Increasing Salinity Of Irrigation Water Research Articles

Desenvolvimento e qualidade de frutos de melão amarelo sob estresse salino

ABSTRACT The need for studies that allow the use of brackish water in irrigated agriculture and the socioeconomic importance of melon cultivation in Brazil, especially for the Northeast region, which concentrates most of the national production and faces problems with the availability of good quality water for irrigation, motivated the present study. In this context, the objective of present study was to evaluate the growth, production and fruit quality of the ‘Goldex’ (yellow-type hybrid F1) melon under salt stress conditions. The experiment was performed in a completely randomized design, with two salinity levels of irrigation water (0.8 and 4.0 dS m-1) and eight evaluation times (52, 54, 56, 58, 60, 62, 64, and 66 days after transplanting). Variables of plant growth and development, production and quality of melon fruits were evaluated throughout the cycle. Plants had delayed growth characteristics and less development with the increase in irrigation water salinity, showing reductions of more than 20% in shoot dry weight, leaf area, number of branches and length of secondary branches and 16.7% in length of the main branch. In addition, salinity caused a delay in fruit development and a 16% reduction in final fruit weight, without significantly modifying carbohydrate and total soluble solids contents. Along the development, there was an increase in the total soluble solids content of the fruits, especially due to the increment of sucrose at the final stages of development.

Soil salinity and nutrient availability influenced by silicon application to tomato irrigation with different saline water

Silicon can be used as a soil amendment to reduce deleterious soil salinity and improve nutrient availability under different irrigation water salinity levels. Four treatments of Si (0,150 and 300 kg Si ha-1 as nano-silica and 300 kg Si ha-1 as potassium silicate) along with four salinity levels of irrigation water (1.65,3,6and 9 dSm-1 ) were used to investigate their effect on soil salinity at three soil depth ( 0-15, 15-30 and 30-45 cm ) and availability of N, P and K in soil cultivated with tomato. The experiment was conducted under greenhouse conditions using a random complete block design with three replicates. According to the results, increasing irrigation water salinity level increased soil salinity and decreased available N, P and K to tomatoes. Si treatments decreased soil salinity and increased available amounts of N, P and K . Using 300 Kg Si ha-1 of nano-silica caused the lowest soil salinity of 1.89, 2.51 and 3.23 dSm-1 for 0-15, 15-30, and 30-45cm depth, respectively and increased availability of N, P and K with a percent of 19.4, 14.1 and 82.7 %, respectively. Keywords: nano-silica, soil salinity, available nitrogen, irrigation water salinity, tomato.

Examining the Effects of Biochar in Spinach Cultivation with Increased Irrigation Water Salinity on Some Physical and Physiological Properties of the Plant

The inadequacy of fresh water resources in today's conditions has revealed the use of salty water as an alternative water source in agricultural irrigation but salinity, which is shown as the most important source of abiotic stress, increases osmotic stress and decreases the water intake of the plant, resulting in a physiological drought. For this reason, there is a need for applications to improve the decreasing efficiency in the use of salt water in irrigation through different practical and economic approaches. This study investigating the effects of biochar application into the soil against irrigation water salinity in spinach cultivation on some physical and physiological properties of the plant was carried out in five-liter pots in greenhouse conditions, in a completely randomized factorial experimental design with three replications, in three different irrigation water salinity levels with NaCl salt source [I0: tap water; 0.4 (control), I1: 2.5, I2: 5 dS m-1] and three different biochar dosage based on weight [B0: 0 (control), B1: 1.5, B2: 3%] conditions. As a result of the study, plant height, leaf number and area, shoot wet weight from physical properties and chlorophyll and leaf relative water contents from physiological properties decreased with increasing irrigation water salinity levels but the membrane damage decreased, while the physical and physiological properties of spinach increased with the increasing mixing ratio of biochar to the soil, excluding membrane damage. It was found that the use of biochar against irrigation water salinity can be recommended considering that mixing biochar to the soil against irrigation water salinity in spinach cultivation regulates the physical and physiological properties of the plant but to obtain more comprehensive information on this subject, evaluation of different irrigation water salinity and biochar ratios in terms of field studies has emerged as a recommendable result.

