Nonuniform Salt Research Articles

Localized and systemic abilities of arbuscular mycorrhizal fungi to control growth, antioxidant defenses, and the nutrient uptake of alfalfa under uniform and non-uniform salt stress

Localized and systemic abilities of arbuscular mycorrhizal fungi to control growth, antioxidant defenses, and the nutrient uptake of alfalfa under uniform and non-uniform salt stress

Salinity distribution pattern and its induced adaptability of tomato roots

Salinity is a major abiotic stress and threat to tomato production. Roots can attenuate salt stress at a specific salinity concentration, especially with non-uniform salinity distribution conditions, and may play a role in enhancing tomato plant adaptability to salt stress. Salt stress will also have a certain impact on root growth, which in turn affects the adaptability of crops to salt stress. Under different salt gradients, if we can find a reasonable distribution strategy, we can increase the tolerance of plants to salt stress. The hydroponics method was used and the roots were split into left and right parts. We established different salinity distribution patterns: a uniform salinity distribution T1 [0, 0], T2 [0.2%, 0.2%], and T3 [0.3%, 0.3%] and a non-uniform salinity distribution T4 [0.1%, 0.3%], T5 [0.1%, 0.5%], T6 [0.2%, 0.4%]. We observed the whole growth stage, and the plant's physiological responses to salt stress were measured. The data indicated that tomato plant roots can attenuate salt stress at a salinity concentration of 0.4%. The non-uniform salinity distribution can restrict root-uptake and uptake efficiency of nutrients (Na+, K+). Fruit yield, flavor and quality were enhanced by the non-uniform salinity distribution of T4 [0.1%, 0.3%]. Increased K+ led to a decreased Na/K ratio, which could reduce the toxicity of salt ions and improve tomato growth. The antioxidant enzyme activities of both roots and leaves of tomato plants were elevated under different salt stress patterns, indicating that the subject plants have the potential to exert adversity adaptations and that the enzyme activities are responsive to the degree of salt stress. Response of tomato fruiting stage growth and development and yield quality to different salt stresses. Growth adaptation of tomato under salt stress conditions. The above issues are discussed to provide a theoretical basis for the salt tolerance mechanism of tomatoes under non-uniform salt stress and the growth status of tomatoes on saline soils.

Effects of non-uniform salt stress on growth, yield, and quality of tomato

ABSTRACT Previous studies found that non-uniform salt stress could alleviate salt damage to plants compared to uniform salt treatment. The root system of tomato was divided into two parts, including salt-free treatment (NaCl concentrations were zero in both root systems), non-uniform salt stress with a NaCl concentration of 0.1% in one side of the roots (0.1%, 0.3%; 0.1%, 0.5%), non-uniform salt stress with a NaCl concentration of 0.2% in one side of the roots (0.2%, 0.4%), and uniform salt stress (0.2%, 0.2%; 0.3%, 0.3%) treatments. Compared with uniform stress, Na+ content in leaves decreased significantly (P < 0.05). The photosynthetic capacity of plants was significantly improved under the conditions of non-uniform salt treatment, which was mainly reflected in photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (Tr). Under mild salt stress, the stem and leaf weight of T13 in the non-uniform salt treatment increased by 7.60%, the yield per plant increased by 2.35%, and the total soluble sugar content increased by 6.85% compared with the uniform salt treatment T22. Under moderate salt stress, the stem and leaf weights of T15 and T24 in the non-uniform salt treatment increased by 14.62% and 5.77% compared with the uniform salt treatment T33, the yield per plant increased 6.04% and 3.49%, and the total soluble sugar content increased 18.94% and 7.97%. The study on the response of tomato under non-uniform saltinity was an important supplement to plant physiology under uniform saltinity, so as to provide references for cultivation and management in salt fields.

Contribution of dipolar bridging to phospholipid membrane interactions: A mean-field analysis.

We develop a model of interacting zwitterionic membranes with rotating surface dipoles immersed in a monovalent salt and implement it in a field theoretic formalism. In the mean-field regime of monovalent salt, the electrostatic forces between the membranes are characterized by a non-uniform trend: at large membrane separations, the interfacial dipoles on the opposing sides behave as like-charge cations and give rise to repulsive membrane interactions; at short membrane separations, the anionic field induced by the dipolar phosphate groups sets the behavior in the intermembrane region. The attraction of the cationic nitrogens in the dipolar lipid headgroups leads to the adhesion of the membrane surfaces via dipolar bridging. The underlying competition between the opposing field components of the individual dipolar charges leads to the non-uniform salt ion affinity of the zwitterionic membrane with respect to the separation distance; large inter-membrane separations imply anionic excess, while small nanometer-sized separations favor cationic excess. This complex ionic selectivity of zwitterionic membranes may have relevant repercussions on nanofiltration and nanofluidic transport techniques.

