Soil Salinity Levels Research Articles

Recovery of a salinized tomato field in a coastal polder after the 2016 Kumamoto Earthquake in Japan

After the 2016 Kumamoto Earthquake (Kumamoto earthquake sequence) of maximum magnitude M7.3 occurred, agricultural fields and crops were significantly damaged by soil liquefaction in lowland polders, which had shallow saline groundwater. A desalinization treatment was required to recover agricultural production in polders in Kumamoto. To understand the soil salinity levels in the root zone, we installed multiple-point measurements using the wireless sensor network system (WSNS) for real-time monitoring of soil moisture (θ ) and bulk soil EC (ECb) in a cherry tomato greenhouse. Pore-water electrical conductivity (ECw) can be estimated as an indicator of the field's salinity level simultaneously. First, we found rapid increases in θ and ECw where soil liquefaction and sand boils occurred. Through soil survey, we confirmed the existence of a large channel beneath one of the liquefaction plots, suggesting considerably high spatial heterogeneity of soil salinity across the greenhouse. Secondly, the high salinity level could not be controlled by drip irrigation at all. Finally, 1-week flooded leaching treatments were carried out; the electrical resistivity tomography (ERT) survey indicated that the salinity level decreased significantly except around the channel plot. The combination of the flooded leaching and natural rainfall was more effective for salt leaching in macropores and channels. Our analysis using the WSNS highlighted three management strategies that may help reduce a polder's salinity level.

Predicting Dynamics of Soil Salinity and Sodicity Using Remote Sensing Techniques: A Landscape-Scale Assessment in the Northeastern Egypt

Traditional mapping of salt affected soils (SAS) is very costly and cannot precisely depict the space–time dynamics of soil salts over landscapes. Therefore, we tested the capacity of Landsat 8 Operational Land Imager (OLI) data to retrieve soil salinity and sodicity during the wet and dry seasons in an arid landscape. Seventy geo-referenced soil samples (0–30 cm) were collected during March (wet period) and September to be analyzed for pH, electrical conductivity (EC), and exchangeable sodium percentage (ESP). Using 70% of soil and band reflectance data, stepwise linear regression models were constructed to estimate soil pH, EC, and ESP. The models were validated using the remaining 30% in terms of the determination coefficient (R2) and residual prediction deviation (RPD). Results revealed the weak variability of soil pH, while EC and ESP had large variabilities. The three indicators (pH, EC, and ESP) increased from the wet to dry period. During the two seasons, the OLI bands had weak associations with soil pH, while the near-infrared (NIR) band could effectively discriminate soil salinity and sodicity levels. The EC and ESP predictive models in the wet period were developed with the NIR band, achieving adequate outcomes (an R2 of 0.65 and 0.61 and an RPD of 1.44 and 1.43, respectively). In the dry period, the best-fitted models were constructed with deep blue and NIR bands, yielding an R2 of 0.59 and 0.60 and an RPD of 1.49 and 1.50, respectively. The SAS covered 50% of the study area during the wet period, of which 14 and 36% were saline and saline-sodic soils, respectively. The extent increased up to 59% during the dry period, including saline soils (12%) and saline-sodic soils (47%). Our findings would facilitate precise, rapid, and cost-effective monitoring of soil salinity and sodicity over large areas.

Neem and Castor Oil–Coated Urea Mitigates Salinity Effects in Wheat by Improving Physiological Responses and Plant Homeostasis

Soil salinity is abiotic stress of growing concern, whose effects can be potentially mitigated by the use of suitable fertilisers. Based on this, an experiment was conducted to determine the role of vegetable oil–coated urea on the performance of wheat (Triticum aestivum) under salinity. Neem oil–coated urea (NOCU), castor oil–coated urea (COCU), and normal urea (NU) were compared in wheat plants growing in pots at three soil salinity levels (0, 6, and 12 dS m-1). Plant morphology, growth, element contents (Na, Cl, K, and N), and several traits were assessed at the flag leaf stage; biological yield, grain yield, and its components were assessed at maturity. Salinity stunted growth (approximately -50% yield with high salinity vs. control); boosted Na and Cl concentrations while abating K and N concentrations in plant organs; impaired leaf water status; reduced photosynthetic pigments and increased antioxidant activities and osmo-regulating compounds. NOCU and, to a lesser degree, COCU mitigated salinity effects by upgrading antioxidant activities, reducing oxidative stress markers, increasing leaf water status, photosynthetic pigments, and osmo-regulating compounds. However, NOCU under high salinity could only achieve the levels of NU under intermediate salinity. Lastly, NOCU and COCU restricted plant entry of adverse ions (Na and Cl) while increasing K and N accumulation. Vegetable oil–coated urea, namely NOCU, significantly contributed to improving wheat behaviour and final yield under salinity. These outcomes are associated with the two fertilisers’ properties of slow nitrogen release.

