Use Of Saline Water For Irrigation Research Articles

Application of fulvic acid and potassium fertilization to reduce the harmful effect of salt water stress on growth, productivity and nutritional status of tomato plants

Water is a key resource for sustainable agricultural development in Egypt. The scarcity of fresh water resources in Egypt has led to the use of salt water for irrigation. Therefore, the aim of the research was to study the effect of potassium fertilization and spraying with fulvic acid on tomato plants irrigated with salt water and grown in sandy soil during two successive growing seasons. Different rates of the potassium fertilization combined with different concentrations of fulvic acid foliar application. The rates of K fertilization were 150, 200 and 300 Kg K2O per hectare of the recommended fertilizer unit (300 kg K2O ha-1). While, the concentrations of fulvic acid were 500, 1000 and 2000 mgl-1. Increasing the spraying concentration of fulvic acid from 500 to 2000 ppm resulted in a significant improvement in the parameters of growth, quantity and quality yield of tomato plants with an increase in potassium fertilization rates from 150 to 300 K2O kg ha-1with the use of saline irrigation water. Increasing the concentration of fulvic acid spraying led to the uptake of nitrogen, phosphorus and potassium in tomato leaves increased with an increase in potassium fertilization rates.Therefore, it can be said that spraying fulvic acid with the use of potassium fertilization is one of the successful solutions in reducing the effect of irrigation with salt water on the growth and yield of tomato plants.

Effect of sufficient and deficit irrigation with different salt inputs on the yield of cucumber

Soil salinisation is considered one of the major environmental hazards threatening agricultural productivity and can be accentuated by climate change as well as the use of low-quality water in irrigation. This is the case in our study area which is affected by secondary salinisation due to the use of saline irrigation water for horticultural production. Deficit irrigation technique is implemented especially in arid and semiarid regions due to its potential to optimise water productivity while maintaining or increasing crop yield. The main objective of this study was to compare the effect of irrigation with sufficient (SD) and deficit (DD) doses. This research was carried out in Karcag in 2020. Cucumber was grown on a meadow chernozem soil and was irrigated with SD and DD of two irrigation water qualities. Soil moisture was monitored and crop yields were recorded. Despite the differences in quality and quantity of water, the application of less water by DD maintained the same yield as SD. We found a non-significant difference between the average soil moisture contents under the treatments (15.5 v/v% for SD and 13.5 v/v% for DD). Deficit irrigation can be an efficient technique due to its potential for improving water use efficiency, maintaining sufficient soil moisture content favourable for proper crop development and yield.

Reducing Water Salinity at Flowering Stage Decreases Days to Flowering and Promotes Plant Growth and Yield in Chile Pepper

Water scarcity is a major problem for crop production around the world including Southwestern United States and growers are increasingly using groundwater for agriculture in Southern New Mexico. Most of the groundwater in New Mexico is brackish and continuous long-term use could lead to salt accumulation in the soil. Reverse osmosis (RO) can desalinate brackish groundwater (BGW), however, environmentally safe disposal of RO concentrate is costly. This greenhouse study evaluated the effects of BGW and RO concentrate at various growth stages of two chile pepper cultivars, NuMex Joe E. Parker and NuMex Sandia Select. Five salinity treatments were applied to plants, three of them used saline waters of 0.6 (control), 4.0 (BGW), and 8.0 dS/m (RO) throughout the growing season, whereas the other two changed waters of 4.0 and 8.0 dS/m to waters of 2.0 and 6.0 dS/m from the beginning of the flowering stage. Number of flowers, days to flowering, relative plant heights, relative fresh biomass, fruit yields, photosynthetic rate (Pn), stomatal conductivity (gS), and actual evapotranspiration (ETa) significantly decreased with increasing irrigation water salinity levels. Concentrations of Mg2+, Na+, and Cl− in plants increased with increasing water salinity levels. Changing to irrigation with reduced salinity waters of 2.0 and 6.0 dS/m at the flowering stage initiated reproductive development more rapidly and alleviated the adverse influence of salinity on the number of flowers of chile pepper, plant height, Pn, as well as fresh shoot and fruit weight than that with continuous irrigation with electrical conductivity (EC) of 4.0 dS/m and 8.0 dS/m beyond the flowering stage. Irrigation that practices a change from high salinity to lower salinity at the flowering stage can optimize the use of saline irrigation water for growing chile peppers.

