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Abstract The effect of pyrolysis temperature (T) and biomass particle size (z) on the biocoal's heating value of Oak acorn shell (OA), deseeded carob pods (CP) and olive mill solid waste (OMSW) were investigated. The higher heating... more
Abstract The effect of pyrolysis temperature (T) and biomass particle size (z) on the biocoal's heating value of Oak acorn shell (OA), deseeded carob pods (CP) and olive mill solid waste (OMSW) were investigated. The higher heating value (HHV) increased with T. The effect of the particle size differed according to the biomass. Response surface methodology (RSM) was used to optimise the biocoal production system from technical, end-user and socio-environmental perspectives. The maximum HHV, representing the technical objective, is achieved at maximum T and minimum z for OA biocoal; at maximum T and minimum z for OMSW and at maximum T and maximum z for CP. The highest lower heating value (LHV), corresponding to end-user, for OA biocoal is achieved when T is greater than 450 °C and z 1750 μm. The maximum net energy return per kg of biomass processed and maximum GHG offset (socio-economic) is realised at the lowest T for all biomass and particle sizes. This study is relevant to policy makers as it highlights potential conflict between the optimal conditions to produce high quality biocoal characterised by its high LHV and the optimal conditions to achieve the maximum utility from the resource and in turn potentially higher socio-environmental return.
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An alternative strategy for saving limited water resources is using treated wastewater (TWW) originating from wastewater treatment plants. However, using TWW can influence soil properties owing to its characteristics compared to... more
An alternative strategy for saving limited water resources is using treated wastewater (TWW) originating from wastewater treatment plants. However, using TWW can influence soil properties owing to its characteristics compared to conventional water resources. Therefore, assessing the effect of TWW on soil properties and soil water infiltration is crucial to maintain sustainable use of TWW and to increase the water use efficiency of the precious irrigation water. Moreover, several studies were carried out to assess the performance of infiltration models. However, few studies evaluate infiltration models under the use of treated wastewater. Therefore, this study aims to assess the effect of TWW irrigation on soil properties after 2 and 5 years and to evaluate five classical infiltration models with field data collected from soil irrigated by treated wastewater for their capability in predicting soil water infiltration. This study revealed that using TWW for irrigation affects significantly on soil properties after 2 and 5 years. The soil irrigated with TWW had significantly higher electrical conductivity, organic matter, sodium adsorption ratio, cation exchange capacity, and lower soil bulk density compared to control. The basic infiltration rate and cumulative infiltration decreased significantly compared to control (60.84, 14.04, and 8.42 mm hr−1 and 140 mm, 72 mm, and 62 mm for control, 2, and 5 years’ treatments, respectively). The performance of the infiltration models proposed by Philip, Horton, Kostiakov, Modified Kostiakov, and the Natural Resources Conservation Service was evaluated with consideration of mean error, root mean square error, model efficiency, and Willmott’s index. Horton model had the lowest mean error (0.0008) and Philip model had the lowest root mean square error (0.1700) while Natural Resources Conservation Service had the highest values (0.0433 and 0.5898) for both mean error and root mean square error, respectively. Moreover, Philip model had the highest values of model efficiency and Willmott’s index, 0.9994 and 0.9998, respectively, whereas Horton model had the lowest values for the same indices, 0.9869 and 0.9967, respectively. Philip model followed by Modified Kostiakov model were the most efficient models in predicting cumulative infiltration, while Natural Resources Conservation Service model was the least predictable model.
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BackgroundTomatoes (Solanum lycopersiconL.) are one of the main daily consumed vegetables in the human diet. Tomato has been classified as moderately sensitive to salinity at most stages of plant development, including seed germination,... more
BackgroundTomatoes (Solanum lycopersiconL.) are one of the main daily consumed vegetables in the human diet. Tomato has been classified as moderately sensitive to salinity at most stages of plant development, including seed germination, seedling (vegetative), and reproduction phases. In this study, we evaluated the performance and response of 39 tomato landraces from Jordan under salt stress conditions. Furthermore, the landraces were also genetically characterized using simple sequence repeat (SSR) markers.ResultsThe studied morphological-related traits at the seedling stage were highly varied among landraces of which the landrace number 24 (Jo970) showed the best performance with the highest salt tolerance. The total number of amplification products produced by five primers (LEaat002, LEaat006, LEaat008, LEga003, LEta019) was 346 alleles. Primer LEta 019 produced the highest number of alleles (134) and generated the highest degree of polymorphism (100%) among landraces in addition...