Non-uniform salt distribution in the root zone alleviates salt damage in wheat

Furrow sowing could significantly decrease salt damage to wheat; however, the molecular mechanism in wheat is not well known. In this study, a split-root system was used to simulate non-uniform root zone salinity. Our hydroponic experiments showed that wheat seedlings under non-uniform salt stress probably use a salt avoidance strategy to ensure growth. RNA sequencing analysis showed that 1648 and 3245 differentially expressed genes were identified in 0/150 and 75/75 salt treatments, respectively, with an intersection of 690 genes. Gene ontology terms representing normal growth were specifically enriched by upregulated genes in the 0/150 treatment and downregulated genes in the 75/75 treatment, and terms representing phytoremediation were specifically enriched by upregulated genes in the 75/75 treatment and downregulated genes in the 0/150 treatment. Differentially expressed genes that are probably associated with salt stress and transcription factors showed significantly higher expression in the 75/75 treatment than in the 0/150 treatment. These findings suggest that a uniform salt treatment causes wheat to initiate a more complex salt tolerance mechanism for salt stress. In addition, the expression of 11 genes annotated as peroxidase was higher in the 0/150 treatment than in the 75/75 treatment, and the enzyme activity showed the same trend, indicating that peroxidase probably played a role in the better performance of wheat plants under non-uniform salt stress. Pot culture experiments showed that wheat plants under non-uniform salt stress produced higher yields than those under uniform stress, further indicating that inducing unequal salt distribution in soil could significantly improve wheat cultivation.

Interactions between zwitterionic membranes in complex electrolytes.

We investigate the electrostatic interactions of zwitterionic membranes immersed in mixed electrolytes composed of mono- and multivalent ions. We show that the presence of monovalent salt is a necessary condition for the existence of a finite electrostatic force on the membrane. As a result, the mean-field membrane pressure originating from the surface dipoles exhibits a nonuniform salt dependence, characterized by an enhancement for dilute salt conditions and a decrease at intermediate salt concentrations. On addition of multivalent cations to the submolar salt solution, the separate interactions of these cations with the opposite charges of the surface dipoles makes the intermembrane pressure more repulsive at low membrane separation distances and strongly attractive at intermediate distances, resulting in a discontinuous like-charge binding transition followed by the membrane binding transition. By extending our formalism to account for correlation corrections associated with large salt concentrations, we show that membranes of high surface dipole density immersed in molar salt solutions may undergo a membrane binding transition even without the multivalent cations. Hence, the tuning of the surface polarization forces by membrane engineering can be an efficient way to adjust the equilibrium configuration of dipolar membranes in concentrated salt solutions.

Transcriptome analysis of genes and pathways associated with salt tolerance in alfalfa under non-uniform salt stress

Soil salinity of fields is often non-uniform. To obtain a better understanding of molecular response to non-uniform salt stress, we conducted transcriptomic analysis on the leaves and roots of alfalfa grown under 0/0, 200/200, and 0/200 mM NaCl treatments. A total of 233,742 unigenes were obtained from the assembled cDNA libraries. There were 98 and 710 unigenes identified as significantly differentially expressed genes (DEGs) in the leaves of non-uniform and uniform salt treatment, respectively. Furthermore, there were 5178 DEGs in the roots under uniform salt stress, 273 DEGs in the non-saline side and 4616 in the high-saline side roots under non-uniform salt stress. Alfalfa treated with non-uniform salinity had greater dry weight and less salt damage compared to treatment with uniform salinity. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the DEGs in roots revealed that both sides of the non-uniform salinity were enriched in pathways related to “phenylpropanoid biosynthesis” and “linoleic acid metabolism”; and “MAPK signaling pathway–plant” was also indicated as a key pathway in the high-saline roots. We also combined a set of important salt-response genes and found that roots from the non-saline side developed more roots with increased water uptake by altering the expression of aquaporins and genes related to growth regulation. Moreover, the hormone signal transduction and the antioxidant pathway probably play important roles in inducing more salt-related genes and increasing resistance to non-uniform salt stress on both sides of the roots.

