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Soil salinity is considered one of the main types of soil degradation in semiarid environments around the globe. This work aims to evaluate the effectiveness of soil conditioners to enhance the growth and salt extraction ability of Salicornia ramosissima for different soil moisture contents. Salicornia plants were cultivated in pots in which the soils were treated with the following conditioners: control; gypsum + organic matter; elemental sulfur + organic matter; and gypsum + elemental sulfur + organic matter. Salicornia plants were subjected to two soil moisture rates - at 35 and 85% field capacity. Soil conditioners associated with higher contents of soil moisture promoted significant increases, compared to control, in fresh (6.20 - 11.13 g) and dry matter (1.20 - 2.07 g), relative biomass (100 - 179%) as well as significantly increased the concentrations of Na+ (56.09 - 65.64 mg kg-1) and Cl- (110.83 - 150.0 mg kg-1) in plant tissues. Soil conditioners significantly increased salt extraction ability under the two moisture levels, mainly by promoting higher values for both transfer factor and phytoremediation potential. The best performance of Salicornia in terms of plant yield and salt extraction, regardless of the moisture level, was the gypsum + organic matter.Novelty statementThere are no studies in the literature relating the use of conditioners as a strategy to enhance Salicornia's ability to extract salts.This work contributes to the management of salinized areas around the globe in two main aspects. The first is that many of these salt-degraded areas are desertified and through this study, it is possible to revegetate and recover them. The second one is that, since Salicornia is a plant with economic value, this can serve as an incentive for farmers to grow Salicornia in saline areas.

Tidal flat reclamation generates several excavated saline-sodic soil slopes. However, there are limited studies on the hydraulic flow characteristics and dynamic erodibility of saline-sodic soil sl...

Rice straw compost (RC) and water treatment residuals (WTR) can improve both organic wastes recycling and soil physical properties of salt-affected soils. Therefore, the aim of this study was to te...

The aim of the research is the dissipation of Phenanthrene in sodic soil in the presence of PGPR by two mucilagenous plant species (Trigonella foenum-graceum and Brassica juncea). To evaluate of af...

Tryptophan role in microbial biosynthesis of Indole Acetic Acid (IAA) is very distinct. In present study IAA producing bacteria Pseudomonas moraviensis was applied on wheat for improving gr...

The aim of this study was to ascertain the utility of using the freshwater snail Ampullaria tischbeini as a biological control agent for the remediation of soil impacted with high levels of...

Amendments are commonly applied to soil to ameliorate sodic conditions, but their effect on improving microbial activity depends on the severity of sodicity and the types and rates of amendments ap...

Poor soil physical conditions associated with low hydraulic conductivity and infiltration can limit salt leaching and reclamation; hence, land revegetation. Soil physical amendments such as wood chips and fine sand may be used to remediate the soil physical conditions and improve salt leaching, thus assisting with revegetation. To evaluate the success of soil amendments for the reclamation and revegetation of a saline-sodic soil under a typical climatic condition of a semi-arid environment, a water and solute transport model (HYDRUS-1D) was used. Synthetic climatic scenarios were generated using LARS-WG. Soil profiles (1 m depth) amended separately with 20% wood chips and 40% fine sand at the surface (0–10 cm) were defined for the simulation. A non-amended soil profile, which had physical properties of a disturbed soil, was used as a control. Salt leaching was more successful in the non-amended soil profile compared with the amended soil profiles. The likelihood and the success of Atriplex halimus L. seed germination were also higher in the non-amended soil (67.7%) compared with wood chips (13.98%) and fine sand (6.7%) amended soils. This study indicates that the addition of 20% wood chips and 40% fine sand to the depth of 10 cm of a saline-sodic soil may not be an effective approach for reclamation and revegetation under the semi-arid climatic conditions. This study suggests that a reduction in soil bulk density is sufficient to provide suitable conditions for successful land reclamation and revegetation in the investigated climatic conditions.

Attempts were made to ameliorate sodic black calcareous soils by using different crop residues (composted cotton stalk and biomulch 5 t ha−1, respectively) and green manures (in-situ Crotalaria juncea, Sesbania aculeata, Vigna unguiculata, Vigna radiata, and ex-situ Leucaena leucocephala loppings 5 t ha−1) and gypsum 2.5 t ha−1. The organic amendments were outperformed with respect to improvement in soil microbial biomass carbon and dehydrogenase activity, not gypsum. The application of dhaincha significantly improved the mean weight diameter by 14% over control. The application of gypsum and dhaincha recorded a significant drop in pHs (0.1 and 0.07 units) and exchangeable sodium percentage (26.7% and 20.6%) over control. After 2 years of experiments, dhaincha (14.8%) and sunhemp (15.5%) also showed the commensurable potential of improving yields of chickpea as compared to gypsum (14.8%) over control. Hence, dhaincha and sunhemp can be a better alternative choice to gypsum in sodic soils.

Soil salinity is a major limiting factor for crop production in arid and semi-arid regions of northwest China. Flue gas desulfurization gypsum (FGDG) is valuable waste resource which can be used to improve saline soil. Monolith lysimeter leaching experiment was conducted with FGDG in heavily saline-sodic soil of northwest China. The four FGDG treatments with nine replicates for each treatment were applied when the FGDG rate was 0, 15, 30, and 60 t ha−1, respectively. Undisturbed sodic-saline soil was carefully collected in the 40-cm deep soil column. The results indicated that improvement effect on the depth of 0–10 cm soil layer was the best when the rate of FGDG was 60 t ha−1. It can reduce pH by 1.85, exchangeable sodium percentage (ESP) by 44%, and exchangeable Na+ by 7.37 cmol/kg in top soil layer. The values of the above soil parameters fell in the normal range due to FGDG treatment. At the same time, FGDG application reduced soil bulk density and increased saturated hydraulic conductivity. ...