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Soil water infiltration is a critical process in the soil water cycle and agricultural practices, especially when wastewater is used for irrigation. Although research has been conducted to evaluate the changes in the physical and chemical... more
Soil water infiltration is a critical process in the soil water cycle and agricultural practices, especially when wastewater is used for irrigation. Although research has been conducted to evaluate the changes in the physical and chemical characteristics of soils irrigated by treated wastewater, a quantitative analysis of the effects produced on the infiltration process is still lacking. The objective of this study is to address this issue. Field experiments previously conducted on three adjacent field plots characterized by the same clayey soil but subjected to three different irrigation treatments have been used. The three irrigation conditions were: non-irrigated (natural conditions) plot, irrigated plot with treated wastewater for two years, and irrigated plot with treated wastewater for five years. Infiltration measurements performed by the Hood infiltrometer have been used to estimate soil hydraulic properties useful to calibrate a simplified infiltration model widely used und...
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The aim of this study was to assess the potential use of biochar derived from olive pruning to enhance soil properties and tomato and bell pepper plant growth and yield performance in arid environments. Biochar was prepared from olive... more
The aim of this study was to assess the potential use of biochar derived from olive pruning to enhance soil properties and tomato and bell pepper plant growth and yield performance in arid environments. Biochar was prepared from olive tree–pruning residues. The biochar was applied to field experiments of tomato and bell pepper plants at five application rates (0, 8, 16, 30, and 40 t ha−1). Relative water content (RWC), leaf chlorophyll, and leaf nutrient (nitrogen (N), phosphorus (P), and potassium (K)) contents were measured. The total yield was determined for each treatment. Fruit nutrient contents were determined in selected fruit samples. Soil samples were collected from each treatment at the middle and end of the experiment for physical and chemical analysis. All experiments were conducted in triplicate. The application of biochar at rates of 8 and 16 t ha−1 enhanced tomato and bell pepper growth; however, application of 30 and 40 t ha−1 adversely affected tomato and bell pepper growth. Nutrient analysis showed that N, P, and K concentrations in leaves and fruits were higher in plants treated with 8 and 16 t ha−1 of biochar than in biochar treatments of 30 and 40 t ha−1. Higher biochar application rates increased soil pH and EC by 1.4% and 12.3% (8 t ha−1) to 7.3% and 107.8% (40 t ha−1), respectively. A biochar application rate of 8 t ha−1 is recommended as an optimal rate to enhance soil fertility for tomato and bell pepper production systems in arid environments.
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Soil salinity is best estimated by saturated paste extract (ECe), the most reliable monitoring method to assess plant growth that is directly related to the field water content. However, this procedure is laborious and time-consuming,... more
Soil salinity is best estimated by saturated paste extract (ECe), the most reliable monitoring method to assess plant growth that is directly related to the field water content. However, this procedure is laborious and time-consuming, therefore, more convenient methods such as 1:5 soil: water extract is commonly used to estimate the ECe. Traditionally, a conversion factor (CF) based on a linear correlation between the diluted extract and ECe is employed for the estimation purposes. However, CF is affected by site-specific conditions. The objective of this research is to demonstrate a novel modelling approach that allows incorporating site-specific soil and irrigation water parameters to improve the accuracy of the ECe estimation. A total of 177 soil samples were collected from agricultural soils in the Jordan Valley representing different soil textures, crops and water qualities. ECe, EC 1:5 , clay and sand content, soil texture and saturation percentage (θ SP) were determined. The collected data were used to construct models using three distinct approaches: traditional CF; incorporating θ SP as a surrogate of soil texture to cater the CF to the site-conditions, and Artificial Neural Networks to incorporate site-specific parameters. The neural network model gave the most accurate estimates (R 2 = 0.987, MSE = 2.39) and was able to handle the heteroscedasticity of the data. Meanwhile, the incorporation of θ SP to estimate the CF that best represent the site has shown improved prediction quality over the traditional CF approach as it was more capable of handling the heteroscedasticity of the data. The neural network model allows for the incorporation of location-specific parameters and therefore offers a flexible tool for better management of agricultural soils. Although, this work used a case study location to demonstrate the concepts discussed, the approach is generalizable and can be easily adapted to other locations.
