditions through improving water and soil quality.

The Salicornia europaea potential for phytoremediation of heavy metals in the soils under different times of wastewater irrigation in northwestern Iran.

The use of wastewater for irrigation usually leads to the buildup of potentially toxic elements (PTEs) in soils. The objective of this study was to assess the capacity of Salicornia europaea L. to uptake heavy metal when irrigated with wastewater at the vegetative, flowering, and reproductive stages of S. europaea for 2 and 4 days (in each stage) in the coastal saline area of Lake Urmia. The concentrations of heavy metals were detected in irrigated water, soil, and plant samples, while transfer factor (TF), bioconcentration factor (BCF), and bioaccumulation factor (BAF) were calculated. The results revealed that metal concentrations in the wastewater were above the permissible limits. The wastewater irrigation caused higher shoot biomass despite the high uptake of PTEs. Levels of Fe and Cu in plants were higher when irrigated with wastewater at the reproductive stage as compared to flowering and vegetative stages. The TF of wastewater-irrigated plants was higher at the flowering stage. TF of different metals at the flowering stage were in order of Zn > Pb > Ni > Cd > Cu, while the BCF increased in the order Cd > Cu > Zn > Ni > Pb. The BAF of the investigated PTEs at the flowering stage increased in the order Cd > Pb > Ni > Zn > Cu. In conclusion, higher Pb and Zn in the shoot indicated that the plant exhibited the phytoextraction mechanism, while Salicornia used a phytostabilization mechanism for roots-Cu, Ni, and Cd.

Integrated nitrogen amount and sources maximize maize nitrogen efficiency in the saline soils

AbstractAlthough efficient N fertilization has become widely accepted for sustaining or improving N use efficiency (NUE), many existing N fertilizer recommendations seldom consider N sources during implementation. To investigate the effect of N rates and sources on maize (Zea mays L.) production efficiency, soil quality, and economic benefits, a field experiment was conducted in the coastal saline area of China. The optimal N rate (ONR) treatment based on in‐season root‐zone N management reduced N application amount by 44% without grain yield losses and decreased the apparent N losses by 144 kg N ha–1 compared with the local N management practice of farmers. Furthermore, the ONR treatment with ammonium sulfate (ONR‐AS) or calcium ammonium nitrate (ONR‐CAN) had higher maize grain yield and NUE than the ONR with urea (ONR‐urea) treatment. Compared with ONR‐urea, treatment with ONR‐AS or ONR‐CAN increased Ca2+ content, decreased soil pH and Na+ content, and thus imporved maize yield and NUE. Among the ONR treatments, the ONR‐AS treatment increased economic gains compared with the ONR‐urea treatment. This study suggests that an integrated N management can increase maize yield, NUE, and economic benefits and improve soil quality in the coastal saline soils.