This study aimed to evaluate the use of phytoremediation and soil conditioners in the recovery of physical attributes of a saline-sodic Fluvic Neossol in Brazil Northeast. The applied treatments were: Atriplex nummularia L., as phytoremediation plant, due to its ability to extract salts from the soil; organic conditioners, such as bovine and sheep manure; gypsum and polymer, as chemical conditioners. Samples with preserved structure were collected at the time of the experiment installation and 18 months after in the layers 0–10 cm and 10–30 cm. The analyzed attributes were: water dispersed clay, dispersion index, bulk density, penetration resistance, soil porosity, and saturated hydraulic conductivity. The use of sheep manure, gypsum and polymer promoted an increase in saturated hydraulic conductivity in the 0–10 cm layer from 4.51 to 16.37 cm day−1, 11.26 to 23.95 cm day−1 and 7.24 to 22.77 cm day−1, respectively. Gypsum increased the macroporosity in the superficial layer by 42.6%. Atriplex and ...

The reclamation of saline sodic soils requires sodium removal and the phytoremediation is one of the proven low-cost, low-risk technologies for reclaiming such soils. However, the role of Phragmites australis in reclaiming saline sodic soils has not been evaluated extensively. The comparative reclaiming role of P. australis and gypsum was evaluated in a column experiment on a sandy clay saline sodic soil with ECe 74.7 dS m-1, sodium adsorption ratio (SAR) 63.2, Na+ 361 g kg-1, and pH 8.46. The gypsum at 100% soil requirement, planting common reed (P. australis) alone, P. australis + gypsum at 50% soil gypsum requirements, and leaching (control without plant and gypsum) were four treatments applied. After 11 weeks of incubation, the results showed that all treatments including the control significantly reduced pH, EC, exchangeable Na+, and SAR from the initial values, the control being with least results. The gypsum and P. australis + gypsum were highly effective in salinity (ECe) reduction, while sodicity (SAR) and Na+ reductions were significantly higher in P. australis + gypsum treatment. The reclamation efficiency in terms of Na+ (83.4%) and SAR (86.8%) reduction was the highest in P. australis + gypsum. It is concluded that phytoremediation is an effective tool to reclaim saline sodic soil.

Reclamation of sodic soils is proving increasingly vital as greater land area becomes salt-affected in the northern Great Plains of the United States. Flue gas desulfurization gypsum (FGDG) can be an agriculturally important resource for increasing land productivity through the amelioration of sodic soils. Biochar is also considered as an aid in reclaiming degraded soils. In this incubation study, two rates of FGDG (33.6 Mg ha−1 and 66.2 Mg ha−1), two rates of biochar made from sugar beet (Beta vulgaris L.) pulp (16.8 Mg ha−1), and one rate of FGDG combined with one rate of biochar (33.6 Mg ha−1 ea.) were applied to a sodic soil. Soil physicochemical properties, including cationic exchange, pH, electrical conductivity (ECe), sodium adsorption ratio (SARe), total organic carbon (TOC), water retention, and soil respiration rate, were assessed during and at the end of the incubation period. Addition of FGDG to sodic soil increased ECe from 3.5 to 8.4 dS m−1 and decreased SARe from 16 to 9. Biochar ad...

In the context of widespread saline and sodic soil, mapping and monitoring spatial distribution of soil salinity and sodicity are important for utilization and management in agriculture lands. In this study, two-stage assessment was proposed to predict spatial distribution of saline and sodic soils. First, artificial neural network (ANN) and multiple linear regressions (MLR) model were used to predict sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP) based on soil electrical conductivity (EC) and pH. Then, the Kriging interpolation method combined with overlay mapping technique was used to perform saline spatial predictions in the study area. The model accuracy level is evaluated based on coefficient of determination (R2) and root mean square error (RMSE). In the first stage, the values of R2 and RMSE of SAR and ESP were 0.94, 0.17 and 0.94, 0.24 for ANN, and 0.35, 0.52 and 0.34, 0.76 for MLR, respectively. Similarly, in the second stage, the RMSE of ANN-Kriging were much clos...

The experiment on the effect of primary biomethanated spentwash (PBSW) on soil properties, nutrient uptake and yield of wheat on sodic soil was carried out at a research farm of Post Graduate Institute, Mahatma Phule Krishi Vidyapeeth, Rahuri, Maharashtra state, India, during the post-monsoon season. The experimental soil was sodic calcareous having Sawargaon series of isohyperthermic family of Vertic Haplustepts. The experiment was laid out in a randomized block design with nine treatments and three replications. The treatments consisted of varying doses of PBSW (100, 200, 300, 400 and 500 m3 ha−1), absolute control, farmyard manure (FYM) 5 t ha−1 + RDF-AST (recommended dose of fertilizer as per soil test), FYM 5 t ha−1 + 50% GR (gypsum requirement) + RDF-AST and FYM 5 t ha−1 + 100% GR + RDF-AST. The results revealed that the physical properties, namely bulk density and hydraulic conductivity, were improved in sodic soil due to the application of increased doses of PBSW. A significant reduction i...