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Soil water infiltration is a critical process in the soil water cycle and agricultural practices, especially when wastewater is used for irrigation. Although research has been conducted to evaluate the changes in the physical and chemical... more
Soil water infiltration is a critical process in the soil water cycle and agricultural practices, especially when wastewater is used for irrigation. Although research has been conducted to evaluate the changes in the physical and chemical characteristics of soils irrigated by treated wastewater, a quantitative analysis of the effects produced on the infiltration process is still lacking. The objective of this study is to address this issue. Field experiments previously conducted on three adjacent field plots characterized by the same clayey soil but subjected to three different irrigation treatments have been used. The three irrigation conditions were: non-irrigated (natural conditions) plot, irrigated plot with treated wastewater for two years, and irrigated plot with treated wastewater for five years. Infiltration measurements performed by the Hood infiltrometer have been used to estimate soil hydraulic properties useful to calibrate a simplified infiltration model widely used under ponding conditions, that were existing during the irrigation stage. Our simulations highlight the relevant effect of wastewater usage as an irrigation source in reducing cumulative infiltration and increasing overland flow as a result of modified hydraulic properties of soils characterized by a lower capacity of water drainage. These outcomes can provide important insights for the optimization of irrigation techniques in arid areas where the use of wastewater is often required due to the chronic shortage of freshwater.
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Improving soil properties, especially in arid and semiarid regions, is an urgent need for sustainable food production. This study aims to evaluate the effect of applying two types of anionic polyacrylamide polymers (PAMs) with different... more
Improving soil properties, especially in arid and semiarid regions, is an urgent need for sustainable food production. This study aims to evaluate the effect of applying two types of anionic polyacrylamide polymers (PAMs) with different molecular weights on: (1) soil aggregate stability, (2) infiltration rate and (3) saturated hydraulic conductivity of sandy loam soil and introduce a novel modelling approach to predict the effect of PAM addition on the mentioned soil properties. Polymers were applied at five different concentrations; 0, 100, 250, 500 and 1000 mg L − 1. Direct positive relations between the concentrations of PAM (low and high molecular weight) and saturated hydraulic conductivity and infiltration rate were observed. Nevertheless, the relations were more pronounced in case of low molecular weight PAM. The difference between the effect of the two PAMs on infiltration rate was statistically significant at α = 0.05. On the other hand, the differences were not significant except for the 1000 mg L − 1 concentration in case of saturated hydraulic conductivity. Meanwhile, concentration has an effect on increasing soil aggregate stability only in case of low molecular weight PAM. At the concentration 1000 mg L-1 of low molecular weight PAM, aggregate stability and saturated hydraulic conductivity increased 3-fold while infiltration rate increased by more than 7-fold compared to the control. It is hypothesized that the change in the mentioned properties is correlated to the amount of PAM adsorbed by the soil and hence they can be used as surrogate parameters of adsorption. Modified versions of the Langmuir and Freundlich isotherm equations were used to model the change in aggregate stability and saturated hydraulic conductivity in response to the PAM concentration. The pseudo-first and second kinetics models were applied to predict the change in infiltration rate. The models showed excellent fit to the experimental data, thus supporting our hypothesis. The results suggest that low molecular weight PAM is more efficient in improving the physical properties of sandy loam soil. The modelling approach presented in this work may be extended to other types of soil. Other isotherm models may be used to predict the response of soil to PAM concentration where the Langmuir or Freundlich isotherms do not apply. This modelling approach provides land managers with a decision support tool to optimize PAM application.
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Biochar has been explored as a sorbent for contaminants, soil amendment and climate change mitigation tool through carbon sequestration. Through the optimization of the pyrolysis process, biochar can be designed with qualities to suit the... more
Biochar has been explored as a sorbent for contaminants, soil amendment and climate change mitigation tool through carbon sequestration. Through the optimization of the pyrolysis process, biochar can be designed with qualities to suit the intended uses. Biochar samples were prepared from four particle sizes (100-2000 µm) of three different feedstocks (oak acorn shells, jift and deseeded carob pods) at different pyrolysis temperatures (300-600 °C). The effect of these combinations on the properties of the produced biochar was studied. Biochar yield decreased with increasing pyrolysis temperature for all particle sizes of the three feedstocks. Ash content, fixed carbon, thermal stability, pH, electrical conductivity (EC), specific surface area (SSA) of biochar increased with increasing pyrolysis temperature. Volatile matter and pH value at the point of zero charge (pHpzc) of biochar decreased with increasing pyrolysis temperature. Fourier-transform infrared spectroscopy (FTIR) analysis indicated that the surface of the biochar was rich with hydroxyl, phenolic, carbonyl and aliphatic groups. Methylene blue (MB) adsorption capacity was used as an indicator of the quality of the biochar. Artificial neural networks (ANN) model was developed to predict the quality of the biochar based on operational conditions of biochar production (parent biomass type, particle size, pyrolysis temperature). The model successfully predicted the MB adsorption capacity of the biochar. The model is a very useful tool to predict the performance of biochar for water treatment purposes or assessing the general quality of a design biochar for specific application.