Purslane (Portulaca oleracea L.) salt tolerance assessment

ABSTRACT The present study was aimed to evaluate the effect of irrigation water salinity on some agronomic and physiological attributes of purslane (Portulaca oleracea L.) and its tolerance to salinity stress. The treatments included seven levels of electrical conductivity of irrigation water (0.6 (control), 3, 6, 9, 12, 15, and 18 dSm−1) arranged in the form of a completely randomized design with three replications. The results showed that salinity stress successively decreased agronomic attributes such as root, shoot, and stem dry weight, plant height and leaf area. Physiological attributes such as relative water content as well as ion leakage differently responded to salinity stress. Relative water content response to salinity followed a quadratic regression model with the maximum of 81% at electrical conductivity of 6.87 dSm−1 and the minimum of 65% at highest salinity level of 18 dSm−1. Following an exponential regression model, ion leakage remained relatively the same till irrigation water salinity of 15 dSm−1 and reached to the maximum of 78% at highest irrigation water salinity of 18 dSm−1. In addition, shoot potassium content of purslane under non saline conditions equaled to 11% that was around 10 times more than the typical of potassium sufficient concentration for adequate growth. Moreover, with increasing salinity stress, shoot potassium content decreased to 7% at highest salinity level of 18 dSm−1 of irrigation water. However, with increasing irrigation water salinity, sodium shoot content of purslane was increased from 1.9% at the lowest salinity stress to 6.7% at the highest salinity stress. Based on the linear and nonlinear models, 10% of purslane biomass reduction occurred at soil electrical conductivity of around 10 dSm−1. In addition, 25 and 50% yield reduction observed at 16 and 25 dSm−1 of electrical conductivity of soil saturated paste. Therefore, purslane can be considered as a very salt tolerant plant, halophyte, and can successfully grow in soils with electrical conductivities not suitable for most crops.

The Effect of Polymeric Hydrogel Application on Germination Under Saline Irrigation Water: Case Study of Barley

In recent years, it has been tried to increase the usage areas of polymeric hydrogels, which are used to increase the water holding capacity of light textured soils in agricultural production. In this study, the effects of polymeric hydrogel on the germination of barley seeds under low quality irrigation water conditions were investigated. For this purpose, irrigation water prepared with an Electrical Conductivity (ECi) value of 0 [control], 6, 8, and 12 dS m-1 and Sodium Absorption Rate (SAR) less than 3 is placed in petri dishes in which 0.01 grams hydrogel has been added. 10 seeds of barley (Hordeum vulgare conv. distichon) variety were added to the same petri dishes. According to the results of variance analysis made with the data obtained in the study, it was determined that increasing irrigation water salinity was effective at the 5% significance level on the germination rate and seedling dry weight of barley. However, the difference between the subjects treated with hydrogel was not statistically significant. In response to the increased irrigation water ECi value, the germination rate and germination power of barley decreased. It was determined that hydrogel application did not have any effect on the germination rate and germination power of barley under increasing ECi value conditions.

The optimal irrigation water salinity and salt component for high-yield and good-quality of tomato in Ningxia

Although saline water can be used as an alternative of freshwater resources for agricultural irrigation, especially in arid and semiarid areas, however, unsuitable saline water quality and unreasonable irrigation technology may result in the detrimental effects on plant growth, yield and quality of products. Thus, a three-year open field experiment was conducted in Ningxia to investigate the influence of three irrigation water salinity levels (1, 2 and 3 g/L) and five molar concentration ratios (MCR) of Na:Ca (1, 3, 5, 7 and 9) on processing tomato planting, in terms of crop water consumption, tomato yield traits and fruit quality characteristics. The results are as follow: (i) The water consumption decreased significantly with the increasing irrigation water salinity and MCR of Na:Ca. (ii) With the increase of irrigation water MCR of Na:Ca, both the average fruit weight, marketable yield and total yield decreased linearly, as well, the ratio of marketable yield to total yield decreased. Additionally, irrigation water with higher salinity (2 g/L and 3 g/L) and lower MCR of Na:Ca (1 and 3) was more conducive to root water uptake and average fruit weight accumulation, than that with lower salinity and higher MCR of Na:Ca. (iii) With irrigation water salinity of 1 g/L and 2 g/L, both the vitamin C, lycopene, fructose, sucrose and starch content of tomato fruit have quadratic function relationship with the irrigation water MCR of Na:Ca. Moreover, the threshold of irrigation water MCR of Na:Ca for soluble solids, lycopene and starch accumulation was 7, while the content of total soluble sugar, fructose and sucrose achieved the maximum value as the MCR of Na:Ca arrived 5. (iv) With irrigation water salinity of 3 g/L, the total soluble sugar and glucose of fruit decreased with the increase of irrigation water MCR of Na:Ca, especially, the fruit fructose, sucrose and starch concentration decreased linearly, furthermore, the threshold of irrigation water MCR of Na:Ca for vitamin C and soluble solids accumulation was 5. Synthetically, saline water with salt content of 2 g/L and MCR of Na:Ca at 5 was optimal in the present study for mulched drip irrigation on tomato cultivation in the northern Yinchuan plain of Ningxia, obtaining the relatively high-yield (9.72 ×104 kg/hm2) and good-quality of tomato.

