Salt Concentration In Irrigation Water Research Articles

Tolerance and Adaptability of Tomato Genotypes to Saline Irrigation

High salt concentration in irrigation water is often a limiting factor to tomato production in Brazil. However, there is limited information available regarding the tolerance of tomato genotypes to saline irrigation. An experiment was conducted in a protected environment using a randomized block design with four replications. Treatments consisted of 12 tomato genotypes cultivated in an environment with varying levels of salt stress. Moderate and severe salt stress affected plant height, transversal and longitudinal diameter of fruit, fresh mass, yield, and number of tomato fruit per plant. Cluster analysis, stability, and adaptability provided the best estimates to identify the most adaptable genotype to saline stress, with the genotypes Maestrina, Onix, Pizzadoro, and Shanty being the best adapted to moderate and severe saline stress conditions. The genotypes Maestrina, Onix, Pizzadoro, and Shanty were identified as most adaptable to and stable under salt stress. Sodium absorption increased as irrigation salinity increased. In addition, P, K, and Ca concentration decreased under salt stress, which caused damage to all yield components and plant nutrition. The genotype Onix was more tolerant to the effects of moderate saline irrigation, while the genotypes Sheena, Sperare, Santa Clara, IPA 6, and Dominador had lower losses under severe salt stress conditions.

Drip Irrigation as a Potential Alternative to Traditional Irrigation Method for Saline Water Usage in Vegetable Crops- A Review

The aim of this review was to understand the response of various vegetable crops to different salinity and nitrogen levels under drip and traditional methods of irrigation. Effective methods of irrigation water application are important that would allow the proper use of poor-quality water for sustainable production. Drip irrigation is an economically feasible technology for water-saving (40%) and increasing the yield (30−40%) in different crops. Various research studies found that the salt concentration of irrigation water was negatively correlated with growth, fruit yield and quality parameters of vegetable crops. Further, the plants which received 100% of recommended dose of fertigation under saline water irrigation showed a better performance in terms of higher nutrient uptake of nitrogen (150.09−226.26 kg ha-1), phosphorous (13.67−74.64 kg ha-1), and potassium (155.70−302.05 kg ha-1) with highest water use efficiency (11.9−61.68 kg ha-1 m-1). We made an attempt to review and compile the ill effects of saline water application and also summarise management strategies to manage poor quality water in vegetable production, especially in arid and semi-arid regions. The review also highlighted the importance of drip irrigation as an alternative to conventional methods for efficient use of poor-quality water without adversely affecting the quality and productivity of vegetable crops.

Organic fertigation system in saline‐sodic soils: A new paradigm for the restoration of soil health

AbstractA continuous decline in soil organic C (SOC) and an increase in salt‐affected areas are a challenge to future sustainability. We searched on the scientific databases of Web of Science, Scopus (Elsevier) database, and Google. We reviewed 101 studies of the last 25 yr with the following keywords: drip irrigation, fertigation system, liquid biochar, liquid organic, organic fertigation, saline‐sodic soils, and salinization. Our objectives were to identify knowledge gaps to direct future organic research and assess the effect of organic amendments on meeting the plant's N, P, and K requirements in saline‐sodic soils. The review showed that organic fertigation systems reduce salt concentration in irrigation water and inhibit glutamine synthetase by N‐fixing diazotrophs. The system increases photosynthetic activities in plants, microbial biomass C, bacterial colonization, plant–mycorrhizal association, and phospholipid‐derived fatty acids from microbes. It increases essential soil nutrients, including SOC; increases salt/water stress tolerance; and reduces Na+ ion toxicity in plants by regulating abscisic acid pathways in saline‐sodic soils. It creates a conducive environment for phosphatase, dehydrogenase, urease, protease, α‐amylase, and gibberellins. This review sketches the role of silicic acid, salicylic acid, and liquid organics in plant growth mechanisms: enhanced photosynthesis, increased salt/water tolerance, and reduced Na+ toxicity. It suggests novel strategies to develop a task force to promote a community–corporate farming system to adopt cost‐effective green technologies for bioresource regeneration, diverse market production, and social capital generation. We develop a synergy between organic fertigation system and community–corporate farming to bring much‐needed agricultural sustainability.