The field experiments on calcareous sodic Vertisols were conducted on farmer’s fields in Purna valley of Vidarbha region of Maharashtra. The treatments comprised of different green manures (GMs); crop residues (CRs); gypsum. The chemical and biological properties after 2 years experiment showed that the application of gypsum recorded significant drop in pH and exchangeable sodium percentage (ESP) as compared to organic amendments. But later has outperformed with respect to biological activities viz., dehydrogenase activity (DHA) and microbial respiration and carbon sequestration by enhancing soil organic carbon (SOC), soil organic carbon (SOC) stock, soil microbial biomass carbon (SMBC) and labile carbon pool (POXC). Among the different organic amendments the application of dhaincha improved SMBC by 90%, microbial respiration by 104%, POXC by 59% and DHA by 265% as compare to control. High ESP of these soils showed negative relationship with microbial respiration and POXC (r = 0.48 and r = 0.43, p...

An attempt has been made in the field conditions to evaluate the effect of atmospheric temperature rise on yield, ionic ratio (Na:K), and accumulation of antioxidative pigments in wheat in different growth stages under different soils. Five planting windows (PW) were classified, based on date of wheat sowing where the average temperature difference between a particular PW and PW-I varied from 1.33–4.24°C. Plant leaf area and root length density showed decreasing trend with increasing temperature. A low flag leaf water potential (−1.14 MPa) in sodic soil and high solute potential (−1.34 MPa) in saline-sodic soil was observed under PW-V, where high temperature difference (4.24°C) was recorded. The Na:K ratio was found to be highest in both straw and grain which were 1.802 and 1.126%, respectively, under saline-sodic conditions in PW-V. Proline and malondialdehyde concentration was highest under sodic conditions which varied between 2.82–2.95 mg g−1 fresh weight (FW) and 18.38–30.18 nmol g−1 FW, resp...

This survey examined the element toxicities in wheat grown in naturally waterlogged farmer's sodic fields. Seven sites located in three districts (Faizabad, Pratapgarh, and Ambedkar Nagar) of eastern Uttar Pradesh, India were selected for the study. The data on soil redox potential (Eh), soil pH, soil electrical conductivity (EC), waterlogging duration, and crop age during waterlogging were recorded at the time of plant sampling in all the sites. Waterlogging caused a reduction of 21% to 65% in shoot dry weight in the survey sites. During waterlogging, the concentrations of iron (Fe), aluminum (Al), and sodium (Na) in leaves increased dramatically; the values of these elements were many folds higher than their reported critical toxicity levels (Fe-100 ppm, Al-50 ppm, and Na-8000 ppm, respectively). The results support the hypothesis that element toxicities occur during waterlogging in wheat grown in farmer's sodic field and identified Fe, Al, and Na toxicities as a major constraint for wheat produ...

A pot experiment was conducted on saline-sodic soil following sorghum-oat and rice-wheat crop rotations and amending with gypsum (G), farm manure (FM), and mulch (M). Water of different qualities viz. electrical conductivity (EC) 0.6 + sodium adsorption ration (SAR) 6, EC 1.0 + SAR 12 and EC 2.0 + SAR 18 was used for irrigation. The results showed that one pore volume (PV) of brackish water with higher EC and SAR ratio may be used beneficially, if proper amendments are applied. For rice and oat crops, the order of effective amendments was G>FM>M>control (C). With sorghum and wheat, the order was FM>G > M > C. Salt removal from soils was the lowest when leaching fraction (LF) was 0.20 and was the highest when LF was 0.32, i.e. a direct positive relationship. This proposes that irrigation water and the salt accumulated in the profile should be measured after short intervals to avoid reoccurrence of salinity.

Application of sand can ameliorate rice paddy fields converted from saline–sodic land. However, the requirement of huge amount of sand has been limiting its practical application. In this study, flushing during saline sodic-sensitive stages of rice plant growth was incorporated into the ameliorating system to reduce the sand usage. A split-plot design was adopted with sand application (SA) with two levels as main plots and flushing during the sensitive stages (FL) with two levels as subplots in a hard saline–sodic soil, Northeast China. Four treatments included CK (no-sand, no-flush flooding), NF (non-sand, flush flooding), SN (sand, no-flush flooding), and SF (sand, flush flooding). The results showed that both SA and FL significantly affected all the investigated yield parameters. The combined effect of SA and FL on the grain yield was additive in the first year in respect of the effect on panicle density and seed weight per panicle; while it showed synergistic effect on the seed weight per panicle and grain yield in the second year. The rice yield in different treatments was in the order of SF > SN > NF > CK in both years, with the highest yield (4.37 t ha−1) obtained by SF treatment in the second year. Our results demonstrate that half the traditional amount of sand in combination with water-flushing during the saline–sodic-sensitive growth stages of rice is sufficiently effective in ameliorating saline–sodic soil and thereby enhancing rice grain yield in saline–sodic paddy fields.

A study was conducted to evaluate the effects of different land uses and soil-management systems (LU and SMS) on key soil physicochemical indicators [aggregate stability, distribution of soil organic carbon (SOC), and nitrogen (N) in aggregate fractions] and to interpret significance of long-term cultivation of agroforestry plantations [Prosopis juliflora L. (AFP) and Casuarina equisetifolia L. (AFC)], horticultural plantations [(Tamarindus indica (HI) and Syzygium cumini (HJ)], and rice–wheat system (RW) in sodic soil of the Indo-Gangetic plain. Soil samples collected from the different LU and SMS plots were analyzed. The barren sodic soil (BSS) exhibited the least mean weight aggregate diameter (0.21), whereas AFP recorded the greatest (0.59). Total N content in surface soil under RW system was about the same as AFP, AFC, HI, and HJ and significantly greater than BSS. Across the LU and SMS except BSS, microaggregates recorded a narrower C/N ratio than macro- and mesoaggregates.