Heterogeneous root zone salinity mitigates salt injury to Sorghum bicolor (L.) Moench in a split-root system.

The heterogeneous distribution of soil salinity across the rhizosphere can moderate salt injury and improve sorghum growth. However, the essential molecular mechanisms used by sorghum to adapt to such environmental conditions remain uncharacterized. The present study evaluated physiological parameters such as the photosynthetic rate, antioxidative enzyme activities, leaf Na+ and K+ contents, and osmolyte contents and investigated gene expression patterns via RNA sequencing (RNA-seq) analysis under various conditions of nonuniformly distributed salt. Totals of 5691 and 2047 differentially expressed genes (DEGs) in the leaves and roots, respectively, were identified by RNA-seq under nonuniform (NaCl-free and 200 mmol·L-1 NaCl) and uniform (100 mmol·L-1 and 100 mmol·L-1 NaCl) salinity conditions. The expression of genes related to photosynthesis, Na+ compartmentalization, phytohormone metabolism, antioxidative enzymes, and transcription factors (TFs) was enhanced in leaves under nonuniform salinity stress compared with uniform salinity stress. Similarly, the expression of the majority of aquaporins and essential mineral transporters was upregulated in the NaCl-free root side in the nonuniform salinity treatment, whereas abscisic acid (ABA)-related and salt stress-responsive TF transcripts were more abundant in the high-saline root side in the nonuniform salinity treatment. In contrast, the expression of the DEGs identified in the nonuniform salinity treatment remained virtually unaffected and was even downregulated in the uniform salinity treatment. The transcriptome findings might be supportive of the increased photosynthetic rate, reduced Na+ levels, increased antioxidative capability in the leaves and, consequently, the growth recovery of sorghum under nonuniform salinity stress as well as the inhibited sorghum growth under uniform salinity conditions. The increased expression of salt resistance genes activated in response to the nonuniform salinity distribution implied that the cross-talk between the nonsaline and high-saline sides of the roots exposed to nonuniform salt stress is potentially regulated.

Effects of non-uniform root zone salinity on growth, ion regulation, and antioxidant defense system in two alfalfa cultivars

A split-root system was established to investigate the effects of uniform (0/0, 50/50, and 200/200 mM salt [NaCl]) and non-uniform (0/200 and 50/200 mM NaCl) salt stress on growth, ion regulation, and the antioxidant defense system of alfalfa (Medicago sativa) by comparing a salt-tolerant (Zhongmu No.1) and salt-sensitive (Algonquin) cultivar. We found that non-uniform salinity was associated with greater plant growth rate and shoot dry weight, lower leaf Na+ concentration, higher leaf potassium cation (K+) concentration, lower lipid peroxidation, and greater superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6), and peroxidase (EC 1.11.1.7) activities, compared to uniform salt stress in both alfalfa cultivars. Under non-uniform salinity, a significant increase in Na+ concentration and Na+ efflux and a decline in K+ efflux in the no-saline or low-saline part of the roots alleviated salt damage. Our results also demonstrated that proline and antioxidant enzymes accumulated in both the no- or low-saline and high-saline roots, revealing that osmotic adjustment and antioxidant defense had systemic rather than localized effects in alfalfa plants, and there was a functional equilibrium within the root system under non-uniform salt stress. The salt-tolerant cultivar Zhongmu No.1 exhibited greater levels of growth compared to Algonquin under both uniform and non-uniform salt stress, with Na+ tolerance and efflux abilities more effective and greater antioxidant defense capacity evident for cultivar Zhongmu No.1.

Establishment of New Split-root System by Grafting.

A new split-root system was used to simulate non-uniform salt, drought or nutrient deficiency stress in the root zone, in which the root system was divided into two or more equal portions. Here, we established a split-root system by grafting of cotton seedlings. In contrast to the conventional split-root, the main roots of the new system remained intact, which provided a better system for studying cotton response to unequal treatment in the root zone. The new system was suitable for plant growth in nutrient solution and the two root systems can fully be immerged in the nutrient solution.