Soil Moisture Influence on the FTIR Spectrum of Salt-Affected Soils

Soil salinity has a major impact on agricultural production. In a changing climate with rising sea-levels, low-lying coastal areas are increasingly inundated whereby saltwater gradually contaminates the soil. Drought prone areas may suffer from salinity due to high evapotranspiration rates in combination with the use of saline irrigation water. Salinity is difficult to monitor because soil moisture affects the soil’s spectral signature. We conducted Fourier-transform infrared spectroscopy on alluvial and sandy soil samples in the coastal estuary of the Red River Delta. The soils are contaminated with NaCl, Na2CO3 and Na2SO4 salts. In an experiment of salt contamination, we established that three ranges of the spectrum were strongly influenced by both salt and moisture content in the soil, at wavenumbers 3200–3400 cm−1 (2.9–3.1 µm); 1600–1700 cm−1 (5.9–6.3 µm); 900–1100 cm−1 (9.1–11.1 µm). The Na2CO3 contaminated soil and the spectral value had a linear relationship between wavelengths 6.9 and 7.4 µm. At wavelength 6.99 µm, there was no relationship between absorbance and soil moisture, but the absorbance was proportional to the salt content (R2 = 0.85; RMSE = 0.68 g) and electrical conductivity (R2 = 0.50; RMSE = 3.8 dS/m). The relationship between soil moisture and spectral absorbance value was high at wavelengths below 6.7 µm, resulting in a quadratic relation between soil moisture and absorbance at wavelength 6.13 µm (R2 = 0.80; RMSE = 5.2%). The spectral signatures and equations might be useful for mapping salt-affected soils, particularly in difficult to access locations. Technological advances in thermal satellite sensors may offer possibilities for monitoring soil salinity.

Effects of Irrigation with Desalinated Water on Lettuce Grown under Greenhouse in South Korea

This study assessed the effects of irrigation with desalinated water on the growth of lettuce (Lactuca sativa L.). Two experiments, the first using saline and the second desalinated irrigation water, respectively, were designed to grow lettuce in plots (22 m × 0.4 m × 0.4 m) under controlled greenhouse conditions. Three levels of saline irrigation water and tap water (control) were used for the first experiment. In the second experiment, the three saline levels underwent a desalination process. Each experiment was carried out twice, in succession, with two replications. The results from the first experiment showed that the use of saline irrigation water caused an increase in the salinity level of soil and, consequently, adversely affected lettuce growth and yields. The results from the second experiment showed that the use of desalinated irrigation water does not negatively affect soil salinity and lettuce growth and yield. However, the need for additional application of the elements such as Ca2+ and Mg2+ was also identified since continued use of desalinated water irrigation correlated with a decrease in the sodium adsorption ratio (SAR), leading to increased risk of soil sodicity. This is due to the elimination of nutrients during the desalination process.

Evaluating the Sustainable Use of Saline Water Irrigation on Soil Water-Salt Content and Grain Yield under Subsurface Drainage Condition