Two halophytes, Salicornia europaea and Atriplex verucifera, and the non-halophyte Chenopodium album were grown in pots on sodic and non-sodic Iranian soils spiked with up to 100 mg Cd kg−1. The halophytes grew best on the sodic soil in the absence of Cd spiking, while C. album performed better on non-sodic soil. Cadmium spiking reduced the growth of all plants, with Cd tolerance decreasing in the order S. europaea>A. verucifera>C. album. The observed order of Cd tolerance corresponds to the abilities of the plants to tolerate sodic soil properties. The variation of Cd concentration in shoots in response to sodicity was related to different mechanism, including dilution (C. album) Cd solubilisation by Ca2+ (S. europea) and Ca2+ competition for uptake and translocation of Cd (A. verucifera). Improved understanding of these complex interactions will help to design phytoextraction technology for Cd-polluted soils in arid regions.

The relative effects of Na + and K + on soil structural stability due to application of some conditioners in sodic soils are not clearly defined by the existing literature. In this research, a completely randomized design experiment was performed to quantify the effect of some conditioners on physical properties in a loamy sodic soil. Five treatments included no conditioner as a control, urban solid waste compost (MC), Vermi-compose (VC), poultry manure (PM), and gypsum powder (G). The amount of each soil amendment was 10 ton/ha and each treatment consisted of 3 replications. The most important structural stability indicators including air capacity (AC), water dispersible clay (WDC), the slope of the retention curve at the inflection point (S gi index), and mean weight diameter of aggregates (MWD) were measured. The results showed that compared with the control, soil conditioners improved soil structural stability indicators significantly (P

Participatory variety selection (PVS) for the selection and testing of salt tolerant varieties/genotypes and breeding accessions of rice was conducted at Central Soil Salinity Research Institute, Regional Research Station, Lucknow, Uttar Pradesh, India from 2001 to 2007. This aimed to identify high yielding, adaptable, and acceptable rice cultivars for sodic soils through farmers’ participation. Typically, plant breeders develop varieties isolated from active farmers and release varieties that are most productive under ideal conditions; often they are not suitable for marginal farm conditions, like sodic lands. Therefore, PVS facilitates development of varieties suitable for marginal soils and farmers’ interests. A collection of modern rice varieties/genotypes was screened and evaluated under researcher-managed trials during 2001. From 2002 to 2008, farmers became a part of the variety/genotype selection and testing process in order to incorporate their preferences, which were crucial for the large-scale ...

A factorial design with different levels of elemental S and cow manure was used to investigate the effects of S and manure on SO4-S, P and micronutrient availability in a calcareous saline–sodic soil. The results revealed that the recovery of SO4-S increased significantly (p≤0.05) in all treatments as elemental S increased, particularly when in combination with manure. The interactional effects of S° and manure application rates resulted in a decrease in soil pH of 0.1 to 0.9 units and increases in soil EC from 0.1 to 2.6 dS m−1 as result of an increase in the number of oxidisers and the oxidation rate of elemental S. Application of S° in combination with manure led to an increase in soil-available-P (0.6–40 mg kg−1), DTPA-Zn (0.2–3.9 mg kg−1) and DTPA-Fe (0.1–5.6 mg kg−1).

In this study, efficacies of mined gypsum and phosphogypsum (PG), when applied at equivalent doses, were compared for sodic soil reclamation and productivity of rice–wheat system. Application of PG, followed by karnal grass as first crop, resulted in the greatest reduction of soil pH and exchangeable sodium percentage (ESP) followed by PG applied at 10 Mg ha−1 alone. Application of PG at 10 Mg ha−1 resulted in greater yields of both rice and wheat than other treatments. Ditheylenetriaminepentaacetic acid (DTPA)–extractable micronutrients of PG-treated soil were greater than in mined gypsum–treated soil. A greater portion of applied P entered the calcium (Ca)–phosphorus (P) fraction in PG-treated soil, which also resulted in more soluble P than the mined gypsum–treated soil. Phosphogypsum effected greater increase in aggregation, soil organic carbon, microbial biomass carbon, and aggregate associated carbon and decrease in zeta potential, leading to increased hydraulic conductivity and moisture retention c...

Seriphium plumosum encroachment in South Africa has converted extensive areas of grassland into less productive shrubland–grassland, but its control is not being seriously addressed at present. Therefore, the short-term response of S. plumosum to different applications of nitrogen (N), phosphate (P), lime, sodium chloride (NaCl) and a soil-applied suspension herbicide, Molopo (active ingredient tebuthiuron), was examined. The lime and P-fertiliser treatments lead to no deaths of S. plumosum for any of the concentrations. The smaller the shrubs, the more sensitive they were to both N and NaCl applications. The minimum N-fertiliser applications of 30, 60, 120, 1 000 and 2 000 kg ha−1 were responsible for 100% death of shrubs with heights of 200, 300, 400, 500 and 600 mm, respectively. Sodium chloride application of only 100 kg ha−1 lead to 100% death of shrubs smaller than 400 mm high. Although high applications of NaCl led to total death of shrubs 600 mm high, the enormous problem of saline/sodic soil acco...