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.

Effects of Applied Biochar and Municipal Solid Waste Compost on Saline Soil Properties and Sorghum Plant Attributes

The hypothesis is that incorporating saline soil with biochar or compost reduces the deteriorating effects of salinity. The pot experiment was irrigated with waters with different salinities (4.5 and 9 dS m-1) and a silty clay soil in pots was thoroughly mixed with 1.5% w/w of biochar, 1.5% w/w of municipal solid waste compost and the mixtures of 0.5 × 0.5% w/w of the two mentioned substances. Irrigation was provided to realize 0.15 leaching fractions for equilibrating the soil salinity. Soil and plants were analysed after two months (T1) and three months (T2) after sowing. Saline irrigation water decreased SAR (~45%) and SOC (~5.5%), respectively for T2 compared with T1. The biochar treatment reduced the amount of ECe in T1 and T2. Both irrigating with saline water and amendments greatly changed the amount of leaf water potential (LWP), chlorophyll and proline leaf. LWP and proline were increased by 17 and 76%, respectively, with increasing irrigation water salinity, while the leaf chlorophyll content was significantly decreased (~52%). The overall finding was that incorporating the saline soil of the region with biochar showed more potential to enhance soil properties and sorghum production.

Effects of Applied Biochar and Municipal Solid Waste Compost on Saline Soil Properties and Sorghum Plant Attributes

The hypothesis is that incorporating saline soil with biochar or compost reduces the deteriorating effects of salinity. The pot experiment was irrigated with waters with different salinities (4.5 and 9 dS m-1) and a silty clay soil in pots was thoroughly mixed with 1.5% w/w of biochar, 1.5% w/w of municipal solid waste compost and the mixtures of 0.5 × 0.5% w/w of the two mentioned substances. Irrigation was provided to realize 0.15 leaching fractions for equilibrating the soil salinity. Soil and plants were analysed after two months (T1) and three months (T2) after sowing. Saline irrigation water decreased SAR (~45%) and SOC (~5.5%), respectively for T2 compared with T1. The biochar treatment reduced the amount of ECe in T1 and T2. Both irrigating with saline water and amendments greatly changed the amount of leaf water potential (LWP), chlorophyll and proline leaf. LWP and proline were increased by 17 and 76%, respectively, with increasing irrigation water salinity, while the leaf chlorophyll content was significantly decreased (~52%). The overall finding was that incorporating the saline soil of the region with biochar showed more potential to enhance soil properties and sorghum production.

Mitigation adverse effects of salinity stress on wheat plants by co-inoculation of plant growth promoting rhizobacteria, arbuscular mycorrhizal fungi and compost amendment

Salinity has become one of the most important challenges in agriculture. A pot experiment was conducted during 2017/2018 and 2018/2019 seasons at the greenhouse of Fac. Agric., Cairo Univ., Giza, Egypt, on Triticum aestivum L., var. Gemmiza 10. Plants irrigated with diluted seawater with tap water (control), 4.0 6.0, 8.0 and 10.0 dS m-1 to investigate the utilization of co-inoculation of plant growth promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) and the addition of compost individually or in combination as an environmentally sustainable tools to alleviate the effects of salinity on wheat plants at both 75 days after sowing (DAS) (elongation stage) and 150 DAS (maturity stage). Salinity stress caused significant reduction in shoot height, shoot fresh and dry weights, K+/Na+ ratio and nitrogen, phosphorous and potassium contents of shoot at 75 DAS, however, Na+ concentration increased significantly. At maturity yield and its attributes, nitrogen, phosphorous and potassium contents in grain and straw decreased significantly with increasing irrigation water salinity level. Co-inoculation and/or compost amendments increased significantly the growth parameters and yield components compared to untreated plants under all irrigation water salinity levels.