A sustainable irrigation system is known to improve the farmland soil water-salt environment and increase crop yields. However, the sustainable use of saline irrigation water under proper drainage measures still needs further study. In this study, a two-year experiment was performed to assess the sustainable effects of saline water irrigation under subsurface drainage condition. A coupled model consisting of the HYDRUS-2D model and EPIC module was used to investigate the effects of irrigation water salinity (IWS) and subsurface drainage depth (SDD) on soil water-salt content and summer maize yield when saline water was adopted for irrigation under different subsurface drainage measures. Summer maize in the two-year experiments were irrigated with saline water of three different salinity levels (0.78, 3.75, and 6.25 dS m−1) under three different drainage conditions (no subsurface drainage, drain depth of 80 cm, and drain depth of 120 cm). The field observed data such as soil water content, soil salinity within root zone, ET and grain yield in 2016 and 2017 were used for calibration and validation, respectively. The calibration and validation results indicated that there was good correlation between the field measured data and the HYDRUS-EPIC model simulated data, where RMSE, NSE (> 0.50), and R2 (> 0.70) satisfied the requirements of model accuracy. Based on a seven × seven (IWS × SDD) scenario simulation, the effects of IWS and SDD on summer maize relative grain yield and water use efficiency (WUE) were evaluated in the form of a contour map; the relative grain yield and WUE obtained peak values when drain depth was around 100 cm, where the relative yield of summer maize was about 0.82 and 0.53 at IWS of 8 and 12 dS m−1, and the mean WUE was 1.66 kg m−3. The proper IWS under subsurface drainage systems was also optimized by the scenario simulation results; the summer maize relative yield was still about 0.80 even when the IWS was as high as 8.61 dS m−1. In summary, subsurface drainage measures may provide important support for the sustainable utilization of saline water in irrigation. Moreover, the coupled HYDRUS-EPIC model should be a beneficial tool to evaluate future sustainability of the irrigation system.

Soil salinity, leaching, and cotton growth as affected by saline water drip irrigation and N fertigation

ABSTRACTSaline water (SW) irrigation is necessary in parts of the world where supplies of good quality water are limited. The aim of this study was to learn more about the use of saline irrigation water in drip-irrigated cotton. Therefore, a 5-year field experiment consisted of a 3 × 2 factorial complete randomized block design with three levels of irrigation water salinity (0.35, 4.61, and 8.04 dS m−1) and two N application rates (240 and 360 kg N ha−1) was carried out in arid regions of northwestern China. The results indicated that drip irrigation with SW (4.61 or 8.04 dS m−1) increased average soil water content and average soil salinity in the 0–100 cm depth. SW irrigation increased leachate –N concentrations. Nitrogen rate significantly affected leachate volume and salt concentration in some years; however, the trends were inconsistent. The treatment with 8.04 dS m−1 irrigation water significantly reduced cotton growth, yield, and N uptake in all the five cropping seasons. In contrast, the treatment with 4.61 dS m−1 water increased cotton growth, yield, and N uptake in the first year, but in the third, fourth, and fifth years, cotton growth, yield, and N uptake were significantly lower in the treatment with 4.61 dS m−1 water than in the treatment with 0.35 dS m−1 water. Cotton growth and yield increased as N application rate increased; however interactive effects between water salinity and N rate on cotton growth and yield were generally not significant. We conclude that drip irrigation with SW (EC>4.6 Ds m−1) reduces cotton yield and increases the risk of salt and –N leaching to groundwater. Additional N fertilizer input may overcome some of the negative effects of salinity on cotton growth, but also increases the potential risks for nitrate leaching.

The role of humic substances in mitigating the harmful effects of soil salinity and improve plant productivity

The environmental, social and economical reasons indicate that the conventional agriculture constitute a continuous pressure contributing to the progressive worsening of environmental conditions, especially by an increasing apply high level of inputs. In this matter, the increasing use of saline irrigation water is one of the main factors resulting in salt accumulation in the plant rhizosphere influencing both physical, chemical and biological soil properties and agroecosystem productivity. In this situation, soil degradation emphasized the need to develop strategies of salt effected soil reclamation. One of the possible solutions is to use humic substances (HS), since there is an increasing need to their utilization in agriculture. They are the major components of soil organic matter, have multiple roles in plant growth and are the subject of study in various areas of agriculture, such as soil chemistry, soil fertility and plant physiology. Thus, our hypothesis account for a beneficial effect of HS in salt affected rhizosphere likely due to a 'direct' action on the plant together with an 'indirect action' on the metabolism of soil microorganisms, the dynamics of uptake of soil nutrients and soil physical conditions. In this paper we review the HS formation and components and their influences on improving saline soil properties as both direct and indirect effects. Keywords: Humic substance; Salt accumulation; Soil degradation; Plant productivity; Hormone-like activity.