The field experiment on effect of primary treated biomethanated spentwash (PBSW) on physiochemical and biological properties of soil and yield of sunflower (Helianthus annuus L.) on sodic soil was conducted at the Postgraduate Farm, Mahatma Phule Agricultural University, Ahmednagar, India, during 2008–9. The experiment was laid out in a randomized block design (RBD) with nine treatments [control, varying doses of PBSW (30, 60, 90, 120, 150, and 180 m3 ha−1), farmyard manure (FYM) + recommended dose of fertilizer (RDF), and FYM + gypsum at 50% gypsum requirement (GR) + RDF] with three replications. The FYM dose was 5 Mg ha−1. The experimental soil was sodic calcareous, being of the Sawargaon series of isohyperthermic family of Vertic haplustepts with high exchangeable sodium percentage (ESP), low available nitrogen (N) and phosphorus (P), and high available potassium (K). The results revealed that the physical properties [bulk density, mean weight diameter (MWD) of water-stable aggregates, and hydraulic co...

The discharge of saline groundwater results in the formation of sodic soil scalds in irrigated, dryland and urban environments of southeastern Australia. Sodic soils are dispersive, and this leads to soil erosion and a loss in agricultural productive capacity. These sodic soils commonly show polygonal cracking and pressure ridges indicating the presence of swelling clays. Infrared spectroscopy of scald surfaces and XRD (X-ray diffraction) analyses of the clay fractions of the sodic soils show the presence of amorphous clays, smectite, illite or mixed smectite/illite layer clays. Non-salinised soils adjacent to the salt scalds are commonly predominantly kaolinitic. SEM images and normative EDS mineral analyses of the clay fractions of these soils show that crystalline particles, predominantly of kaolinite, are progressively replaced by poorly crystalline smectite, illite and amorphous material. Normative mineral analyses determined from the bulk soil composition, based on a derived composition of submicron...

The removal of sodium salts from saline soils by salt tolerant crops, as alternative for costly chemical amendments, has emerged as an efficient low cost technology. Lysimeter experiments were carried out on a highly saline sodic soil (ECe = 65.3 dS m(-1), ESP = 27.4, CEC = 47.9 cmole+ kg(-1), and pH = 7.7) and irrigated with canal water (EC = 2.2 dSm(-1), SAR = 4.8) to investigate reclamation efficiency under four different treatments: control (no crop and no gypsum application) (C), gypsum application equivalent to 100% gypsum requirement (G100), planting sea orach (Atriplex halimus) as phytoremediation crop (Cr), planting sea orach with gypsum application equivalent to 50% gypsum requirement (CrG50). Soil salinity (ECe) and exchangeable sodium percentage (ESP) were significantly reduced compared to the control. Average ESP and ECe (dS m(-1)) in the top layer were 9.1, 5.8 (control), 4.8, 3.7 (Cr), 3.3, 3.9 (CrG50), and 3.8, 3.1 (G100), respectively. Atriplex halimus can be recommended as phytoremediation crop to reclaim highly saline sodic clay loam soils.

Soil sodification in Northeast China is controlled by many other factors besides groundwater level. This research aims to explore the mechanism of sodium buildup in sodic soil based on in-situ observation and laboratory analysis. Results indicate that water and sodium redistribution process on the soil surface at local scale was an additional factor leading to the rapid soil sodification development in Songnen Plain in recent decades. A field observation was conducted in a 35x35m2 area. Mollisols were distributed in depressions and free of natric horizon, while Halaquepts were found on micro slopes and high flats. A natric horizon was found at a depth of 15-30cm in high flats, with an exchangeable sodium percent (ESP) value of 70. Fluctuation of groundwater table in the freezing period was related, to some extent, to the formation and development of frozen soil. During the freezing period, groundwater table was gradually lowered as a result of the groundwater moving into the frozen layer, leading to higher moisture content therein. During the thawing period, soil moisture content in the surface layer of Mollisols showed a significant enrichment (p0.05) from 0.27 to 0.69m3m-3(over-saturated). Salt in the surface of Halaquepts enriched quickly, especially in the micro slope, by about 80%. In comparison, insignificant change was observed in Mollisols. Sodic soil should be leveled fully and adequate drainage should be utilized before farming in order to prevent soil sodification. Blocking the capillary pore channels between topsoil and subsoil by plowing before freezing season would help soil desodification in high-latitude arid and semiarid regions.

A Long-term field study was carried out to compare the impact of ten-year old plantation of ten multipurpose tree species, viz., Terminalia arjuna, Azadirachta indica, Prosopis juliflora, Pongamia pinnata, Casuarina equisetifolia, Prosopis alba, Acacia nilotica, Eucalyptus tereticornis, Pithecellobium dulce, and Cassia siamea on tree growth, biomass yield, and physico-chemical properties of sodic soils representing major tract of salt-affected soils of the Indo-Gangetic Alluvial Plains of India. Maximum (100%) survival was recorded with Terminalia arjuna, Prosopis juliflora, Pongamia pinnata, and Pithecellobium dulce whereas minimum (50%) in Prosopis alba. Maximum plant height (9.3 m) was recorded with Eucalyptus tereticornis followed by Casuarina equisetifolia (8.2 m) whereas; minimum plant stature was attained by Cassia siamea. Prosopis juliflora reported maximum diameter at stump height, crown diameter, lopped biomass, and litter fall at all the growth stages. Prosopis juliflora also produced highest a...