뿌리혹 형성능과 질소 고정능이 우수한 헤어리베치 유래 Rhizobium의 분리 및 선발

본 연구에서는 헤어리베치로부터 뿌리혹 형성능과 질소 고정능이 우수한 Rhizobium 균주를 분리하고자 하였다. 전국의 일곱 군데 헤어리베치 재배 지역에서 수집 후 뿌리혹으로부터 균주를 분리하였고, 헤어리베치에 분리 균주를 재접종하여 뿌리혹 형성능과 질소 고정능을 확인하였다. 그 결과, 52개의 Rhizobium 속 균주를 분리하였고, 이 중 0.5% NaCl 농도 이상에서 자라는 Rhizobium은 16균주이었다. 뿌리혹 형성능은 16개 균주 중 Rhizobium sp. RH1, RH3, RH81, RH82, RH84, RH93의 균주를 접종한 시험구에서 우수하였다. 또한, 질소 고정능을 확인한 결과 Rhizobium sp. RH84가 가장 높은 acetylene reduction activity를 보였다. 이러한 결과는 향후 염의 분포가 불균일한 간척지에 적용 시에도 헤어리베치의 생육을 촉진해 녹비 작물로의 활용 가능성을 높여주는 결과로 판단된다. This study was conducted to select rhizobia from hairy vetch (Vicia villosa Roth) with nodulation and excellent nitrogen-fixing ability. Hairy vetch root was collected from 7 of cultivation region of all over the country, rhizobia were isolated from the root nodules. Isolates were re-inoculated into a hairy vetch separately and studied nodulation and nitrogen-fixing ability. As a result, total of 52 Rhizobium isolates were isolated from the hairy vetch root nodules, among these, 16 isolates were Rhizobium which show good growth at more than 0.5% NaCl concentration. These 16 isolates were re-inoculated separately, 8 weeks after, good root nodule formation was observed from Rhizobium sp. RH1, RH3, RH81, RH82, RH84, and RH93 strain treated samples. Six isolates were positive for nitrogen fixing ability, the highest acetylene reduction activity was shown by Rhizobium sp. RH84. Results suggest that the Rhizobium sp. RH84 could be used as the possibility of its application as a green manure crop of hairy vetches in nonuniform salt distribution reclaimed land.

Controlling the Distribution of Supported Nanoparticles by Aqueous Synthesis

Synthesis of supported nanoparticles with controlled size and uniform distribution is a major challenge in nanoscience, in particular for applications in catalysis. Cryo-electron tomography revealed with nanometer resolution the 3D distribution of phases present during nanoparticle synthesis via impregnation, drying, and thermal treatment with transition metal salt precursors. By conventional methods a nonuniform salt distribution led to clustered metal oxide nanoparticles (NiO, Co3O4). In contrast, freeze-drying restricted solution mobility during drying and a more uniform nanoparticle distribution was obtained. By this fundamental insight into catalyst preparation, controlled synthesis of supported catalysts was achieved in a way that is also applicable for other nanostructured materials.

A whole-moon thermal history model of Europa: Impact of hydrothermal circulation and salt transport

A whole-moon numerical model of Europa is developed to simulate its thermal history. The thermal evolution covers three phases: (i) an initial, roughly 0.5Gyr-long period of radiogenic heating and differentiation, (ii) a long period from 0.5Gyr to 4Gyr with continuing radiogenic heating but no tidal dissipative heating (TDH), and (iii) a final period covering the last 0.5Gyr until the present, during which TDH is active. Hydrothermal plumes develop after the initial period of heating and differentiation and transport heat and salt from Europa’s silicate mantle to its ice shell. We find that, even without TDH, vigorous hydrothermal convection in the rocky mantle can sustain flow in an ocean layer throughout Europa’s history. When TDH becomes active, the ice shell melts quickly to a thickness of about 20km, leaving an ocean 80km or more deep. Parameterized convection in the ice shell is non-uniform spatially, changes over time, and is tied to the deeper ocean–mantle dynamics. We also find that the dynamics are affected by salt concentrations. An initially non-uniform salt distribution retards plume penetration, but is homogenized over time by turbulent diffusion and time-dependent flow driven by initial thermal gradients. After homogenization, the uniformly distributed salt concentrations are no longer a major factor in controlling plume transport. Salt transport leads to the formation of a heterogeneous brine layer and salt inclusions at the bottom of the ice shell; the presence of salt in the ice shell could strongly influence convection in that layer.