Growth and yield of beet irrigated with saline water in different types of vegetable mulching

ABSTRACT Vegetal mulching can mitigate the harmful effects of salts present in irrigation water. This study aimed to evaluate the effect of irrigation water salinity and mulching on the growth and yield of beet crops. The experiment was conducted in a greenhouse at Redenção, Ceará State. The experimental design was completely randomized in a 2 × 4 factorial scheme, with five replicates, composed of two levels of electrical conductivity of irrigation water - ECw: tap water - 0.3 dS m-1 and saline solution - 5.8 dS m-1; and four types of mulching (rice hulls, carnauba bagana, crop residues, and a control treatment without soil cover). The use of vegetal mulching, mitigated the effects of irrigation with saline water on the variables plant height, leaf area, stem diameter, and tuberous root. The increase of the salt concentration in irrigation water negatively affected the number of leaves, length of the tuberous root, and yield. But, it increased the soluble solids in the beet crop.

Growth response of blue panic grass (Panicum antidotale) to saline water irrigation and compost applications

ABSTRACT A pot experiment was conducted to examine the ability of Blue Panic grass (Panicum antidotale) to grow in slightly saline soils (2.40 dS m–1) under different levels of saline irrigation water in the presence or absence of compost. Eight treatments were set up in a randomized block design with five replicates as follows: T1 (Freshwater), T2 (Freshwater + compost at 20%), T3 (Saline water 5000 mg L–1), T4 (T3 + compost at 20%), T5 (Saline water 10000 mg L–1), T6 (T5 + compost at 20%), T7 (Saline water 15000 mg L–1) and T8 (T7 + compost at 20%). Growth parameters of Blue Panic Grass were evaluated at the end of the experimental period as plant and root length, shoot, and root fresh and dry weights, total chlorophyll, and total carbohydrates. In general, tested Blue Panic Grass appeared to be tolerant to high salt concentrations in irrigation water, and slightly significant differences were found for all the measured parameters. A remarkable growth increase occurred in plants grown in compost-amended soils, with respect to the unamended soils. The results demonstrate the possibility to stabilize the yield of blue panic grass, an important feed crop in Egypt, irrigated with saline water, which can secure animal feed resources without reducing the already limited freshwater availability.

Physiological changes and growth of soursop plants under irrigation with saline water and H2O2 in post-grafting phase

The low availability of water associated with high salt concentrations in irrigation water has become one of the leading challenges for agricultural production in the semiarid region of Northeastern Brazil. Thus, the study of strategies to enable the use of saline water in agriculture is essential. From this perspective, this study aimed to evaluate alterations in gas exchange, chloroplast pigments, and cell damage in soursop (Anonna muricata L.) irrigated with saline water and under exogenous application of hydrogen peroxide (H2O2) in the post-grafting phase. A study was conducted in Campina Grande, PB, under greenhouse conditions. The treatments were distributed in a randomized block design, in a 4 × 2 factorial arrangement, consisting of four levels of electrical conductivity of water (ECw; 1.6; 2.4; 3.2 and 4.0 dS m-1) and two concentrations of H2O2 (0 and 20 µM) with four replications. Irrigation water salinity from 1.6 dS m-1 caused changes in the stomatal conductance, respiration, and internal CO2 concentration of soursop plants. A 20 µM concentration of H2O2 reduced the effects of salinity on transpiration and CO2 assimilation values, in addition to promoting the biosynthesis of photosynthetic pigments and reducing cell damage in soursop plants, at 150 days after transplantation. The exogenous application of 20 µM H2O2 reduced the deleterious effects of salinity on the stem diameter of both rootstock and scion in soursop plants irrigated with ECw of 1.6 dS m-1. The exogenous application of 20 µM H2O2 was not efficient in mitigating the damage caused by salinity on the stem diameter of the soursop at grafting point.