The adverse effects of sodicity on plant growth are difficult to quantify using naturally occurring soils because of the confounding variation in other soil properties, particularly salinity, pH, organic matter, soil nutrients, mineralogy, and texture. We applied a method involving the equilibration of large soil volumes with solutions varying in sodium adsorption ratio (SAR), followed by excess salt removal with solutions of similar SAR but lower ionic strength. Application of this method to a calcareous nonsodic, nonsaline Vertosol from Narrabri, New South Wales, resulted in soils with exchangeable sodium percentage (ESP) values between 2% and 25% but with similar magnesium and potassium concentrations and constant electrical conductivity (∼2.7 dS/m). Soil pH and solution phosphorus concentrations automatically increased as the ESP of the soil rose, which is important to consider when addressing plant growth results. This method can successfully minimize the confounding of sodicity with other soil prope...

Salt affected soils are characterized by variable distribution and dynamic nature. Based on Landsat data from 1986/1987 supported by ground truth, salt affected soil maps were prepared at 1:250,000 scale for 14 states and a union territory (UT). A map legend was evolved that described the nature, degree and extent of salt affected soils suitable for varied physiographic and agroclimatic regions of the country. Fifteen categories of salt affected soil were identified for the entire country. These were merged to two categories – saline and sodic – for management purposes. Digitized maps were developed in a geographical information system (GIS) depicting salt affected areas of the country. An area of 6.73 million ha of salt affected soils was estimated for the entire country. State-wise estimates showed that this extensive area is distributed over the Gangetic plain of Uttar Pradesh; the arid and semiarid regions of Gujarat and the peninsular plains of Maharashtra state. A significant area is also located in...

A field experiment was conducted on sodic soil during its rainy seasons of 2004 and 2005 to evaluate five germplasms of Ocimum basilicum (viz. CSLT 5, CSLT 9, CSLT‐12, CSLT‐12‐1, and CSLT‐13) for their growth performance, their oil yield, chemical constituents of their oil, and ion‐partitioning characteristics in different parts of the plants. The highest shoot yield was recorded in CSLT‐12, followed by CSLT‐9 and CSLT‐13. The highest oil yield was recorded in CSLT‐13, followed by CSLT‐12‐1. This indicated that a high herbage yield does not always result in a high oil yield. Germplasm CSLT‐12 and CSLT‐12‐1 seemed to have better adaptation in sodic soil then other germplasms on the basis of root architecture and root density. Germplasm CSLT‐5 was of the linalool chemotype, yielding 62.36% linalool in oil, whereas CSLT‐13 and CSLT‐9 were methyl chavicol chemotypes, yielding 69.59% and 56.98% of methyl chavicol, respectively. Germplasms CSLT 12 and CSLT 12‐1 are intermediate types that yielded 48.86...

Efficient and sustainable reclamation of sodic soils is important to agricultural production. With the help of a peristaltic pump, laboratory-leaching experiments for sodic calcareous soils with exchangeable sodium percentage (ESP) of 1, 12.5, and 19 were conducted under atmospheric CO2 partial pressure to investigate native CaCO3 mineral dissolution and its contribution to the rehabilitation of moderate sodium-affected soils at the water flow velocities of 2 and 18 mm h−1, respectively. The electrical conductivity (EC), pH, and the Ca2+, Mg2+, Na+, K+, Cl−, and HCO3 − concentrations in the leachates were measured. The exchangeable Na+ contents in the soils after leaching were measured and their ESPs were calculated. Results indicated that both soil sodicity and water flow velocity significantly affected native CaCO3 dissolution and sodic soil reclamation. Almost all of the Ca2+ to substitute the adsorbed Na+ came from the native CaCO3 dissolution. The CaCO3 dissolution rate decreased logarithmically with...

Soil salinization and sodication affect large areas of agricultural land in the world. Amelioration of these soils to make them suitable for agricultural production depends on understanding sodium dynamics and chemical interactions governing nutrient availability. Three locations in eastern Croatia were characterized to the 5-m depth. The two solonetz-solonchak soils were alkaline, whereas the solonetz soil had near-neutral A/E horizon and alkaline deeper horizons. Electrical conductivity of the saturated extract (ECe) was greater than 4 dS m-1 in the top horizons in the solonetz-solonchak soils. The solonetz soil had 2.8-4.7 dS m-1 in shallow A/E, CG, and G horizons and up to 6.3 dS m-1 below 1.5 m. Highly alkalinized sodic horizons (exchangeable sodium percentage, ESP >20) had 24-47% Ca2+ and 27-33% Mg2+ on the cation exchange complex. Sodium adsorption ratio (SAR) was high (18-26) in the P horizon and even more so in Bt, na horizon (35-36) of solonetz-solonchak soils. A strong negative exponential relationship existed between soluble Ca2+ and SAR (SAR increased greatly when Ca2+ dropped to around 3 mg dm-3). An increase in pH to greater than 8.4 resulted in an exponential increase in SAR. Leaching of Na+ with successive volumes of water was similarly effective for the P and Bt, na horizons in the solonetz-solonchak soils, but SAR remained greater than 15 even after six successive cycles of leaching. In conclusion, extensive amelioration of tested soils with gypsum and leaching will be required to overcome poor physical and chemical characteristics caused by various degrees of alkalization and sodication to bring these soils into production.