Amendment of Saline–Alkaline Soil with Flue-Gas Desulfurization Gypsum in the Yinchuan Plain, Northwest China

The effective and safe use of FGD gypsum in agricultural land is still debated in some countries even though its effectiveness in soil management has been reported in many studies. Thus, the changes in the levels of soil salinity, alkalinity, crop yield, and other physicochemical properties in different soil types and crops after reclamation and planting with FGD gypsum over four years are evaluated in this paper. The main aim of this paper is to review the effects of six treatment technologies in addressing soil salinity and sodicity and crop production in soils, with a focus on the basic theory, key technologies, and industrialized applications. This paper also shows that soil conditions can be improved and crop yields can be increased by using FGD alone or in combination with humic acid or fertilizer. FGD gypsum plus K–Zn–Mn fertilizer increased the yield of rice by 135%. In alkaline, salinized, and secondary salinized soils, FGD gypsum combined with organic fertilizer or organic plus chemical fertilizer increased the yield of rice by 21.2% and 60.4%, the yield of sunflower by 2.4% and 23.6%, and the yield of medlar by 18.81% and 20.78%, respectively. The application of FGD gypsum also increased the salt tolerance of salt-tolerant plants. Combined with drainage, laser field levelling and tillage decreased soil salinity by more than 63.76% and increased the yield of oil sunflower by up to 96.96%. This study provides convincing evidence of the benefits of the application of the six treatments to reclaim saline–alkali soils. It is suggested that comprehensive measures should be taken to improve saline–alkaline soil.

Modeling impacts of saltwater intrusion on methane and nitrous oxide emissions in tidal forested wetlands.

Emissions of methane (CH4 ) and nitrous oxide (N2 O) from soils to the atmosphere can offset the benefits of carbon sequestration for climate change mitigation. While past study has suggested that both CH4 and N2 O emissions from tidal freshwater forested wetlands (TFFW) are generally low, the impacts of coastal droughts and drought-induced saltwater intrusion on CH4 and N2 O emissions remain unclear. In this study, a process-driven biogeochemistry model, Tidal Freshwater Wetland DeNitrification-DeComposition (TFW-DNDC), was applied to examine the responses of CH4 and N2 O emissions to episodic drought-induced saltwater intrusion in TFFW along the Waccamaw River and Savannah River, USA. These sites encompass landscape gradients of both surface and porewater salinity as influenced by Atlantic Ocean tides superimposed on periodic droughts. Surprisingly, CH4 and N2 O emission responsiveness to coastal droughts and drought-induced saltwater intrusion varied greatly between river systems and among local geomorphologic settings. This reflected the complexity of wetland CH4 and N2 O emissions and suggests that simple linkages to salinity may not always be relevant, as non-linear relationships dominated our simulations. Along the Savannah River, N2 O emissions in the moderate-oligohaline tidal forest site tended to increase dramatically under the drought condition, while CH4 emission decreased. For the Waccamaw River, emissions of both CH4 and N2 O in the moderate-oligohaline tidal forest site tended to decrease under the drought condition, but the capacity of the moderate-oligohaline tidal forest to serve as a carbon sink was substantially reduced due to significant declines in net primary productivity and soil organic carbon sequestration rates as salinity killed the dominant freshwater vegetation. These changes in fluxes of CH4 and N2 O reflect crucial synergistic effects of soil salinity and water level on C and N dynamics in TFFW due to drought-induced seawater intrusion.