Crescimento inicial do girassol cultivar SYN045 sob irrigação com estresse salino

Tem-se como objetivo analisar o comportamento do crescimento inicial do girassol, cultivar SYN045, influenciado por diferentes níveis de salinidade na água de irrigação. O trabalho foi implantado e conduzido na Unidade Educativa de Campo do Grupo de Estudos e Pesquisa Agropecuária na Caatinga – GEPAC no Instituto Federal Baiano, Campus Serrinha, situado no município de Serrinha no Estado da Bahia. A pesquisa foi constituída de quatro níveis de água salina com cinco repetições cada, com uma planta por vaso, totalizando 20 plantas. Os tratamentos utilizados com água salina foram: S0= 0,4; S1= 2,2; S2= 4,4 e S3= 6,6 dS.m-1. Para diferenciar os tratamentos salinos, foram adicionados o NaCl, CaCl2.2H2O e MgCl2.6H2O, na proporção de 7:2:1 à água de abastecimento. Foram analisadas as variáveis de altura caulinar da planta e Taxa de Crescimento Absoluto Caulinar. Com os resultados obtidos em campo é possível afirmar que o aumento das concentrações de sais na água de irrigação afeta de forma negativa o crescimento e desenvolvimento da cultura do girassol cultivar SYN045.

Arbuscular mycorrhizal fungi as mitigating agents of salt stress in Formosa papaya seedlings

The objective of the present study was to evaluate the effect of mycorrhization on the nutritional, hydric and biochemical components of papaya seedlings, Carica papaia L., from the Formosa Group, Hybrid Tainung Nº 1, submitted to irrigation with saline water. The research was conducted at the Federal Institute of Paraíba, Sousa Campus, from March to December 2018. The experimental design used completely randomized blocks, with treatments arranged in a 4 x 5 factorial scheme, referring to the fungi species: Gigaspora candida, Acaulospora scrobiculata, Dentiscutata heterogama and without mycorrhizae, and the five salt concentrations in irrigation water: 0.0; 10.0; 20.0; 30.0 and 40.0 mmolc L-1 in four repetitions. The characteristics evaluated were: relative water content, water saturation deficit, membrane damage, photosynthetic pigments, concentration and accumulation of nitrogen, phosphorus, potassium, sodium and the relationship between potassium and sodium concentrations in leaf tissue. The species D. heterogama and G. candida presented the highest rates of leaf hydration and the lowest damage to biomembranes at all saline levels. Mycorrhizae increased the absorption of N and P, especially from 30 mmolc L-1 of salt. A greater relationship between potassium and sodium concentrations was evidenced in seedlings mycorrhized with D. heterogama.

Changes in Agronomic and Physiological Traits of Sugarcane Grown with Saline Irrigation Water

In Japan, the highest salt concentration in irrigation water for sugarcane cultivation has been reported to be above 2500 mg L−1, which may cause harmful effects to the crops; however, little information is available on the relationship between the salinity of irrigation water and sugarcane. To investigate its effects on agronomic and physiological traits, a Japanese cultivar, Saccharum spp cv. NiF8, was grown with 0, 200, 500, 1000, 2000, and 3000 mg NaCl L−1 under pot conditions. The treatments significantly lowered leaf area; however, NaCl levels up to 500 mg L−1 did not greatly reduce culm weight and juice sugar concentration. These traits were impaired when the tested cultivar was grown with 1000 mg NaCl L−1 or higher, indicating that salt concentration is desired to be lower than 1000 mg L−1. CO2 assimilation rate was inhibited mainly due to stomatal closure caused by salt stress. The treatments significantly altered Na+, Cl−, and K+ concentrations in juice but not those in leaf, suggesting that juice analysis is an effective method to estimate its salinization status. Culm weight and juice sugar concentration were severely affected as juice conductivity exceeded 900 mS m−1; thereby, sugarcane plants of NiF8 possessing conductivity above this level could be considered salt-stressed where water salinity is a concern.