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Olive oil industry generates a considerable amount of olive mill wastewater (OMW) each year, which increases the difficulties for successful processing and disposing. A possible and potential alternative is controlled application of OMW... more
Olive oil industry generates a considerable amount of olive mill wastewater (OMW) each year, which increases the difficulties for successful processing and disposing. A possible and potential alternative is controlled application of OMW into the land. In these two fields' experiments, we investigated a sustainable controlled land application of OMW to enhance soil properties and improve barley production under rainfed conditions. OMW was spread at five application rates (20, 40, 60, 80, and 120 m 3 ha −1) in addition to the control at two sites, Rabba and Ghweer. The physico-chemical characterizations of OMW were determined throughout the season. Physicochemical properties of soil were measured after 2 weeks of OMW spreading after planting and after barley harvest. Leaf nutrient content as well as other growth performance has been measured. The results of this study showed no harmful effect of OMW application for all application rates on growth parameters of barley as well as soil properties at both locations. Under all application rates, OMW has increased soil organic matter and nutrient contents, which could reduce the use of chemical fertilizer. There was a significant increase in barley growth in OMW treatments for dry weight (DM) (14 and 22%), biological yield (BYLD) (49 and 34%), grain yield (GYLD) (41 and 47%), and straw yield (SYLD) (55 and 31%) at Rabba and Ghweer sites, respectively. The results exhibited the benefit of controlled application of OMW. However, long-term effect of OMW application needs more study, and local legislative is necessary.
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The olive mill wastewater (OMW) properties impose substantial practical and fiscal difficulties for effective management and dumping. A feasible and practical option is a regulated spreading of OMW into the soil. This study aimed to... more
The olive mill wastewater (OMW) properties impose substantial practical and fiscal difficulties for effective management and dumping. A feasible and practical option is a regulated spreading of OMW into the soil. This study aimed to investigate the sustainable reuse of OMW through land application to enhance soil quality and wheat growth performance under rain-fed conditions. OMW was spread at 20, 40, 60, 80, and 120 m 3 ha −1 at two sites. Soil physical and chemical properties were measured after OMW application and after harvest. Wheat growth performance and leaf nutrient content were determined. This study revealed no deleterious influence of OMW application on soil properties and wheat growth at the two locations for all OMW application doses. The OMW land spreading improved significantly wheat growth by increasing the biological yield (BYLD) (8.4 to 36.5%), grain yield (GYLD) (20.1 to 79.4%), and harvest index (HI) (4.2 to 60.2%). Based on the measured soil chemical parameters and wheat grain yield, we can suggest that OMW application rate at 60 m 3 ha −1 could improve significantly wheat growth without significant negative impact on soil properties. In conclusion, we recommend using OMW as suggested in this study for wheat. However, still the long-term application of OMW assessment and local legislative adaptation of saving use are necessary.
The effect of irrigation with treated wastewater (TWW) on soil physico-chemical and hydraulic properties was evaluated in this study. Field treatments were: non-irrigated (rain-fed) plot (control), rain-fed plot for the first three years... more
The effect of irrigation with treated wastewater (TWW) on soil physico-chemical and hydraulic properties was evaluated in this study. Field treatments were: non-irrigated (rain-fed) plot (control), rain-fed plot for the first three years and irrigated with TWW for the last two years (2 yr) and plot irrigated with TWW for five years (5 yr). Soil samples were collected from two depth intervals (0–15 and 15–30 cm) in five replicates. Irrigation with TWW significantly increased aggregate stability (AS), exchangeable sodium percentage (ESP), organic matter (OM), and electrical conductivity (EC). Both hydraulic conductivity (HC) and cumulative infiltration (F(t)) were decreased significantly with TWW use and period of application. Moreover, reduction of HC at different tension revealed that pore clogging occurred at both, macro and micro scale. Scanning electron microscopy (SEM) images showed that soil pores were clogged partially and/or fully as a result of suspended particulates and organic matter. Enhanced AS of treated areas indicated that infiltration was more affected by pore clogging than soil dispersion and swelling.
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Soil structure directly determines important soil physical properties including porosity, hydraulic conductivity, water retention, and mechanical strength and indirectly influences most biological and chemical processes that occur in and... more
Soil structure directly determines important soil physical properties including porosity, hydraulic conductivity, water retention, and mechanical strength and indirectly influences most biological and chemical processes that occur in and around soil. The interaction of environmental and biotic agents influences the physical condition of the soil, particularly through soil structural evolution. Wetting and drying cycles are important environmental processes known to enhance aggregation, while clay minerals, sesquioxides and soil organic matter (SOM) are the soil solids most involved in soil structural development. We hypothesize that drying of capillary water transports suspended and/or dissolved cementing agents toward inter-particle contacts and eventually deposits part of the colloidal mass forming inter-particle bonds. Here, we will show the role of wetting and drying cycles on soil aggregation and stabilization and how these cycles transport and deposit organic cementing agents ...