Performance Evaluation of Food Barley (<i>Hordeum vulgare L.</i>) Varieties for Grain Yield and Other Agronomic Traits in Buno Bedele, South West Oromia, Ethiopia

Barley is a major cereal crop in Ethiopia accounting for about 20% of the total cereal production. It is grown in a wide range of agro-climatic regions under several production systems. Barley grows best on well drained soils and can tolerate higher levels of soil salinity than most other crops. Although many improved food barley varieties have been released nationally and regionally, these varieties have not been tested in Buno Bedele and subsequently are not well popularized as well. In this Zone, farmers are growing local varieties which are low yielder and susceptible to diseases and other stresses. Hence recently released food barley varieties were tested for their phenotypic performance to confirm their environmental adaptation using Randomized Complete Block Design in three replications for two consecutive years (2020 to 2021) in Gechi and Chora districts. Quantitative traits such as plant height, spike length, Biomass, and grain yield were collected and analyzed using RStudio and Genstat 18^th edition software’s. Qualitative trait such as days to maturity and days to heading were also collected. The combined analysis of variance indicated that the eight tested varieties showed significant variations for all traits. The highest combined mean grain yield was recorded from variety “Adoshe” (5184 kg ha^-1) followed by “HB 1966” (4758 kg ha^-1).

Appropriateness of Land and Crop Selection for an Area in Iraq Al-Salamiyat

Al-Salamiyat project, which is situated inside the administrative boundaries of Baghdad Governorate and has a total size estimated at 2621 hectares, required a study to assess the lands for cereal crops (wheat, barley, and maize). The study region was visited and examined repeatedly in order to set up and gather data; take soil models; observe the land cover; the level of soil salinity; the kind of agricultural use; and the planted crops. The internodes project was covered by satellite imagery retrieved from the satellite sentinel (2B) Al-Mashhad (SMC) for the month of March 2021. The soil model’s physical and chemical characteristics were estimated. The analyses’ findings demonstrated that the research area’s soils had a degree of interaction (PH), as estimated values for this characteristic ranged from 7.05 for soil model No. 8 to 7.9 for model No. 11, or neutral to medium basal. Because most of the study area’s lands are used for agriculture and have a high percentage of vegetative cover, the majority of the soils there contain modest amounts to moderately moderate salt. Carbonate minerals factor: According to Sys et alsuggestions.’s from 1993, the carbonate minerals factor estimations for wheat and barley harvests were 95% for all soils of the study area, and the final estimates for maize yield ranged from 60% to 85%. According to the findings, the estimations of the amount of exchanged sodium in the study area’s soils were a non-specific factor for the growth of the chosen crops and were given an estimate higher than 95%.. The evaluation of the soil’s properties for the research area’s specified crops showed that the (S1) variety is extremely suited for growing wheat, barley, and yellow corn due to the absence of determinants, while the (S2) class is moderate and acceptable for growing wheat and maize due to high salinity.

Performances of black seed sesame (Sesamum indicum L.) under low fertility saline soils

The world need for healthy cooking oil has readjusted research into other non-conventional oil crops like sesame. The importance of sesame is not only because of its healthy oil crop but also because of its short life cycle making it an attractive cash crop. The crop has been reported to be moderately sensitive to saline-soil and drought. Previous reports on the salinity tolerance were conducted on artificial saline soils with considering fertility thus it is important to evaluate the crops performance on naturally low fertility saline soils. Therefore, the objective of this study was to investigate the effect of saline-soil on growth, development and yield and yield related traits of black seed sesame. The pot experiment was conducted at Buri Ram province Thailand, in a 2 × 6 factorial in RCBD with three replications, where factor A was the soil salinity levels and factor B was the sesame cultivars. Sesame seeds were planted in a seedbed and later were transplanted into the 72 experimental pots each filled with 9 kg soil. Observed results showed that salinity levels had effect on sesame i.e. plant height, number of branches at 30 DAT, SCMR, total chlorophyll content, number of capsules, total dry weight and capsules dry weight. An interaction between salinity level and cultivar was also investigated i.e. number of branches and capsules, total and capsules dry weight and harvest index (HI). Salinity levels had influence on sesame both on growth and yield parameters; cv. Kanchanaburi and KKU2 showed higher number of capsules when compared with other cultivars grown under saline soil, whereas cv. Kanchanburi, UB3 and Buriram gave higher capsules dry weight under saline-soil.