Yield of maize crop irrigated with saline waters

ABSTRACT The growing competition for good-quality water is forcing the use of saline water for irrigation in several areas around the world. The objective of this study was to evaluate the influence of different electrical conductivities of irrigation water on the maize production aspects. The study was conducted in the field from August to December 2017 at the Experimental Farm of the Universidade da Integração Internacional da Lusofonia Afro-Brasileira (UNILAB), Redenção, CE, Brazil. A randomized complete block design with five irrigation water salinity (1.0, 2.0, 3.0, 4.0 and 5.0 dS m-1) and four repetitions was used. The evaluated variables were: unhusked and husked ear weights, husked ear length and diameter, cob weight, 1000-grain weight and yield. The increase of salt concentration in irrigation water reduced the unhusked and husked ear weights, cob weight, 1000-grain weight and yield. Ear length and diameter were not influenced by the increase in water salinity.

Physiological responses of lima bean subjected to salt and water stresses

ABSTRACT Under water deficit and/or salt stress conditions, crops suffer from several physiological disturbances, which lead to the reduction in growth and, consequently, decreases in their yields. Thus, the objective of this study was to evaluate the physiological responses of lima bean, cultivar Espírito Santo, under different irrigation water salinity associated to two water regimes. The experiment was carried out in the experimental area of the Universidade Federal do Ceará, Brazil, from September to November 2017, and it was carried out in pots in full sun, under a completely randomized design in split plots, where water salinities (1.1, 2.1, 3.1, 4.1 and 5.1 dS m-1) were considered as the plots, and the treatments of water regime (50 and 100% of the reference evapotranspiration - ETo) were considered as the subplots. At 45 days after sowing, leaf gas exchanges and relative index of total chlorophyll (SPAD index) were evaluated. In general, the increase of salt concentration in irrigation water causes reductions in the physiological responses of lima beans. Under a water regime of 50% ETo, the instantaneous and intrinsic water use efficiency is higher.

Hydrogen peroxide on acclimation of soursop seedlings under irrigation water salinity

The Brazilian Northeast region provides favorable conditions for the exploitation of several crops, but the high salt concentration in irrigation water constitutes a limiting factor for production in most cases. In this context, this study aimed to evaluate the emergence, growth and partition of photoassimilates in soursop seedlings, cv. ‘Morada Nova’, subjected to irrigation with water of increasing salinity levels and to exogenous application of hydrogen peroxide. The study was carried out in plastic bags under greenhouse conditions, using a sandy loam Regolithic Neosol, in the municipality of Campina Grande, PB, Brazil. Treatments were distributed in randomized blocks, in a 5 x 5 factorial arrangement, relative to five levels of irrigation water electrical conductivity - ECw (0.7, 1.4, 2.1, 2.8 and 3.5 dS m-1) and five concentrations of hydrogen peroxide - H2O2 (0, 25, 50, 75 and 100 µM), with four replicates and three plants per plot. Increasing salt concentration compromised all variables analyzed and leaf area was most sensitive. As irrigation water electrical conductivity increased, the deleterious effects of water salinity on the emergence percentage, emergence speed index, stem diameter and leaf area were attenuated by the exogenous application of hydrogen peroxide, with highest efficiency at the concentration of 50 µM. Hydrogen peroxide concentrations above 38 µM inhibited the specific leaf area of soursop, cv. ‘Morada Nova’.

Screening for Salt Tolerance in Four Local Varieties of Phaseolus lunatus from Spain

