scholarly journals Morphophysiological Traits of Gray Mangrove (Avicennia marina (Forsk.) Vierh.) at Different Levels of Soil Salinity

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Kholoud Abou Seedo ◽  
Mohammad S. Abido ◽  
Ahmed Salih ◽  
Asma Abahussain

The traits of gray mangrove (Avicennia marina (Forsk.) Vierh.) at different levels of soil salinity were assessed at three sites along the Tubli Bay coastline of Bahrain. Morphophysiological traits include rates of photosynthesis and transpiration, leaf morphology, and leaf pigment content. Results showed that the rates of photosynthesis and transpiration, the intercellular CO2 concentration, and stomatal conductance were significantly lower (p ≤ 0.05) in the trees of a low salinity site compared to those of high salinity sites. Pairwise correlation between soil electrical conductivity levels and photosynthesis and transpiration rates was very low, implying an adverse effect of low salinity on both processes. However, the dimensions of leaf area and the sclerophylly index were significantly higher (p ≤ 0.05) in the trees grown in low salinity site compared to those in more saline conditions. On the other hand, pigments were significantly lower in leaves of trees grown in low salinity site compared to the other two sites. The pairwise correlation between electrical conductivity values and chlorophyll a, b, and carotenoid was 0.51, 0.52, and 0.57 consecutively at (p <0.0001), implying moderate effect of salinity on leaf pigments. This study illustrates the adverse and positive effects of soil salinity on some traits of gray mangrove in Bahrain, which might be considered in ecosystem rehabilitation along other coastlines of the country.

2021 ◽  
Vol 13 (10) ◽  
pp. 1875
Author(s):  
Wenping Xie ◽  
Jingsong Yang ◽  
Rongjiang Yao ◽  
Xiangping Wang

Soil salt-water dynamics in the Yangtze River Estuary (YRE) is complex and soil salinity is an obstacle to regional agricultural production and the ecological environment in the YRE. Runoff into the sea is reduced during the impoundment period as the result of the water-storing process of the Three Gorges Reservoir (TGR) in the upper reaches of the Yangtze River, which causes serious seawater intrusion. Soil salinity is a problem due to shallow and saline groundwater under serious seawater intrusion in the YRE. In this research, we focused on the temporal variation and spatial distribution characteristics of soil salinity in the YRE using geostatistics combined with proximally sensed information obtained by an electromagnetic induction (EM) survey method in typical years under the impoundment of the TGR. The EM survey with proximal sensing method was applied to perform soil salinity survey in field in the Yangtze River Estuary, allowing quick determination and quantitative assessment of spatial and temporal variation of soil salinity from 2006 to 2017. We developed regional soil salinity survey and mapping by coupling limited laboratory data with proximal sensed data obtained from EM. We interpreted the soil electrical conductivity by constructing a linear model between the apparent electrical conductivity data measured by an EM 38 device and the soil electrical conductivity (EC) of soil samples measured in laboratory. Then, soil electrical conductivity was converted to soil salt content (soil salinity g kg−1) through established linear regression model based on the laboratory data of soil salinity and soil EC. Semivariograms of regional soil salinity in the survey years were fitted and ordinary kriging interpolation was applied in interpolation and mapping of regional soil salinity. The cross-validation results showed that the prediction results were acceptable. The soil salinity distribution under different survey years was presented and the area of salt affected soil was calculated using geostatistics method. The results of spatial distribution of soil salinity showed that soil salinity near the riverbanks and coastlines was higher than that of inland. The spatial distribution of groundwater depth and salinity revealed that shallow groundwater and high groundwater salinity influenced the spatial distribution characteristics of soil salinity. Under long-term impoundment of the Three Gorges Reservoir, the variation of soil salinity in different hydrological years was analyzed. Results showed that the area affected by soil salinity gradually increased in different hydrological year types under the impoundment of the TGR.