Foliar Application of Liquid-Silicate Rock Fertilizer Counteracts the Suppressing Effects of Saline Soils on Soybeans: A Glasshouse Assessment

Developing an alternative method for productive farming on saline soils is necessary because remediating the soils is not feasible on-farm. A foliar application of liquid-silicate rock fertilizer (LSRF) was proposed in response to this need, and its effectiveness was evaluated in a greenhouse. The specific aim of the research was to identify the effects of LSRF on the growth and yield components of soybeans grown on salinized soils. The experiment employed a split plot in a completely randomized design, with the main plot consisting of soil salinity levels (EC), i.e., 0.5, 1.5, and 2.5 dS. m-1 and the sub-plot was the concentration of applied LSRF, i.e., 0, 1, 2, and 3 %, in triplicates. Results reveal an increase in soil EC to 2.5 dS. m-1 slowed down the growth rate and reduced the yield of soybeans by about 20 %. In contrast, applying LSRF at concentrations ranging from 1 to 3% improved soybean growth and yield components while reducing the severity of soil salinity’s effects on the plant. Foliar application of LSRF could be an effective method of reducing the stresses caused by saline environments in soybeans. How to Cite: Joko Priyono, Akhmad Zubaidi, 2023. "Foliar Application of Liquid-Silicate Rock Fertilizer Counteracts the Suppressing Effects of Saline Soils on Soybeans: A Glasshouse Assessment." Journal of Agriculture and Crops, vol. 9, pp. 250-256.

Root, Yield, and Quality of Alfalfa Affected by Soil Salinity in Northwest China

Growing crops in salt-affected soils has become increasingly important for sustainable development in arid and semi-arid regions. Knowledge on the responses of alfalfa root development, yield, and quality to soil salinity is critical for assessing the productivity and profitability of salt-affected soils. A field experiment with a total of six treatments combining three soil salinity levels and two biosolids fertilizer levels was conducted in 2018 and 2019 in northwest China. For salinity treatments, the salt addition rates were 2‰, 4‰, and 6‰ of 0–60 cm soil dry weight, while a commercial biosolids fertilizer was added at a rate of 0 and 1.5 Mg·ha−1 of 0–10 cm soil for biosolids treatment. Root parameters of root length (RL), surface area (RSA), diameter (RD), volume (RV), and dry matter (RDM) were obtained at the end of each year, while yield and quality parameters of crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF) were measured for each cut of the two years. Most root parameters were significantly reduced by the highest soil salinity treatment in 2018, but not affected by salinity in 2019. Higher salinity treatments consistently led to lower plant height and yield, higher CP, and lower ADF and NDF in both years. The absolute slope value of the regression between yield of each cut with the respective soil salt content was smaller for the later cuts. The relationship between plant height and quality parameters varied depending on soil salinity levels and between the two years, and plant height was found to be a good predictor for alfalfa quality in 2019. Biosolids fertilizer had no significant effect on any alfalfa root, growth, or quality parameters. The results are expected to assist determining the proper soil salinity range, maximizing the productivity that takes both yield and quality into consideration.

METHOD OF IDENTIFYING HAZARDS AND PREDICTING THE EMERGENCY SITUATIONS IN CASE OF SOIL CONTAMINATION BY HEAVY METAL COMPOUNDS

Purpose. The goal of the article is to develop a method for identifying hazards and predicting the possibility of a technogenic emergency caused by the spread of compounds with heavy metals in the soil during long-term storage of galvanic sludge in open areas.
 Methodology. The method is developed on the basis of a mathematical model that allows estimating changes in the depth of distribution and level of soil salinity over time using initial information about soil structure and its characteristics (molecular diffusion coefficient, volume humidity), annual volumes and conditions of sludge storage in the enterprise. Restrictions are set: the presence of harmful substances on the soil surface with a concentration that exceeds the permissible level; inadmissibility of harmful substances to aquifers.
 Results. The practical use of the method made it possible to identify the main dangers and predict the possibility of an emergency situation with negative environmental consequences during long-term storage of galvanic waste in open areas. The dynamics of soil salinity levels and the depth of penetration of heavy metals increase over twenty years of conservation has been determined, as well as the possibility of hazardous compounds entering groundwater has been assessed.
 Originality. The non-linear, non-stationary mathematical model is based on the theory of physico-chemical hydrodynamics of cellular media. The process of motion of metal salts has been described by the differential equation of motion and conservation of mass of matter for vertical mass transfer of matter.
 Practical value. Formalization of information about the hazards arising during the storage of industrial waste with chemically active elements allows to consider the subject area as a complex dynamic system consisting of objects of different nature, the totality of which determines the level of danger of emergencies with environmental consequences. The developed method makes it possible to transfer the obtained results to decision-making support systems, predicting possible consequences and material costs associated with post-emergency measures, motivating the management to take measures in advance.