Does Phosphorus Fertilization Increase Biomass Production and Salinity Tolerance of Blue Panicum (Panicum antidotale Retz.) in the Salt-Affected Soils of Arid Regions?

High soil salinity, drought, and poor soil fertility, especially phosphorus (P) deficiency, are serious challenges for crop production in arid and desert climate regions. In these regions, irrigation water (mostly groundwater) is saline, and fertilization is one of the strategies used to cope with salinity stress. Crop livestock is one of the major agricultural activities in marginal regions, and blue panicum (Panicum antidotale Retz.), the perennial forage grass, has the potential to furnish forage demand. Thus, a field experiment testing the combination of three levels of irrigation water salinity and three P rate was carried out to evaluate the potential of P fertilizer to enhance yield and salinity tolerance of blue panicum grass. The experiment was conducted for two years between 2019 and 2020 in Foum el Oued, Laayoune, Morocco. It was implemented in a split-plot design with three replications considering irrigation water salinity as the main plot and P rates as sub-plot treatments. The evaluated P rates were 0, 90, and 108 kg P2O5 ha−1 (P1, P2, and P3, respectively), and the irrigation water salinities were 5, 12, and 17 dS·m−1. The results revealed that increasing irrigation water salinity significantly decreased the biomass production and stomatal conductance of blue panicum. Increasing irrigation water salinity from 5 to 12 and 17 dS·m−1 decreased fresh biomass production by 20 and 29%, respectively. Irrigation water salinity also decreased (p < 0.05) leaf N, P, K, Ca, and Zn concentration. However, supplementation of P fertilization enhanced (p < 0.05) biomass production and stomatal conductance mainly by improving leaf OM, Zn, and Fe content. P fertilization at 108 kg P2O5 ha−1 increased fresh biomass by 27%, 32%, and 19% under 5, 12, and 17 dS·m−1, respectively. Considering increased fresh biomass yield, P application at the rate of 108 kg P2O5 ha−1 can be suggested for saline drylands. P application is recommended to reduce the adverse effects of high salinity on growth and productivity and improve salinity tolerance of blue panicum in salt-affected arid and desert regions.

Effects of saline water mulched drip irrigation on cotton yield and soil quality in the North China Plain

The shortage of freshwater resources is a considerable challenge for agricultural production in the North China Plain (NCP). Safe and efficient use of saline water resources is thus urgently required. To reveal the effects of different salinities of irrigation water on the yield and soil quality of mulched drip-irrigated cotton, a field experiment was conducted from 2017 to 2019. Five salinity levels of irrigation water were included: 1.3 (T1, control), 5.4 (T2), 8.8 (T3), 12.4 (T4) and 15.9 (T5) dS·m−1. The results showed that the harvesting density and seed cotton yield increased first and then decreased with increasing salinity of irrigation water. Saline water irrigation with salinity ≤ 8.8 dS·m−1 did not lead to salt accumulation in the main root zone (0–60 cm) with each passing year but a decrease of salt in 2018. In the third year of saline water irrigation, with the increase in irrigation water salinity, the electrical conductivity of the saturated soil extract (ECe), soil sodium adsorption ratio (SAR), pH and bulk density (BD) in the plow layer gradually increased. However, the soil saturated hydraulic conductivity (Ks), water stable macroaggregate (> 0.25 mm) content, catalase (CAT) and urease (URE) activity decreased with increasing salinity. Moreover, the soil organic carbon (SOC) content and alkaline phosphatase (ALP) activity increased first and then decreased. Irrigation water salinity ≤ 5.4 dS·m−1 had no significant effect on most physicochemical properties, such as pH, SOC content, BD, Ks, water stable aggregate content and activities of CAT, URE and ALP. Compared with the T1 treatment, the soil quality index (SQI) of T2, T3, T4 and T5 treatments decreased by 1.2%, 10.5%, 16.5% and 23.7%, respectively. Considering cotton yield, soil salt accumulation and SQI, mulched drip irrigation is conducive to the sustainability of cotton with saline water levels below 5.4 dS·m−1.