This study assessed the responses of four local Spanish cultivars of Phaseolus lunatus (lima bean) to moderate salinity. For three weeks, plants were exposed to increasing salinity (50–150 mM NaCl) under greenhouse conditions. At the end of the experiment, several growth and biochemical parameters were determined. Salt stress reduced the fresh weight of aerial organs, allowing us to rank the four genotypes according to their tolerance to salinity. The concentration of most photosynthetic pigments remained unaltered, except carotenoids that were reduced in the least salt-tolerant cv. (cultivar) VPH-79. Leaf Na+ and Cl− concentrations increased with increased salt concentration of irrigation water, but K+ either remained constant, as in the most tolerant ‘BGV-15410’, or increased in the other cultivars, resulting in an unchanged K+/Na+ ratio under stress in two of the selected cultivars. Moreover, proline increased in all cultivars, most notably in cv. VPH-79, with the highest absolute concentrations registered in the more salt tolerant cultivars. Interestingly, these cultivars already had a relatively higher proline concentration in non-stressed plants. These findings indicate that P. lunatus is moderately salt tolerant and that its main mechanisms to adjust to salinity stress are the maintenance of high concentrations of K+ and proline accumulation in leaves.

Salinity impacts on experimental fodder sorghum production

Field experiment was conducted at research station of Soil, Water & Environment Discipline, Khulna University, during the dry season to see the growth performance of sorghum (Sorghum bicolor L. cv. Morokoshi) irrigating with saline water. For irrigation, river water (RW) containing EC value of 14.04 dS m-1 was collected from the Rupsha river, Khulna and mixed with tap water [TW] containing EC value of 0.78 dS m-1at three different ratios (3:1, 1:1 and 1:3 v/v). After mixing, water containing five different EC values (0.78, 4.19, 7.18, 10.79 and 14.04 dS m-1) were obtained and considered as salinity treatment. Harvesting and sampling was done 83 days after transplanting (DAT) by cutting four sorghum plants randomly selected from each plot. Different morphological parameters such as plant height, leaf number, leaf length, leaf width, stem diameter and plant biomass were measured and recorded. Soil samples were also collected from each plot. Under water salinity stress, all the agronomic attributes and plant biomass showed a decreasing tendency with increasing salt concentration in irrigation water but the growth was not harmfully affected at lower levels of salinity. Plant height and biomass was significantly decreased irrigating with water containing salinity 10.79 dS m-1.After harvest it was found that irrigation with saline water up to 10.79 dS m-1 did not show any increase of soil salinity. It was probably due to rainfall during the monsoon which was occurred at the later stage of the growing period. So, the fodder sorghum plant might be cultivated in the coastal regions of Bangladesh where fresh water irrigation is limited due to salinity problem as well as might be grown irrigating with saline water up to 10.79 dS m-1.SAARC J. Agri., 16(1): 145-155 (2018)

Response of Jatropha integerrima Plants Irrigated with Different Levels of Saline Water to Nano Silicon and Gypsum

An open field experiment was carried out during 2015 and 2016 seasons at the experimental nursery of the Ornamental Horticulture Department, Faculty of Agriculture, Cairo University, Egypt. The purpose of present research was to investigate the effect of foliar application of nano silicon with different concentrations and gypsum soil application on growth, flowering and chemical constituents of Jatropha integerrima plants irrigated with different levels of saline water. The concentrations of saline water were (1000, 2000 and 4000 ppm), in addition to tap water (270 ppm) as a control, simultaneously plants were received monthly foliar application of nano silicon 1 and 2 mM or soil application of gypsum at 20 g/plant, either applied individually or in combination.The results showed that, elevating salt concentration in irrigation water decreased vegetative growth characteristics, flowering traits, leaves anatomy and chemical constituents. In contrast, increasing salinity of irrigation water boosted contents of proline, Ca%, Na%, Cl%, total phenolic and flavonoids. On the other hand, foliar application of nano silicon and soil addition of gypsum treatments either individually or in combination had favorable effects on enhancing vegetative parameters and chemical constitutes, meanwhile decreasing accumulation of Na%, Cl%, total phenolic and flavonoids in leaves. It can be concluded that, foliar spray of nano silicon combined with soil addition of gypsum was the best effective and economic treatment recommended for mitigating the harmful effect of salinity stress on Jatropha plants irrigated with saline water at concentration up to 4000 ppm.