Extraction and Analysis of Soil Salinization Information in an Alar Reclamation Area Based on Spectral Index Modeling

In order to explore the optimal remote sensing salinity monitoring index model for the inversion of soil salinization in the Alar reclamation area, based on the Sentinel-2 images and field measured data, the salinity index 1 (SI1), the normalized difference vegetation index in a green–red band (GRNDVI), the normalized vegetation index of greenness (GNDVI), and the normalized difference vegetation index (NDVI) were selected to construct the remote sensing-based salinization 1 detection index (S1DI) model. Next, the cotton field soil salinization information in the Alar reclamation area was extracted, and the accuracy of the model was verified to obtain the optimal remote sensing salinity monitoring index model. The results show that the overall classification accuracy of the S1DI1 (SI1-GRNDVI), S1DI2 (SI1-GNDVI), S1DI3 (SI1-NDVI), and S1DI4 (SI1-DVI) models for salinity monitoring is 83.35%, 83.10%, 82.96%, and 80.25%, respectively. The S1DI1 model is most suitable for retrieving the degree of soil salinization in the cotton field in the Alar reclamation area, and the S1DI2, S1DI3, and S1DI4 models are also very useful for monitoring soil salinization in the Alar reclamation area. Using the S1DI1 model to invert the soil salinization level of the cotton fields in the Alar reclamation area, it was found that the cotton field in the reclamation area is dominated by non-saline soil, and the light saline soil and moderate saline soil are mainly distributed in the 9th and 12th clusters of the reclamation area. As the S1DI1 model possesses the highest accuracy in extracting the soil salinization information of the cotton fields in the Alar reclamation area, it can be used as a remote sensing salinity 1 monitoring index model for the inversion of the soil salinization of the cotton fields in the reclamation area, which is expected to provide an effective reference value for soil salinization monitoring.

Salinisation of chernozem soils by brackish irrigation water in Southern Ukraine

ABSTRACT The waters of the South Bug and Kamianska irrigation systems present an average level of soil salinity hazard (ECw = 0.7-3.0 mS/cm) but salt concentration increases in the course of delivery, mainly through evaporation from the Stepivske, Danylivske and Katerynivske reservoirs. Soil salinity levels in the South Bug Irrigation System are less than 2 dS/m, nominally non-saline, but irrigation of Kamianska lands with more mineralised water has increased the salt content in the root zone, reaching ECe values of 4.0-6.0 dS/m, affecting the viability of vegetable crops and corn, but not wheat, barley, sugar beet and soybeans. Salinity is accompanied by an increase in sodium ions so there is a high probability of formation of sodic soils on Kamianska lands.

Effect of baikal em-1 microbiological fertilizer on growth and development of cotton

Level of soil salinity and water scarcity increases from year to year, it is necessary to increase the immune system of crops against diseases, pests and stressors, stable, high even in any unfavorable conditions. In the field experiment, 60-70% of the annual rate of phosphorus fertilizers, 50% of potassium was applied before autumn plowing, the rest of the rates of phosphorus fertilizers were applied together with nitrogen fertilizers during the flowering period, and potassium fertilizer was applied during the tillering period. The results showed that Baikal EM-1 (without mineral fertilizers) was sprinkled before plowing, before sowing seeds, on 3-4 true leaves, during pruning, flowering (10+10+3.0+3.5+3.5 l/ha) in the 8 variant, compared to the control variant (variant 1), the number of bolls decreased by 0.4 units, and the opening of bolls was around 30.0%.