Brackish groundwater and reverse osmosis concentrate influence soil physical and thermal properties and pecan evapotranspiration

AbstractThe use of brackish groundwater (BGW) to supplement irrigation shortfalls has increased because of decreasing surface water availability in the arid areas of the southern United States. Reuse of reverse osmosis (RO) concentrate, a by‐product resulting from desalination of BGW, can increase irrigation portfolio. This 2‐yr greenhouse study aimed to quantify changes in physical and thermal soil properties, and evapotranspiration (ET) rate of pecan [Carya illinoinensis (Wangenh.) K. Koch] irrigated with BGW and RO concentrate. Another objective was to predict soil thermal conductivity (K) using soil electrical conductivity (EC) and soil volumetric water content (VWC) data of 2017–2018. Three irrigation water treatments with four replications were prepared namely, control (EC = 0.8 dS m−1), BGW (EC = 4.0 dS m−1), and RO concentrate (EC = 8.0 dS m−1). Soil physical properties determined were texture, moisture content, bulk density, hydraulic conductivity, and moisture retention. Thermal properties measured were conductivity (K), diffusivity (D), resistivity (ρ), and heat capacity (C). The ET and leaching fractions (LF) were determined using water balance. Pecan irrigated with RO concentrate had the lowest ET among irrigation treatments. Soil thermal conductivities and soil water contents in BGW and RO irrigated pots were higher than the control. However, increases in heat capacity with increasing irrigation water salinity were most pronounced. The new four parameters‐based model using EC and VWC explained 96% of variability of K (average R2 = .96, RMSE = 0.096, normalized RMSE [NRMSE] = 11.14%). The sensitivity analysis showed that the contribution of VWC to K was greater than that of EC. Results indicate that continuous irrigation with RO concentrate can be done for up to 1 yr. A new irrigation scheduling protocol based on optimal LF and soil salinity is needed to sustain pecan production in southern New Mexico.

Foliar application of H2O2 as salt stress attenuator in ‘BRS Rubi do Cerrado’ sour passion fruit

Irrigation with saline water causes a reduction in yield, especially in semi-arid regions. Cultivation strategies have been developed to mitigate salt stress on plants, such as the use of hydrogen peroxide. The objective of this study was to evaluate the attenuating effect of hydrogen peroxide on the gas exchange and growth of ‘BRS Rubi do Cerrado’ sour passion fruit cultivated under irrigation with saline water. The design was completely randomized in split-plot plots, with water salinity levels ECw (0.6, 1.2, 1.8, 2.4, and 3.0 dS m-1) considered the plots and the concentrations of hydrogen peroxide H2O2 (0, 15, 30, and 45 μM) considered the subplots, with three replicates. Gas exchange (stomatal conductance, transpiration, CO2 assimilation rate, intercellular CO2 concentration, instantaneous water use efficiency, and instantaneous carboxylation efficiency), and absolute and relative growth rates in stem diameter were evaluated. An increase in irrigation water salinity from 0.6 dS m-1 reduced gas exchange, and exogenous application of hydrogen peroxide did not promote a significant effect on gas exchange. However, foliar application of hydrogen peroxide at 15 μM increased the growth of ‘BRS Rubi do Cerrado’ sour passion fruit.

Response of malt barley grain quality characteristics to increasing irrigation water salinity

Premiums are offered for high quality grain, but producers of malting barley are often confronted with marginal soils and water scarcity. Irrigation water quality is often low, primarily due to high salt loads. This study determined the effect of irrigation water salinity (ECi) on grain quality characteristics of malt barley evaluated in a lysimeter-based trial over two seasons. The trial involved five ECi levels (1. 5, 4. 5, 6, 9 and 12 dS m−1), and two different soil types (Bainsvlei and Clovelly). Grain yields, 1 000 seed mass (TSM, g), germination characteristics, and crude proteins (CP) were determined. Salinity levels of greater than 6 dS m−1 decreased TSM but had no significant effect on germination characteristics, while CP content of the grains significantly increased above the required range (between 9% and 11.5%) for malting. Increasing ECi reduced malt extract potential for all treatments, most noticeably at 9 and 12 ECi dS m−1. There were significant relationships between salinity and germinative characteristics as well as the malt extract proxy (germination index). The study shows that premium quality barley grain cannot be produced when salinity exceeds 6 dS m−1 and that the Clovelly soil would be a better fit for producing barley irrigated with saline water.