The present study aimed to investigate the effects of K-type and Ca-type artificial zeolites on the growth and water and element absorptions of kidney bean (Phaseolus vulgaris L.), tomato (Lycopersicon esculentum Mill), maize (Zea mays L.) and beet (Beta vulgaris L.) in high sodic soil. Tottori sand dune soil, which was used as a control, was converted to high sodic soil mixed with salts. Each type of zeolite was mixed into the high sodic soil at rates of 0, 1, 2 and 5%. The results showed that kidney bean, tomato and maize died in high sodic soil 25–27 days after transplanting (DAT), whereas beet survived, although its growth was extremely suppressed at 26 DAT. The addition of Ca-type zeolite improved growth in all of the tested plants. Even 4 DAT the growth of beet was improved by recovery of water absorption, and growth of tomato was improved by recovery of Ca and K absorptions and cation balance, and restriction of Na absorption. Growth of kidney bean and maize improved at 11 or 13 DAT by rec...

Results of laboratory and field tests suggest that chelating agents could be used to alleviate adverse soil properties caused by excess sodium, such as low permeability. Adding multi-dentate carboxylic acid chelating agents to sodic soil, or to mixtures of soil with sodium-contaminated waste, significantly reduced sodium adsorption ratio (SAR) values. Judging from cation concentrations in saturated paste (sat. paste) filtrates, chelating agents act to ameliorate soil sodicity by releasing Ca and to a lesser extent Mg from undissolved compounds. After adding chelating agents to moist soils that contained free lime, measured weight losses were consistent with CO 2 evolution due to CaCO 3 decomposition. The electrical conductivity (EC) of the sat. paste filtrate of materials treated with chelating agents increased less than when equivalent Ca or Mg was supplied in conventional, soluble form. Bigger sat. paste vacuum filtration volumes, improved soil permeability and faster field infiltration rates were obser...

Phosphorus (P) availability to plants in reclaimed alkali soils was the main objective of this study, which was also focused on P transformations, decrease in Olsen‐P content, and magnitude of P lost in leachate in course of amendment application and leaching. Liquid sodium bicarbonate (NaHCO3) was added to nonalkali soils to set up four ESP (exchangeable sodium percentage) levels (viz., 2.9, 25.0, 50.0, and 75.0), but actual ESP levels obtained were 2.9, 24.6, 51.2, and 75.3. Amendments (viz., gypsum and pyrites) and P treatments (viz., 0 and 50 mg P Kg−1) were mixed with dry, sieved soil before filling into PVC (polyvinyl chloride) drainage columns, which were then compacted to uniform bulk density and leached with deionized water for 30 days. Results indicated that the pH and electrical conductivity (EC) of the soils increased with increase in ESP level of the soil but decreased with amendment application. Phosphorus addition to alkali soils decreased the pH on day 30, but it could not affect ...

Performance of three, evenaged leguminous tree species (Acacia nilotica, A. auriculiformis and Pithecellobium duke) was evaluated on sodic soil sites (pH 9.6) at Biomass Research Centre, Banthra, Lucknow (north India). Species differed significantly in respect to plant survival, growth and productivity since beginning of its growth as observed at the age of five, 10 and, 15 years. Acacia nilotica had highest average girth at breast height (60.5 cm) and stand biomass (161 Mg ha-1) in spite of its lowest plants survival after 15 years of growth. A. auriculiformis ranked next to it with 131 Mg ha-1 productivity. Basal area ranged from 12.8 to 23 m2 ha-1 in different species. P. duke performed poorly as it had only 71 Mg ha-1 of biomass. Average leaf area per hectare in different species ranged from4,129 m2 ha-1 to 16,090 m2 ha-1 after 15 years of growth. A. nilotica also showed superiority in respect to energy content in woody biomass (2,467 GJ ha-1) and fuel wood value index (1694) as compared to t...

Kangping soil in northeast China is a sodic soil characterized by a high pH and excessive sodium. The high pH and excessive sodium in sodic soils generally cause loss of soil structure, reduce hydraulic conductivity (HC), increase soil hardness, and make the soil unproductive land. After we mixed organic matter (rice straw) and chemical amendments (H2SO4, CaSO4, and FeSO4), a column experiment was conducted to evaluate the physical and chemical properties of the soil influenced by the changes in HC, penetrability of soil s`urface, pH, electrical conductivity, CO3 2‐, HCO3 −, Ca2+, Na+, sodium adsorption rate (SAR), available phosphorus (P) and iron (Fe), and leached P. Organic matter decreased the concentrations of CO3 2‐, HCO3 −, and Na+ in soil solution and increased the total volume of the leachate. Organic matter also reduced the amount of available Fe and increased the available P. However, organic matter did not affect the penetrability of the soil surface as much as soil hardness, HC, and ...

The study was conducted with the objective of studying tree species diversity and dominance and the associated changes in soil characteristics in a man-made forest established on formerly barren sodic land at Banthra Research Station (National Botanical Research Institute, Lucknow, India) (80° 45–53′ E, 26° 40–45′N) over three decades. The results revealed that the forest has a moderate value for the tree species diversity index (H). The tree species Derris indica, Dalbergia sissoo, Azadirachta indica, Cassia siamea, Terminalia arjuna, Syzygium cumini, and Tectona grandis were found to be the major dominant species which may be considered suitable for planting on such degraded wastelands. There was a perceptible reduction in soil pH and exchangeable sodium percentage (ESP) and an increase in organic C and Ca2++Mg2+ cation contents over the past three decades, indicating that the sodicity has declined in the surface soil.