Formulasi amelioran organik untuk menurunkan kadar salinitas tanah dan meningkatkan pertumbuhan tanaman padi di lahan salin

Soil salinity is still an obstacle that needs to be managed well on agricultural land located close to shoreline. The purpose of this study was to formulate an organic ameliorant to reduce soil salinity levels and increase the growth of rice plants on saline soils. The study was conducted in Jayamukti Village, Banyusari District, Karawang Regency from March to June 2022. Experiment used factorial randomized block design consisted of two factors with three replications. The first factor was the composition of organic ameliorant consisted of straw compost, husk charcoal, coconut shell biochar, dolomite, and humic acid. The second factor was the dose of organic ameliorant consisted of 0, 1, 2, and 3 tons/ha. The results showed that the application of organic ameliorant formulas in the form of 100% straw compost and 70% straw compost + 20% biochar + 10% dolomite at a dose of 3 tons / ha tended to be able to inhibit the decrease in saline soil acidity (0.15%) and reduce soil salinity levels (3.57%). The composition and dose of organic ameliorant interacted with each other in increasing the growth of rice plants by increasing plant height (40.10 cm) and number of tillers (6.00) compared to plants that were not given organic ameliorant on saline soil. Further research is needed on the efficacy test of the ameliorant formula in the field in increasing the growth and productivity of rice plants in saline land

Enhancing Rosemary (Rosmarinus officinalis, L.) Growth and Volatile Oil Constituents Grown under Soil Salinity Stress by Some Amino Acids

The current study was carried out during the two consecutive winter seasons of 2019/2020 and 2020/2021 at the Experimental Farm of Ash-Shoubak University College, Jordan, as a pot experiment. This experiment was planned to evaluate the impact of various soil salinity levels (1.17, 3.34, 6.51, and 9.68 ds/m) and amino acid types (control, L-tryptophan acid at 100 ppm, glutamine acid at 200 ppm, and L-tryptophan acid + glutamine acid) as well as their combinations on growth, salt resistance index, and some of the chemical constituents of rosemary plants. The obtained results indicated that plant height and the total herb dry weight of rosemary, the salt resistance index (SRI), and the total chlorophyll in leaves were discernably reduced with increasing soil salinity levels compared with the control. However, salinity enhanced leaf proline content. Each amino acid or its mixture improved plant growth, chlorophyll content, and SRI parameters. The SRI percentage of R. officinalis enhanced to more than 100% under a soil salinity level of 1.17 ds/m, combined with amino acids at any type, when compared with the other combination treatments. Furthermore, GC/MS showed that the identified compounds ranged from 98.39% to 99.18% and the unidentified compounds from 0.82% to 1.61% from the volatile oil of rosemary plants. The major constituents of volatile oil samples were camphor (34.95% to 40.21%), D-verbenone (13.74% to 15.23%), and α-pinene (13.21% to 16.73%).

Enrichment of keystone fungal taxa after flue gas desulphurization gypsum application drives reclamation of the saline‐sodic soil

AbstractSoil salinization is a major threat to sustainable agriculture in the western part of Songnen Plain, Northeast China. Flue gas desulphurization gypsum (FGDG) is commonly used for reclaiming of saline soils due to its high efficiency and cost‐effectiveness. However, the responses of soil and root‐associated fungi after FGDG amendment and the keystone fungal taxa in determining soil reclamation effect remain elusive. In this study, a long‐term field experiment was conducted to explore the effect of different levels of one‐time FGDG application on the soil reclamation and the herbage (Leymus chinensis) growth. Our results showed that the FGDG application greatly reduced soil salinity level, increased soil fertility and fungal diversity, and promoted aboveground biomass of L. chinensis, whereas reduced FGDG dose to 60% of gypsum requirement (GR) exhibited non‐significant difference on these characters compared with 100% GR treatment. We further discovered that both soil and root fungal communities were greatly changed after FGDG application, with root fungal community more sensitive than soil fungi. Through applying the Random Forest model, the arbuscular mycorrhizal fungi Glomeromycota was identified as the keystone taxa in predicting the soil salinity, soil fertility, and plant growth trait. Intriguingly, some Glomeromycota‐affiliated ZOTUs were consistently enriched in the FGDG application treatments, and acted as keystone hubs in the co‐occurrence network of fungal communities. Together, our study provides new insights that the enrichment of keystone Glomeromycota after FGDG application determines the reclamation of the saline‐sodic soil, which would guide the microbial‐based strategy for the development of degraded ecosystems.