Soil Research ◽  
1997 ◽  
Vol 35 (3) ◽  
pp. 515 ◽  
Author(s):  
I. Vogeler ◽  
B. E. Clothier ◽  
S. R. Green

In order to examine whether the electrolyte concentration in the soil solution can be estimated by time domain reflectometry (TDR) measured bulk soil electrical conductivity, column leaching experiments were performed using undisturbed soil columns during unsaturated steady-state water flow. The leaching experiments were carried out on 2 soils with contrasting pedological structure. One was the strongly structured Ramiha silt loam, and the other the weakly structured Manawatu fine sandy loam. Transport parameters obtained from the effluent data were used to predict the transient pattern in the resident electrolyte concentration measured by TDR. The electrolyte concentration was inferred from the TDR-measured bulk soil electrical conductivity using 2 different calibration approaches: one resulting from continuous solute application, and the other by direct calibration. Prior to these, calibration on repacked soil columns related TDR measurements to both the volumetric water content and the electrolyte concentration that is resident in the soil solution. The former calibration technique could be used successfully to describe solute transport in both soils, but without predicting the absolute levels of solute. The direct calibration method only provided good estimates of the resident concentration, or electrolyte concentration, in the strongly structured top layer of the Ramiha soil. This soil possessed no immobile water. For the less-structured layer of the Ramiha, and the weakly structured Manawatu soil, only crude approximations of the solute concentration in the soil were found, with measurement errors of up to 50%. The small-scale pattern of electrolyte movement of these weakly structured soils appears to be quite complex.


1986 ◽  
Vol 66 (2) ◽  
pp. 315-321 ◽  
Author(s):  
N. C. WOLLENHAUPT ◽  
J. L. RICHARDSON ◽  
J. E. FOSS ◽  
E. C. DOLL

This study presents a method for calibrating electromagnetic induction instrument readings with saturated paste electrical conductivity (ECe) for field mapping purposes. Each meter reading represents an integration of the apparent soil electrical conductivity (ECa) over the meter’s response depth. To correlate the meter readings with measured ECe within soil depth increments, several pedons representing a range of soil salinity for the survey area were sampled in 30-cm increments to a depth corresponding to the meter response. A weighting procedure based on the meter response-depth function was developed to condense the multiple ECe by depth measurements into a single weighted area specific value. These values were correlated with the apparent soil electric conductivity from the electromagnetic induction instrument by simple linear regression. This technique is designed for soil association of similar parent materials. The resulting regression equation yields a quick reliable equation that avoids complex mathematics and converts the instrument readings into weighted forms of commonly used saturated paste electrical conductivity values. Key words: Soil survey, electrical resistance


2016 ◽  
Vol 4 (1) ◽  
Author(s):  
Erly Kaligis

Absolute Growth, hemolymp  osmolality, oxygen consumption, and basal energy of  Litopenaeus vannamei postlarvae were investigated. After post larval stage, PL-20, the postlarvae were acclimatized from sea water (25 ppt) to low salinity  water (2 ppt) over 96 h. Treatments consisted of different concentration of K+added to distilled water. Four different levels of K+ (0, 30, 60, and 90 ppm) were utilized. Ten shrimp were placed in triplicate 40-L glasses aquarium.  Results from the 42-day K+ growth trial indicated significant differences (P< 0.05) in absolute growth, hemolymp osmolality,  oxygen comsumption, and  basal energy. The values in treatment A was significantly higher than than those under the other four treatments. The results suggest treatment C were the optimum K+ level for culture  vaname postlarvae in low salinity water. Keywords :  Litopenaeus vannamei, oxygen comsumption, hemolymp


Irriga ◽  
2009 ◽  
Vol 14 (3) ◽  
pp. 383-397 ◽  
Author(s):  
Sergio Oliveira Pinto de Queiroz ◽  
Roberto Testezlaf ◽  
Edson Eiji Matsura