Influence of exogenous application of some phytoprotectants on growth, yield and pod quality of snap bean under NaCl salinity

Snap bean is a salt sensitive plant and suffers from losses in yield and pod quality with any little increase of salt concentration in irrigation water. In order to study the effect of salicylic acid (SA), spermidine (Spd), and glycine betaine (GB) as phytoprotectants on enhancing growth, yield and pod quality of snap bean under different levels of NaCl salinity, an outdoor pot experiment was conducted in 2012 and 2013 seasons. Salinity was applied as NaCl form at 0 and 2000ppm. The concentrations of foliar treatments were two levels for each treatment; the first level was 0mM which served as control, and the second level was 1mM SA, 0.5mM Spd and 5mMGB, in addition to their combinations. NaCl salinity at 2000ppm reduced most of vegetative growth parameters such as plant f.w., leaf area ratio and leaf area index, which in turn reflected on the reduction of pods no./plant and yield f.w./plant and an increase in the fruit abscission percentage. Pod moisture % decreased under 2000ppm NaCl which reduced pod f.w., and increased pod curvature %. Under 2000ppm NaCl, GB at 5mM and all its combinations increased membrane stability index, total soluble sugars and total soluble proteins concentration, while reducing free amino acids concentration, which were concomitant with decreasing pod curvature %. Meanwhile, application of SA at 1mM, GB at 5mM, and GB5+SA1+Spd0.5 increased leaves and pods no./plant, pod moisture %, and pod f.w., which reflected on increasing green pod yield.

Impact of saline water irrigation on water use efficiency and soil salt accumulation for spring maize in arid regions of China

Saline water irrigation represents the future of agriculture in the arid regions of northwestern China. Therefore, saline water irrigation experiments for spring maize were performed for 3 years from 2009 to 2011 in arid regions of northwestern China, and the impact of irrigation with saline water at different concentrations on the water use efficiency and soil salt accumulation was investigated. A SWAP model was calibrated and verified using field experiment data. The relationships of the salt concentration of the irrigation water with the yield and water use efficiency of spring maize were simulated using the SWAP model. Furthermore, the salt transport across the soil layers was quantitatively analyzed. The results showed the following: (1) irrigation with water containing low concentrations of saline (<3g/L) for 3 consecutive years combined with a single application of fresh spring water before sowing every year did not cause significant changes in the yield of spring maize. (2) Saline water irrigation for 3 consecutive years resulted in an increase in the salt accumulation at a soil depth of 0–100cm in 2011. This finding indicated that spring irrigation did not completely leach the salt introduced by saline water irrigation. (3) The SWAP simulation indicated that the yield of spring maize declined by 622kg/ha for every 1g/L increase in the salt concentration. When the salt concentration of the irrigation water was less than 3g/L, the yield of the spring maize was reduced by less than 10%, whereas salt concentrations above 3g/L decreased the yield much more significantly. A simulation over 10 consecutive years of saline water irrigation showed that the spring maize yields of T3, T6 and T9 will reduce by 8%, 33% and 52%, respectively, compared with the yield in 2009. (4) Despite the differences in the salt concentration of irrigation water, the salt residue in the 0–100cm soil layer due to irrigation with 3g/L, 6g/L and 9g/L saline water accounted for approximately 60% of the total salt in the irrigation water in 2011. The remaining 40% of the salt leached to the soil layer below 100cm. In conclusion, irrigation with saline water at concentrations below 3g/L will reduce the yield by no more than 10% compared with fresh water irrigation, but long-term saline water irrigation will result in significant yield losses, even for low concentrations of salt. Thus, the accumulation of salt in the soil after many years of saline water irrigation needs to be addressed by using a proper irrigation schedule in order to ensure the sustainability of saline water irrigation.