Soil Salinity is a Serious Environmental Threat to Plant Diseases- A review

The rise in sea level, which causes an increase in salinity in both surface and ground water systems, is among the resultant effects of global climate change. Soil salinity is one of the notable environmental factors contributing to infectious plant diseases. Stress due to soil salinity affects plant tolerance to biotic stress by attenuating their immunity to pathogens leading to prevention of defence genes expression, reduced antioxidant activity and weakening of defence signalling proteins. The pathogen virulence and pathogenicity as well as an enhancement of pathogen development and multiplication are all influenced by soil salinity. Restriction of water absorption, toxic ion build up in plant tissues, nutrient deficiency, hormonal and metabolic imbalance, oxidative stress as physiological effects of salt stress, significantly affect the degree and occurrence of plant diseases. Thus, level of soil salinity is directly proportional to the severity and incidence of plant diseases. Controlling the effect of salinity by improving salinity tolerance in plants and deployment of salinity control measures will provide a long lasting solution on its effect on plant diseases. This will also serve as an approach to plant economic disease control.

Potential of Suaeda nudiflora and Suaeda fruticosa to Adapt to High Salinity Conditions

The deposition of salts in soil seems likely to become a significant barrier for plant development and growth. Halophytes that flourish in naturally saline habitats may sustain extreme salt levels by adopting different acclimatory traits. Insight into such acclimatory features can be useful for devising salt-resilient crops and the reclamation of saline soil. Therefore, salinity-induced responses were studied in two halophytes, i.e., Suaeda nudiflora and Suaeda fruticosa, at a high soil salinity level (ECe 65) to explore their possible tolerance mechanisms in their natural habitat. Samples of different tissues were collected from both Suaeda species for the determination of physio-biochemical attributes, i.e., ionic (Na+, K+, Ca2+, Cl−) content, osmo-protective compounds (proline, soluble sugars, soluble proteins), total phenolic content, and antioxidant components. Heavy metal composition and accumulation in soil and plant samples were also assessed, respectively. Fourier transform infrared spectroscopy (FTIR) analysis was conducted to explore cellular metabolite pools with respect to high salinity. The results showed that both species considerably adjusted the above-mentioned physio-biochemical attributes to resist high salinity, demonstrated by quantitative differences in their above-ground tissues. The FTIR profiles confirmed the plants’ differential responses in terms of variability in lipids, proteins, carbohydrates, and cell wall constituents. The high capacity for Na+ and Cl− accumulation and considerable bioaccumulation factor (BAF) values for metals, mainly Fe and Zn, validate the importance of both Suaeda species as phytodesalination plants and their potential use in the phytoremediation of salt- and metal-polluted soils.

Biological Response of Invasive Parthenium Weed to Elevated Concentration of Atmospheric Carbon Dioxide and Soil Salinity

Climate change elements including elevated atmospheric carbon dioxide (CO2) concentration and soil salinity significantly impact weed biology and management. In this study, we evaluated the performance of a highly invasive plant species, parthenium weed (Parthenium hysterophorus L.) grown at various soil salinity levels (ranging from 0 to 16 dS m−1) at two CO2 concentrations (ambient: 400 ppm and elevated: 700 ppm). The CO2 concentration and soil salinity individually affected various early growth attributes of parthenium weed. The interaction between CO2 and salinity was significant for chlorophyll index, stem dry weight and phenolics content. Parthenium weed plants grew taller (13%), achieved greater leaf area (28%) and produced more dry weight (24%) when raised under elevated as compared with the ambient CO2. Soil salinity had a dose-dependent, negative effect on various growth attributes, chlorophyll index, relative water content and phenolics content. Even the modest levels of salinity (4.2 to 4.6 dS m−1) caused 50% reduction in dry weights of leaves, roots and whole plants. Sodium ion (Na+) concentration peaked at the highest salinity level (16 dS m−1) as compared with the lower salinity levels (0 to 12 dS m−1). Overall, salinity had a negative effect on different growth variables but elevated CO2 improved growth and phenolics content regardless of the salt stress regime. Hence, parthenium weed could benefit from future atmospheric CO2 concentration and may invade some salt-affected areas.