METODOLOGIA PARA AVALIAÇÃO DA SALINIDADE DO SOLO EM AMBIENTE PROTEGIDO  Sérgio Oliveira Pinto de Queiroz1; Roberto Testezlaf2; Edson Eiji Matsura21Departamento de Tecnologia e Ciências Sociais, Universidade do Estado da Bahia, Juazeiro, BA,  [email protected]. 2Faculdade de Engenharia Agrícola, Universidade Estadual de Campinas, Campinas, SP  1 RESUMO Em condições de ambiente protegido a irrigação é essencial e a fertirrigação um agente facilitador do manejo da água e fertilização do solo; todavia, o uso contínuo e nem sempre adequado pode elevar a salinidade do solo, comprometendo o processo produtivo. Este trabalho objetivou avaliar uma metodologia para caracterizar a ocorrência de salinização em cultivos protegidos, usando diferentes métodos para determinação da condutividade elétrica do solo. Em laboratório foram avaliados os equipamentos Sensor Sigma Probe EC1, da Delta-T e extratores de solução do solo à vácuo. Os equipamentos foram utilizados em três solos com diferentes texturas e sob cinco níveis de salinidade: 0, 2, 4, 8 e 12 dS. m-1 a 25° C. Os resultados obtidos pelos métodos avaliados foram comparados ao método do extrato de saturação. O equipamento Sigma Probe EC1, por apresentar melhor correlação com o método de referência na fase laboratorial, foi utilizado nas visitas as propriedades, sob produção em ambiente protegido, na macrorregião de Campinas, revelou ser mais eficiente. A aplicação do questionário associada às leituras de condutividade elétrica do solo com o sensor Sigma Probe permitiu diagnosticar a deficiência no manejo da água e condutividade elétrica nas propriedades avaliadas. Os valores obtidos de condutividade elétrica no extrato de saturação do solo para as propriedades visitadas, não caracterizam solos salinos, mas podem afetar a produção de flores e outras plantas sensíveis à salinidade. UNITERMOS: manejo da irrigação; fertirrigação.  QUEIROZ, S. O. P. de.; TESTEZLAF, R.; MATSURA, E. E. METHODOLOGY FOR SOIL SALINITY EVALUATION IN GREENHOUSE  2 ABSTRACT Under controlled environmental conditions, irrigation is essential and the use of fertigation becomes a facilitator agent for water and fertilization management. However, the intensive use of fertigation in this type of productive process can increase soil salinity, and affect productive process. This work objective was to evaluate a methodology in order to characterize the salinization process occurrence of in greenhouse farms using different methods to determine soil electric conductivity l. Sigma Probe EC1, manufactured by Delta-T and vacuum solution manufactured extractors were evaluated under laboratory conditions. The equipment was used in three different soil textures, under five salinity levels: 0, 2, 4, 8 and 12 dS. m-1 at 25° C. The obtained results of electric conductivity were compared to the saturation extract method. The Sigma Probe EC1 equipment was used in farm visits, with controlled environmental production inCampinas macro region. Among the used equipment in the laboratorial part, the sigma Probe EC1 presented the best results for soil electrical conductivity determination, when compared to saturation extract, in saline and non saline soils. Using the questionnaire for electric conductivity determinations using Sigma Probe sensor it was possible to verify the deficiency in the soil moisture and electrical conductivity management. The obtained results for electric conductivity using the saturation extract methods do not characterize saline soils on the visited farms, but they showed that the salinity levels in the soil could affect flower production and other crops sensitive to salinity. KEYWORDS: irrigation management, fertigation.


Atmosphere ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 73
Author(s):  
Lorenzo De Carlo ◽  
Gaetano Alessandro Vivaldi ◽  
Maria Clementina Caputo

This paper focused on the use of electromagnetic induction measurements in order to investigate soil salinization caused by irrigation with saline reclaimed water. An experimental activity was carried out during the growing season of tomato crop in order to evaluate expected soil salinization effects caused by different saline agro-industrial wastewaters used as irrigation sources. Soil electrical conductivity, strictly related to the soil salinity, has been monitored for three months by means of Electromagnetic Induction (EMI) measurements, and evident differences in the soil response have been observed. The study highlighted two aspects that can improve soil investigation due to the utilization of geophysical tools. First, EMI data can map large areas in a short period of time with an unprecedented level of detail by overcoming practical difficulties in order to massively sample soil. At the same time, repeated measurements over time allow updating real-time soil salinity maps by using accurate correlations with soil electrical conductivity. This application points out how integrated agro-geophysical research approaches can play a strategic role in agricultural saline water management in order to prevent soil salinization risks in medium to long-term periods.


1990 ◽  
Vol 54 (1) ◽  
pp. 46-54 ◽  
Author(s):  
J. D. Rhoades ◽  
P. J. Shouse ◽  
W. J. Alves ◽  
Nahid A. Manteghi ◽  
S. M. Lesch

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