Production of Pityrocarpa moniliformis (Benth.) Luckow & R.W. Jobson (Fabaceae) seedlings irrigated with saline water

ABSTRACT Saline irrigation water at high levels causes disturbance in the growth of more sensitive plants. The objective of this research was to evaluate the initial growth of Pityrocarpa moniliformis seedlings under different electrical conductivity in irrigation water through physiological and biochemical analyses. The experiment was conducted in a greenhouse with five water electrical conductivities (0.5, 2.0, 4.0, 6.0 and 8.0 dS m-1) and four repetitions of 20 plants each, arranged in a randomized block design. Application of the treatments with irrigation water containing NaCl began at 30 days after sowing. To determine the behaviour of the species, the following variables were analysed: stem diameter, plant height, number of leaves, leaf area, Dickson quality index, shoot dry mass, root dry mass and total dry mass, as well as the biochemical variables, such as the concentrations of total soluble sugars, free proline and chlorophylls a and b. The increase in irrigation water salinity hampered the growth of P. moniliformis seedlings, with electrical conductivity of 0.5 dS m-1 being the limit for maximum production. The results also indicated that the deleterious effects of salt stress on P. moniliformis seedlings variables increase in concentrations of proline, total soluble sugars and betaine glycine.

Effect of Irrigation Water Salinity and Deficit Irrigation on Soil Ions Variation and Uptake by Saffron (Crocus sativus L.) Under Two Planting Methods

A 2-years field experiment in a split-split plot arrangement was considered to investigate the effects of different irrigation water salinity [0.45 (well water, S1), 1.0 (S2), 2.0 (S3), 3.0 (S4) dS m−1], irrigation water levels [100% (I1), 75% (I2) and 50% (I3) of saffron water requirement (WR)] and planting methods [basin (P1) and in-furrow (P2)] on the dynamics of salt ions and their uptake by saffron plant (Crocus sativus L.). The electrical conductivity of soil saturation extract (ECe) was increased by 104% in S4 compared to control (S1), on average, in two growing seasons. S4 treatment increased concentration of sodium (Na+), calcium (Ca2+), potassium (K+) and chloride (Cl−) in soil by 102%, 92%, 124% and 128% in comparison with S1, on average, in two growing seasons. The concentration of Na+, Ca2+, K+ and Cl− in soil in S4 were 30%, 15%, 28% and 29% higher and NO3 was 30.3% lower in I1 in comparison with I3, respectively. The ions concentration in soil were 3.5–14.7% higher in P1 in comparison with those in P2. Leaf Na+, Ca2+ and Cl− concentration was increased by increase in irrigation water salinity while K+, nitrogen (N) and phosphorus (P) concentrations were decreased by 28.4%, 25.7% and 29.8% in S4 in comparison with that obtained in S1, on average, which is presumably due to reduced NO3 and P concentrations in soil and increased Na+ uptake by saffron. Also, deficit irrigation reduced soil and leaf ions (Na+ and Cl−) threshold and increased the slope of relative yield-ions concentration reduction function, which indicated that water stress aggravates saffron sensitivity to salinity and ions concentration in soil and leaf. Results indicated that saffron was more sensitive to Na+ concentration in soil extract compared with Cl−. Na+ and Cl− threshold was 19.3% and 27.1% higher in P2, on average, in different irrigation levels, respectively. Therefore, the in-furrow planting method is suggested to cope with unfavorable saffron field conditions.