Possibilities for use of saline irrigation water for higher land productivity under groundnut – mustard rotation in salt affectedVertisolsof Saurastra in Gujarat

A field experiment was conducted to assess the possibility for use of saline irrigation water in kharif groundnut (Arachis hypogeae L) and rabi mustard (Brassica junceae L) during 2005–06 and 2006–07 for higher land productivity of black clayey Vertisols. The experiment was conducted on fixed site. The soil was shallow, clayey, low to medium in fertility and calcareous in nature underlain by weathered or hard milliolithic limestone. The treatments using randomized block design with three replications were consisted of four salinity levels of irrigation water (0.5, 2, 4 and 6 dSm−1 salinity). Five different cultivars of Spanish bunch group groundnut were grown in each plot. Results indicated that irrigation water of 2 and 4 dSm−1 could be safely used as supplementary irrigation in groundnut depending on rainfall as well as native soil salinity and in mustard crop. The germination of groundnut was delayed by 3–4 days under saline water irrigation. The most vulnerable plant growth stages affected by water salinity were pod formation (No. of pods and pod weight per plant) in groundnut and initial plant growth stage like plant stand, plant height and days to flowering in mustard crop. The ‘rate of’ root zone salinity buildup was higher at lower water salinity level which was subsequently decreased with increased levels of salinity of irrigation water. It was clearly evident from the results that mustard crop was more resistant to salinity hazards as compare to groundnut crop.

Assessing Tolerance to Sodium Chloride Salinity in Fourteen Floriculture Species

The use of saline irrigation water may be inevitable in the future since the freshwater supply is decreasing over time. In some regions of the United States, producers of both ornamental and agronomic crops are already facing a limited supply of high-quality water. Therefore, it is necessary to determine the salt tolerance of commonly used greenhouse bedding plants to minimize potential salt damage before use of nonpotable water sources is mandated. Research screening several bedding plants has not taken place for more than two decades. Therefore, we undertook experiments to screen popular bedding plants for salt tolerance during greenhouse production. Transplants were exposed to 0 (control), 20, 40, 60, or 80 mm sodium chloride (NaCl) in the irrigation water for 5 weeks resulting in average substrate pour-thru electrical conductivity (EC) values of 4.0 (control), 7.0, 9.8, 12.1, or 14.2 dS·m−1, respectively. Pansy (Viola tricolor) and zinnia (Zinnia angustifolia), the most sensitive species examined, exhibited 100% mortality when exposed to an EC of 14.2 dS·m−1. The least affected species for dry weight (DW) was snapdragon (Antirrhinum majus) with a 54% reduction as EC increased from 4.0 to 14.2 dS·m−1. Only fuchsia (Fuchsia hybrida) and snapdragon were unaffected by an EC of 7.0 dS·m−1, whereas at 9.8 dS·m−1 all of the species had a significantly reduced DW as compared with control plants. Verbena (Verbena ×hybrida), petunia (Petunia ×hybrida), coleus (Solenostemon scutellarioides), and begonia (Begonia hiemalis) were the only species that did not undergo a significant height reduction in comparing 9.8 dS·m−1 to control. A classification of the 14 species is created here on the basis of plant DW to provide guidance as to which species could be irrigated with more saline water while not compromising plant growth and quality.