The effects of core zoning on the graphite lifespan and breeding gain of a moderated molten salt reactor

In the various one-fluid moderated Molten Salt Reactor (MSR) designs the ratio of the volume of the salt and the graphite is not uniform. This is usually realized by two or three zones in the core in which the volume ratio of graphite and salt is constant. This non-uniform salt distribution is used to increase the graphite lifespan or Breeding Gain (BG). However, it is difficult to assess the contribution of this non-uniformity to the final results of lifespan and BG based on the literature. In this paper, the effect of the variation of the salt distribution is investigated. As the aim of this study is to provide an insight to this single change of the core and to apply it to increase the lifespan of the graphite, the variations were performed only on the radial direction of the graphite–salt lattice in a cylindrical core. The obtained results were compared with a reference core in which the salt is distributed uniformly. It is possible to increase the breeding gain or the graphite lifespan by separating the core into two radial zones with different amount of graphite. On the other hand, it is only possible to increase one by the cost of decreasing the other one due to the change in the power distribution induced by the change in the core geometry.

Theory of the polyelectrolyte dielectric function

A simple double-layer polarization theory is developed for the flexible polyelectrolyte solution. Under the applied electric field, the double layer of the polyelectrolyte induces the excess line fluxes of charge and salt within the double layer. The off-diagonal Onsager coefficient couples the charge and the neutral salt dynamics so that the salt distribution is perturbed by the applied electric field. The nonuniform salt then drives the excess double-layer electric current. We show that the dielectric function can be expressed as the free energy storage and loss within the electric field and the salt distribution. At the leading Born approximation, the dielectric function depends on the chain configuration through the chain structure function. We use a simple mean-field structure function to calculate the dielectric function, where a closed-form expression is obtained. A detailed prediction is made for the full range of the polyelectrolyte concentration.

Using Direct‐Push EC Logging to Delineate Heterogeneity in a Clay‐Rich Aquitard

AbstractHeterogeneity exerts an important control on solute transport pathways in any subsurface environment, including aquitards where diffusion is the dominant transport mechanism. Direct‐push (D‐P) electrical conductivity (EC) logging has recently enabled high‐resolution hydrostratigraphic characterization of predominantly coarse‐grained sediments in low‐salinity aquifers. In this paper, we apply D‐P EC logging to characterize the spatial variability of physical and chemical properties in a clay‐rich aquitard that has known vertical contrasts in pore water salinity. The D‐P EC logging was conducted to a maximum depth of 17.5 m below ground (BG). Results obtained from 22 D‐P EC logs across a 140‐ × 80‐m field site were compared with pore water chemistry data from squeezed core samples (n= 21) and piezometers (n= 6) to reveal complex spatial variations in pore water salinity ranging from &lt;5000 to ∼90,000 μS/cm. The EC distributions appear to be controlled by nonuniform salt fluxes from the unsaturated zone to the water table and subsequent downward diffusion. Detailed D‐P EC logging also revealed the presence of a single discontinuous sand lens located between 9.4 and 15.9 m BG that may have important controls on solute transport pathways. The only limitation with using this method in very fine‐grained sediments is that depths of tool penetration may be considerably less than those currently achievable in sand and silt deposits.

Chemical heterogeneity in diffusion‐dominated aquitards

High‐resolution measurements of the three‐dimensional (3‐D) variability in pore water electrical conductivity (EC) were obtained at a clay‐rich aquitard research site (the King site, 120 m × 70 m area) in southern Saskatchewan, Canada, using direct‐push probing technology (n = 35 boreholes). These measurements revealed complex lateral heterogeneity in the subsurface salt distributions which raised questions on the validity of the commonly used approach of transposing chemical data from distributed piezometers onto 1‐D depth profiles for interpretation and solute transport modeling. Two‐dimensional numerical modeling simulations demonstrated that distributed, nonuniform salt inputs have existed at the top of the unoxidized till aquitard for the past 3–5 kyr. The source of the nonuniform salt inputs is unclear but may be due to either variations in microtopography (&lt;0.5 m) or variable penetration depth of surface fractures. A suite of generic solutions was developed to estimate the critical depth required to obtain chemical homogeneity in aquitards with nonuniform solute inputs and diffusion as the dominant transport mechanism. These solutions are presented for a range of sinusoidal input functions with varying amplitudes, magnitudes, and wavelengths. The solutions indicate EC distributions at the King site should be laterally uniform below a depth of around 20 m BG, which is consistent with observed EC values at the site. This study shows that aquitards with nonuniform salt inputs at their upper boundary are chemically heterogeneous above some critical depth and thus require careful attention when modeling solute transport processes within them.