Growth of Phaseolus vulgaris on brackish ground water using sub-surface membrane irrigation under variable climatic conditions

A subsurface membrane irrigation was used to germinate and cultivate seedlings of Phaseolus vulgaris (common beans) on brackish water under variable climatic conditions. Changes in the air vapour pressure deficit (VPD), representative of increased accumulative evaporative demand between autumn and summer, from 14.8 to 21.5 kPa over a 15 day growth period, resulted in an increase average daily water uptake of 1.4 to 2.5 mm/d. Increasing irrigation water salinity from 0.2 dS/m to 1.4 dS/m and 1.4 dS/m to 3.1 dS/m reduced initial water uptake by a factor of 1.8 and 3.1 respectively indicating an imposed osmotic resistance due to salt retention. Plant water uptake after the establishment of a root network at 15 days after sowing was 36% higher for irrigation systems configured from the reverse osmosis (RO) membrane (flux 1.5 mm/d) compared to the forward osmosis (FO) at a salinity of 0.2 dS/m. The observed differences in flux can be attributed to distinct resistances imposed by the two membrane structures on water transport, although scanning electron microscopy (SEM) images also suggest an effect of membrane type on root structural development. More importantly, the use of both FO and RO resulted in a reduction of soil salt accumulation by 40% at the highest salinity of 3.1 dS/m, which reduced the projected decline in bean yield of 22.2% per dS/m to 5.6% per dS/m. This corresponds to an average increase in yield potential of 40% for cultivation of beans on irrigation water with a salinity of 3.1 dS/m. The paper demonstrates that subsurface membrane irrigation has the potential to accommodate the use of brackish water in a warmer and drier climate without compromising yield and exacerbating soil salinization.

Fisiologia e fitomassa de porta-enxerto de cajueiro sob águas salinizadas e adubação orgânica

O uso de águas salinas na agricultura tornou-se uma alternativa em diversas regiões do mundo, contudo é necessário o desenvolvimento de técnicas para viabilizar o uso dessas águas na agricultura. Diante do exposto, objetivou-se avaliar o efeito da salinidade da água de irrigação sob as respostas fisiológicas e produção de fitomassa de porta-enxerto de cajueiro anão precoce CCP 06 associado a doses crescentes de matéria orgânica, em experimento conduzido em condições de ambiente protegido do Centro de Ciências e Tecnologia Agroalimentar da Universidade Federal de Campina Grande (CCTA/UFCG), Campus de Pombal (PB). Utilizou-se o delineamento experimental de blocos casualizados, em esquema fatorial 5 x 4, com 3 repetições e duas plantas por parcela, sendo os tratamentos compostos de cinco níveis de condutividade elétrica da água (0,3; 1,0; 1,7; 2,4; e 3,1 dS m-1) e quatro doses de matéria orgânica (2,5; 3,5; 4,5; e 5,5% em base do volume de solo). A salinidade da água de irrigação de até 0,90 dS m-1 proporciona perdas aceitáveis de 10% na transpiração, condutância estomática e a fotossíntese líquida dos porta-enxerto de cajueiro CCP 06. A dose de MO de 2,5% proporcionou maior produção de massa seca do caule sobre o de porta-enxerto de cajueiro CCP 06 durante o período de execução do trabalho. O aumento da salinidade na água de irrigação causa os efeitos deletérios sobre a massa seca de folha, caule e raiz em ambos os períodos estudados.

Sulama Suyu Tuzluluğunun Sakız Fasulyesinin Bazı Bitkisel Özelliklerine Etkisi

Çalışma, guarın (Cyamopsis tetragonoloba (L.) Taub.) sulama suyu tuzluluğuna olan hassasiyetini belirlemek amacıyla saksılarda, sera koşullarında yürütülmüştür. Çalışma bölünmüş parseller deneme desenine göre 3 tekerrürlü olacak şekilde gerçekleştirilmiştir. Çalışmada 8 guar genotipi materyal olarak kullanılmıştır. Sulama suyu olarak SAR değeri 3’den düşük olacak şekilde elektriksel iletkenlik değerleri (ECi) 0.35, 5, 15 ve 30 dS m-1 olan tuzlu sulama suları kullanılmıştır. Artan sulama suyu tuzluluğu bitkilerde olumsuzluklara neden olmuştur. Saksı başına tane verimi 1.39-10.39 gram ve bitki boyu 18.61-80.68 cm arasında değişim göstermiştir. Artan sulama suyu tuzluluğu bitki kök bölgesi tuzluluğunda artışa neden olmuştur. Bitki kök bölgesindeki toprak tuzluluğu (ECe) değerleri 0.67-53.16 dS m-1 arasında değişim göstermiştir.