Development and application of a conceptual hydrologic model to predict soil salinity within modern Tunisian oases

In modern oases situated in the south of Tunisia, secondary salination of irrigated lands is a crucial problem. The visible salt deposits and soil salination processes are the consequence of several factors including the excessive use of saline irrigation water, seepage from earthen canal systems, inefficient irrigation practices and inadequate drainage. Understanding the mechanism of the secondary salination is of interest in order to maintain existing oases, and thus ensure the sustainability of date production in this part of the country. Therefore, a conceptual, daily, semi-distributed hydrologic model (OASIS_MOD) was developed to analyse the impact of irrigation management on the water table fluctuation, soil salinity and drain discharge, and to evaluate measures to control salinity within an oasis ecosystem. The basic processes incorporated in the model are irrigation, infiltration, percolation to the shallow groundwater, soil evaporation, crop transpiration, groundwater flow, capillary rise flux, and drain discharge. OASIS_MOD was tested with data collected in a parcel of farmland situated in the Segdoud oasis, in the south-west of Tunisia. The calibration results showed that groundwater levels were simulated with acceptable accuracy, since the differences between the simulated and measured values are less than 0.22 m. However, the model under-predicted some water table peaks when irrigation occurs due to inconsistencies in the irrigation water data. The validation results showed that deviations between observed and simulated groundwater levels have increased to about 0.5 m due to under-estimation of groundwater inflow from an upstream palm plantation. A long-term simulation scenario revealed that the soil salinity and groundwater level have three types of variability in time: a daily variability due to irrigation practices, seasonal fluctuation due to climatic conditions and annual variability explained by the increase in cultivated areas. The irrigation interval was found to be important with irrigating once each ten days leading to soil salinity increase during the dry summer season and to a rising water table during the autumn–winter period. The annual increase in the irrigated area caused a decrease of the irrigation water depths, and thus an augmentation of the soil and groundwater salinities. The surface area affected by a soil salinity concentration above 15 g/L has increased from 2% of the study parcel area in June 1992 to about 50% four years later due to the abandonment of several cultivated basins.

Effect of Chloride and Sulfate Salinity on Micronutrients Release and Uptake from Different Composts Applied on Total Phosphorus Basis

Generation of different biowastes is increasing day by day, and ultimate load on agricultural lands has increased. Concerns over increased phosphorus (P) application with nitrogen (N)–based compost application shifted the trend to P‐based applications. But focus on only one or two nutritional elements will not serve the goals of sustainable agriculture. Full insight into nutrient availability from different composts is necessary. The need to understand the nutrient release and uptake from different composts has increased because of the use of saline irrigation water in the recent scenario of fresh water shortage. Therefore, current greenhouse studies were designed to evaluate the bioavailability and leachability of some micronutrients [calcium (Ca), magnesium (Mg), and zinc (Zn)] from different biocomposts under chloride (Cl−) and sulfate (SO4 −2) saline environment. In the first pot experiment, soil was amended with livestock compost (AC), poultry compost (PC), and composted sludge (SC) at the rate of 200 kg P ha−1 equivalent bases. Pots were irrigated with artificial saline water of sodium chloride (NaCl) or sodium sulfate (Na2SO4; 60 mmolc L−1), and leachates were collected for Ca and Mg analysis. As composts were applied on total P bases, which left varying amounts of nutrients in each treatment, it was observed that nutrient uptake and release differed greatly regardless of the total amount applied with each compost type. Amount of Ca applied with PC (3.9 g pot−1) was greater, but Ca concentration in leachate was greater under AC‐amended treatments. Magnesium concentration also varied greatly under compost types. Among the saline irrigation, Ca and Mg concentration in leachate increased under both saline irrigations compared to nonsaline treatment, and SO4 −2 had relatively greater ionic strength to replace cations than Cl−. Calcium, Mg, and Zn uptake by maize stem and leaves were greater from SC‐amended pots followed by PC, SC, and control. Irrespective of the salt types, Ca and Mg uptake reduced under both saline irrigations, whereas Zn uptake increased as compared to nonsaline treatment. Among the salt types, it was observed that plant growth and nutrient uptake was more influenced by Cl− than SO4 −2 saline irrigation. In the second experiment, soil was saturated with NaCl and NaSO4 (75 mmolc L−1) and amended with AC. The trend of nutrient uptake under both salt types was similar to first experiment, and the results of AC amendments have been discussed. It can be inferred from the results that regardless of the total amount applied, nutrient uptake greatly varies under different composts and their availability depends upon the source rather than total amount applied. Analogously, sulfate‐dominated irrigation water can increase the leaching of Ca and Mg from root zone more than chloride.