Heated Mud Systems: A Solution to Squeezing-Salt Problems

Summary Squeezing salts have been a major problem to operating companies worldwide for many years. Most previous solutions to the problem have been aimed at treating the symptoms rather than the cause. Generally, these have been based on running casings capable of withstanding the nonuniform salt loadings because satisfactory cementations have been virtually impossible to achieve because of large washouts in the salt layers. The solution is to use standard oilfield equipment to drill a gauge hole through the squeezing salts, thus providing an optimum cementation environment. Various methods were used to try to resolve the problem; the last was the use of thick-walled casings in conjunction with saturated potassium/ magnesium drilling fluids to reduce salt washout. Unfortunately, washouts still occurred because the muds could not be saturated at the surface to downhole conditions. Now, the drilling fluid is heated on the surface, enabling the required level of salt concentration to be achieved. The heating system, comprising a boiler and heat ex-changer from a conventional well-test package, has been used on eight wells to date. In each case, a gauge hole was drilled through the squeezing-salt sections and, subsequently, successful cementations were performed.

Growth, Nutrition, and Water Uptake of Tomato Plants with Divided Roots Growing in Differentially Salinized Soil1

AbstractTomato (Lycopersicon esculentum Mill. var. VF 145) plants were grown in the greenhouse to determine effects of uniform and nonuniform salinity distribution on root growth and on water and N uptake. The plants were grown in Reiff sandy loam (Coarse‐loamy, mixed, nonacid, thermic Mollic Xerofluvents) using a technique by which the root system was divided and each of four quadrants allowed to grow in separate compartments. Nutrient solutions differing in salinity levels (1, 4, 7, and 10 dS/m; nonuniform treatment) were applied to the four compartments, or all four received a nutrient solution otherwise similar but with a salinity of 5.5 dS/m (uniform treatment). The salinization was brought about by a mixture of NaCl and CaCI2 in a ratio of 1:1 by weight. To determine sources of N taken up, sufficient K15NO3 was added to provide 2% 15N in the solution. Yields of shoots and roots were lower for the plants grown with the uniform than the nonuniform salinization treatment. With nonuniform salt distribution, about 62 and 8% by weight of the total root system were found in the compartments irrigated with nutrient solutions having initial salinities of 1 and 10 dS/m, respectively. About 63% of the total water taken up per plant was drawn from the compartment with the lowest salinity. With the uniform salt distribution treatment, N uptake into the shoots was more severely affected than growth. With treatments in which salinity was nonuniformly distributed, the main source of N was the compartment with the lowest salinity. The contribution of this compartment, however, decreased during the growing period as its relatively greater salinity buildup favored uptake of N by roots in the other compartments, initially irrigated with the more saline solutions. Plants growing in the units with the nonuniform salinity treatment generally showed lower leaf concentrations of Ca, Na, K, and Cl, but higher leaf concentrations of Mg and P than the plants growing in the uniformly salinized units. Unlike the other elements, K and P concentrations decreased with time. Differences in S concentrations as related to salinization treatments were variable during the growth period. Higher concentrations of the “bound” organic anion fraction, but lower concentrations of the “diffusible” fraction, as determined from differences in amounts of inorganic cations and anion present, were found in leaves of plants grown with the higher salinity levels. In general, for nutrition of tomato plants grown under conditions in which different regions of the root system are exposed to differences in salinity, the least saline environment is dominant, but over time root activity shows some accommodation to the presence of salt.

Calculation of the Leaching required to Reduce the Salinity of a Particular Soil Depth beneath a Specified Value

AbstractSoil columns containing either Yolo silty clay loam or Hanford sandy loam were prepared with vertically nonuniform salt (Na+, Ca2+, Mg2+, Cl‐) and moisture distributions and with gypsum (CaSO4 · 2H2O) present in the surface soil. The columns were irrigated at both fast and slow rates of water application with a water containing Na+, Ca2+, Mg2+, and Cl‐. A simple method for calculating salt movement in soils successfully approximated the resultant salt profiles.A variation in the salt movement computation method was devised for calculating the leaching required to lower the salinity of a particular soil depth to less than a specified value. The method was experimentally verified on both a Yolo and a Hanford soil column, each with vertically nonuniform initial salt and moisture distributions.