Amelioration of sodic soils requires the supply of Ca2+ to replace the excess Na+ present on the soil exchange complex. Tree planting on sodic soil produces CO2 that enhances the solubility of CaCO3 present in the sodic soil, and thus releases an appreciable amount of soluble Ca2+ that replaces Na+ from the exchange complex. The study indicates that the sodic soil gets desodified and becomes suitable for plant growth. The study was carried out in 9-year-old rehabilitated plots in the Sultanpur district of Uttar Pradesh, India, to evaluate the relative effects of Prosopis juliflora, Dalbergia sissoo, and Eucalyptus tereticornis plantations on sodic soil and their tolerance of sodicity. The study showed that the saturated soil paste extract Ca2+ and Mg2+ concentrations increased significantly in all the plantations, whereas Na+ concentration decreased from the surface to lower layers. Due to the reduction in Na+ concentration and increase in Ca2+ and Mg2+ concentration, the Sodium Adsorption Ratio (SAR) als...

The impact of calcium (Ca) supply on the growth and yield of rice was studied in nutrient and soil culture experiments. In solution culture experiment, the effect of external‐Ca supply (0.5, 1.0, 1.5, 2.0, 3.0, 4.0 mM Ca) on the growth and shoot composition of two rice cultivars, varying in salt‐tolerance, in the presence and absence of 100 mol m− 3 NaCl was measured in a four week trial. In soil culture experiment, Ca (as gypsum; CaSO4 · 2H2O) was applied at the rates of 0, 10, 25, 50 and 100% of gypsum requirement (GR) of the saline‐sodic soil (after determining its GR). A positive, improving and stimulative effect of Ca was noted in growth characteristics (shoot and root weight and tillering capacity) in both the cultivars at 1.0 to 1.5 mM Ca; above this concentration, Ca had inhibitory effect. Although increasing supply of Ca tended to decrease sodium (Na) and chloride (Cl) concentration in the shoots of both rice cultivars, shoot‐concentrations of Na and Cl were much lower in NIAB‐6 (salt tolerant) t...

A field study was initiated in 9-year-old rehabilitation plots, in the Sultanpur district (26° 10'-26° 40'N, 81° 45'-82° 30'E) of Uttar Pradesh, India, to evaluate the efficiency of Prosopis juliflora, Dalbergia sissoo, and Eucalyptus tereticornis to improve the chemical properties of sodic soil. It was found that the soil reaction and exchangeable Na + percentage had declined and the amount of organic C, Kjeldahl N, NaHCO 3 extractable P, and NaOAc K + had increased in all the three plantations under study. P. juliflora proved more efficient in reducing soil pH, displacing Na + from exchange complex and raising the organic carbon and nutrient status in comparison to D. sissoo and E. tereticornis.

Beets were grown on soils with various exchangeable sodium percentages (ESP). A saline non-sodic soil (SA, ESP = 3.2), a saline sodic soil (SO, ESP = 23), and a saline high sodic soil (HSO, ESP = 78) were prepared from Tottori sand dune soil (CO). K-type and Ca-type artificial zeolites (50 g kg−1) were applied to these soils in order to evaluate their effects on the chemical properties of saturation extracts of the soils, water deficit, cation uptake and transport, and cation balance of beet plants. In the zeolite-free treatments, beet growth was accelerated in SA and SO, but was suppressed in HSO compared with CO. The addition of both types of zeolites ameliorated plant growth in all the soils studied, especially HSO. The relative dry weight of the soils treated by the K-type zeolite to the zeolitefree soil was 189% for CO, 125% for SA, 130% for SO, and 222% for HSO. For the soils treated with the Ca-type zeolite, the values were 169, 116, 132, and 341%, respectively. In SA, SO, and HSO, the add...

Utilization of salt affected wasteland by growing forage shrubs has enormous economic and environmental implication for developing countries like Pakistan, where approximately 6.3 million ha of the land is salt affected. Considering the importance of Atriplex and Maireana species, research has been conducted using their different species on the salt affected soils of Faisalabad. Most of Atriplex and Maireana species survived under the environmental conditions of Faisalabad and gave the good yield in the form of forage. Some of these species are woody and can be used for fuel purposes. Sixteen genotypes of Atriplex and Maireana were tested for their tolerance to waterlogging in order to identify halophytic fodder shrubs suitable for growth on secondary salt-affected and waterlogged farmland. The physiological and morphological responses of the species tested were typical of species with a generally poor tolerance to waterlogging. Despite this, some species (e.g., A. amnicola) were surprisingly resistant, s...

Zinc (Zn) deficiency is often reported on rice crops growing in sodic soils. Thirty rice genotypes were tested for their tolerance to Zn deficiency and sodicty stresses by transplanting 35-days old seedlings in pots having sodic soil of pH2 (1 : 2 soil water ratio) 9.8, and DTPA-extractable Zn 1.8 ppm;. Ten genotypes (Group A) showed potential to tolerate both the stresses with better survival (73–100%), tillering and were free from any visible symptoms of either Zn deficiency or sodium (Na) toxicity on their leaves. Sixteen genotypes (Group B) including CSR10, a tolerant check to sodicity, were found sensitive to Zn deficiency with less survival (35–80%), poor tillering and with visible symptoms of Zn deficiency. However, some of the seedlings of these genotypes were free from visible symptoms of Zn deficiency. Four genotypes (Group C) were sensitive to sodicity (survival 3–13%) and exhibited symptoms of Na toxicity within a week of transplanting. Analysis of the top three leaves and their leaf sheaths a...