Effect of sodium and magnesium on kinetics of potassium release in some calcareous soils of western Iran

The rate of potassium (K) release from soils can significantly influence their K fertility. Sodium (Na), calcium (Ca), and magnesium (Mg) in poor quality (sodic or saline) irrigation water participate in ion-exchange processes resulting in displacement and release of K from minerals into solution. This study determined the effect of sodium adsorption ratio (SAR) and Ca:Mg ratio of water on K release of some calcareous soils in western Iran. Nine different solutions at a total electrolyte concentration of 100 mmol c l − 1 and three levels of SAR (5, 15, 45) each with Ca:Mg ratios of 1:3, 1:1, or 3:1, prepared using solutions of NaCl, CaCl 2, and MgCl 2 were used to extract K from the soils. Significantly different quantities of K were extracted by the solutions. The maximum (average of five soils) (985 mg kg − 1 ) and the minimum (387 mg kg − 1 ) K were extracted by an SAR 5 solution with a Ca:Mg ratio of 1:3 and an SAR 45 solution with Ca:Mg ratio of 3:1, respectively. The importance of Mg versus Ca can be related to the specific ion effect. The kinetics of K release from soils consisted of two phases, an initial rapid phase followed by a slow phase of K release from soils. The two phases of K release are characteristic of a diffusion-controlled process. Based on the correlation coefficients, power function, parabolic diffusion, and Elovich equations adequately described K + release, whereas a first order equation did not. The K release rate for the soils was estimated by parabolic equation from the above solutions. The constant b (mg kg − 1 min − 1/2 ) in the parabolic equation was defined as the release rate and for the Ca:Mg ratio of 1:3 was 96.5 , 55.9, and 35.1.for the SARs of 5, 15, and 45, respectively. The results imply that K extraction from soils could be increased during use of saline irrigation water containing high Mg concentration. The additional K released may be more readily available to plant roots but could also be leached down below the root zone. The results suggest that long-term use of saline irrigation water with a high Mg content could lead to enough leaching of K from soil under saline and sodic conditions that K fertilization management may need modification.

Leachability and Phytoavailability of Nitrogen, Phosphorus, and Potassium from Different Bio‐composts under Chloride‐ and Sulfate‐Dominated Irrigation Water

Concerns over increased phosphorus (P) application with nitrogen (N)-based compost application have shifted the trend to P-based composed application, but focusing on one or two nutritional elements does not serve the goals of sustainable agriculture. The need to understand the nutrient release and uptake from different composts has been further aggravated by the use of saline irrigation water in the recent scenario of fresh water shortage. Therefore, we evaluated the leachability and phytoavailability of P, N, and K from a sandy loam soil amended with animal, poultry, and sludge composts when applied on a total P-equivalent basis (200 kg ha(-1)) under Cl(-) (NaCl)- and SO4(2-) (Na2SO4)-dominated irrigation water. Our results showed that the concentration of dissolved reactive P (DRP) was higher in leachates under SO(4)(2-) than Cl(-) treatments. Compost amendments differed for DRP leaching in the following pattern: sludge > animal > poultry > control. Maize (Zea mays L.) growth and P uptake were severely suppressed under Cl(-) irrigation compared with SO4(2-) and non-saline treatments. All composts were applied on a total P-equivalent basis, but maximum plant (shoot + root) P uptake was observed under sludge compost amendment (73.4 mg DW(-1)), followed by poultry (39.3 mg DW(-1)), animal (15.0 mg DW(-1)), and control (1.2 mg DW(-1)) treatment. Results of this study reveal that irrigation water dominated by SO4(2-) has greater ability to replace/leach P, other anions (NO3(-)), and cations (K+). Variability in P release from different bio-composts applied on a total P-equivalent basis suggested that P availability is highly dependent on compost source.