Zinc and cadmium availability as affected by zinc fertilization and saline water irrigation in wheat (Triticum aestivum L.) grown on cadmium polluted soil

Two-year’s study was carried out to evaluate the effect of zinc fertilization and salinity created by NaCl and NaNO3 on the fate of zinc (Zn) and cadmium (Cd) in soil and their contents in wheat grain grown in a cadmium polluted soil. Increasing NaCl rates increased total cadmium (Cd), Cd2+, CdCl+, CdHCO3+, and CdCl2O concentrations in soil solution, whereas no such effects were found for the NaNO3 treatments. Higher salt content of saline irrigation water decreased total zinc (Zn) and free Zn2+ concentrations in soil solution and also reduced Zn concentration in the wheat grain. Zinc fertilization enhanced grain Zn contents but reduced that of Cd. Increasing salt concentration in irrigation water decreased plant dry matter and grain number per ear head especially, when no zinc was applied. Application of zinc had positive effects on the salt tolerance of plant and increased dry matter yield and grain number per ear head. Chloride mobilizes soil Cd and increased its bio-availability; therefore, higher Cd in wheat grain is mainly attributed to increased soil Cl concentration with the use of NaCl irrigation water. The results indicated that Zn application reduces Cd concentration in grain produced on Cd polluted soils. Key words: Salinity, zinc fertilization, wheat, cadmium (Cd) polluted soils.

Efeito da salinidade na emergência e crescimento inicial de plântulas de flamboyant

Objetivou-se avaliar o efeito de diferentes concentrações salinas na água de irrigação na emergência e desenvolvimento inicial de plântulas de flamboyant (Delonix regia (Bojer ex Hook.) Raf.). O experimento foi desenvolvido em casa de vegetação do Departamento de Ciências Vegetais da Universidade Federal Rural do Semiárido - UFERSA, Mossoró-RN. O delineamento estatístico utilizado foi o inteiramente casualizado, com cinco tratamentos e quatro repetições, com 25 sementes cada. Os tratamentos consistiram das concentrações salinas (0,5; 1,5; 3,0; 4,5 e 6,0 dS m-1), que foram obtidas através da adição de NaCl em água de forma que as soluções fossem calibradas para as condutividades elétricas pré-estabelecidas. As variáveis avaliadas foram: porcentagem de emergência de plântulas, índice de velocidade de emergência, área foliar, altura de plântula, número de folíolos, comprimento de raiz e massa seca da parte aérea. A salinidade interfere negativamente em todas as variáveis avaliadas de forma proporcional ao seu aumento na água de irrigação das plântulas de flamboyant, sendo o maior desenvolvimento das plântulas obtido na dose 0,5 dS m-1.

Combined Effects of Water Quality and Furrow Gradient on Runoff and Soil Erosion in North China

Irrigation-induced soil erosion seriously affects the sustainability of irrigated agriculture. The effects of irrigation water quality and furrow gradient on runoff and soil loss were studied under simulated furrow irrigation in laboratory using a soil collected from an experimental station of China Agricultural University, North China. The experimental treatments were different combinations of irrigation water salt concentrations of 5, 10, 20, and 30 mmol c L −1, sodium adsorption ratios (SAR) of 0.5, 5.0, and 10.0 (mmol c L −1) 0.5, and furrow gradients of 1%, 3%, and 5%, with distilled water for irrigation at 3 furrow gradients as controls. The experimental data indicated that total runoff amount, sediment concentration in runoff, and total soil loss amount generally decreased with increasing salt concentration in irrigation water but increased with its sodicity and furrow gradient. The effects of water quality and furrow gradient on soil loss were greater than those on runoff, and the increase of furrow gradient decreased the influence of water quality on soil loss. When the salt concentration increased from 5 to 30 mmol c L −1 at SAR of 10.0 (mmol c L −1) 0.5, total runoff amount, sediment concentration, and total soil loss amount decreased by 3.89%, 52.1%, and 53.92%, and 10.57%, 38.86%, and 42.03% at the furrow gradients of 1% and 5%, respectively. However, they respectively increased by 3.37%, 45.34%, and 55.36%, and 3.86%, 10.77%, and 13.91% when SAR increased from 0.5 to 10.0 (mmol c L −1) 0.5 at the salt concentration of 5 mmol c L −1. Irrigation water quality and furrow gradient should be comprehensively considered in the planning and management of furrow irrigation practices to decrease soil loss and improve water utilization efficiency.