Yield, Vegetative Growth, and Fiber Length of Kenaf Grown on Saline Soil

AbstractKenaf (Hibiscus cannabinus L.) is an excellent supplement to wood as a source of fiber for paper pulp. With the introduction of kenaf into the western USA, plantings may be on soils where salinity problems already exist or may develop from the use of saline irrigation water. Because of the lack of salt‐tolerance information on mature vegetative growth and yield, a 2‐yr field‐plot study was conducted at Brawley, CA. Two cultivars (Everglades‐41 and 7818‐RS‐10) were grown with six salinity treatments imposed on a Holtville silty clay [clayey over loamy, montmorillonitic (calcareous), hyperthermic Typic Torrifluvent]. Electrical conductivities of the irrigation waters, containing NaCl and CaCl2 (1:1 by weight), were 1.1, 2.0, 3.0, 4.0, 5.0, and 6.0 dS m−1. Soil salinity (electrical conductivity of the saturated‐soil extract, Kc) ranged from 5.4 to 12.6 dS m−1 the first year, and from 6.0 to 14.9 dS m−1 the second year. Vegetative growth, stem yield, and fiber length were measured. The mean dry weight yields of the stems during the 2‐yr experiment were reduced 11.6% for each unit increase in soil salinity above 8.1 dS m−1. These results place kenaf in the salt tolerant category. Yield reduction resulted from both a reduction in plant height and stem diameter. Increased salinity did not significantly affect fiber length. Excessive Cl accumulation occurred in the leaf tissues at high soil salinity levels.

TOMATO FRUIT QUALITY AND ION STATUS: THE EFFECTS OF SALINITY, PHYTOPHTHORA ROOT ROT AND GENOTYPE

Tomato Fruit quality can be improved by the use of moderately saline irrigation water. However, decreased fruit yields may occur if the saline treatment is initiated early in plant development or the salt concentration is high. Another concern with the use of saline irrigation water is increased plant susceptibility to disease. Two processing tomato cultivars were grown under low salt (ECa=1.1 ds/m), medium salt (ECa=2.8 ds/m) and high salt (ECa=4.6 ds/m) regimes, and in the presence and absence of Phytophthora parasitica, the casual agent of Phytophthora root rot. Salinity increased Phytophthora root rot severity in UC82B, the susceptible cultivar, but had a limited effect on CX8303, a cultivar known to have a measure of resistance to Phytophthora root rot. Fruit acidity and percent total soluble solids were enhanced in both cultivars by increasing salinity. Infection by P. parasitica increased acidity and soluble solids in UC82B fruit grown under high salt. Sodium and chloride concentrations in tomato fruit increased in a manner proportionate to the salt treatment applied; however, in the absence of disease, fruit Na+ and Cllevels were markedly lower compared to other tissues in the plant, The presence of salt-enhanced Phytophthora root rot in UC82B increased fruit Na+ concentration by almost 100%. Fruit Ca2+ and K+ levels, in contrast, declined moderately with increasing salinity and were not affected by disease.

Corn production as influenced by irrigation and salinity ? Utah studies

This paper reports the results of a two-year field study at Logan, Utah which was one of a series of similar experiments carried out at Ft. Collins, Colorado, Davis, California and Yuma, Arizona. A range of water application rates were imposed using the line-source system (Hanks et al., 1976) and in some treatments water was withheld during certain growth stages. Salinity variables were imposed by presalinization before planting and by the use of saline irrigation water. Regardless of irrigation or salinity regime, corn grain and total dry matter production were linearly related to evapotranspiration, which was measured as the sum of irrigation, rainfall and soil water depletion minus drainage. Presalinization of the soil decreased yields in proportion to the salinity imposed, the decrease being associated with reductions in evapotranspiration caused by reduced soil water depletion as compared to the nonsalinized treatments.