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ABSTRACT The configuration, molecular weight and the type and charge of functional groups often have a strong effect on adhesion of Extracellular Polysaccharides (EPS) to solid surfaces. Our hypothesis is that the EPS with higher... more
ABSTRACT The configuration, molecular weight and the type and charge of functional groups often have a strong effect on adhesion of Extracellular Polysaccharides (EPS) to solid surfaces. Our hypothesis is that the EPS with higher molecular weight will be more associated with sand as compared to those with a low molecular weight. In this study, we investigated the association of anionic EPS by sand of six size fractions. The association experiment was carried out at different time, initial concentrations, and sorbent concentrations. EPS concentrations were determined by Sulfuric Acid-UV method. Preliminary results indicate that increasing the concentration will lead to the formation of longer molecules. Therefore, more association with sand will be occurred until critical length is reached where increasing the length of the molecules will adversely affect the association.
ABSTRACT In recent years, significant amount of literature showed that rhizosphere's physical and chemical properties markedly differ from those of the bulk soil. Plants invest large portion of their photosynthetic carbon in... more
ABSTRACT In recent years, significant amount of literature showed that rhizosphere's physical and chemical properties markedly differ from those of the bulk soil. Plants invest large portion of their photosynthetic carbon in developing root architecture that optimally exploits water and nutrient distributions in the soil. There is indirect evidence suggesting that these exudates play a major role in altering the of the soil water retention properties. In this study, we investigated the role of root exudates on rhizosphere water dynamics using analog system. Glass beads were used to represent loose soil and dilute solutions of polygalacutronic acid (PGA) to mimic exudates (0, 1, 5, 15 and 29 g/L). The samples were subjected to periods of drying and subsequent equilibration. At each stage, the water potential was measured using WP4C Dewpoint PotentiaMeter. On the other hand, sand samples were saturated with PGA at the same concentration used to study the effect of exudates on water evaporation rate. The effect of root exudates on soil water retention can be attributed to at least two factors. The most widely speculated effect is through enhanced of soil aggregation. This effect is primarily due to capillary adhesion in fine pores within aggregates and is consistent with visual observation of pronounced aggregation in many rhizosphere soils. The second factor is related to osmotic effect of the exudate solution. Our observations show that the capillary effect is mostly limited to higher water potential regime (> -1 bar suction). Whereas the osmotic effect dominates in <- 1 bar suction. At the same time, the osmotic potential results from these organic exudates play an important role in reducing the evaporation rate. These results will provide direct quantitative evidence of how rhizosphere organic matter helps plant-soil relations.
ABSTRACT Soil structure influences many soil properties including aeration, water retention, drainage, bulk density, and resistance to erosion and indirectly influences most biological and chemical processes that occur in and around soil.... more
ABSTRACT Soil structure influences many soil properties including aeration, water retention, drainage, bulk density, and resistance to erosion and indirectly influences most biological and chemical processes that occur in and around soil. In nature, soil is continually exposed to wetting (e.g., rainfall and diffusive flow) and drying (e.g., evaporation, diffusive flow and plant uptake). These natural wetting and drying cycles of soils are physical events that profoundly affect the development of soil structure, aggregate stability, carbon (C) flux and mineralization. We hypothesize that drying of capillary water transports suspended and/or dissolved cementing agents toward inter-particle contacts and eventually deposits part of the colloidal mass forming inter-particle bonds. Here, we will show the role of wetting and drying cycles on soil aggregation and stabilization and how these cycles transport and deposit organic cementing agents at the inter-particle contact. We found that aggregates of sand and silt particles can be formed by subjecting loose particles to wetting-drying cycles in the presence of dilute solutions of organic matter that mimic root or microbial exudates. Moreover, majority of the organic matter was deposited in the contact region between the sand particles, where the water accumulates during drying. The model predictions and aggregate stability measurements are supported by scanning electron micrographs that clearly show the process of aggregate formation.
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The removal of sodium salts from saline soils by salt tolerant crops, as alternative for costly chemical amendments, has emerged as an efficient low cost technology. Lysimeter experiments were carried out on a highly saline sodic soil... more
The removal of sodium salts from saline soils by salt tolerant crops, as alternative for costly chemical amendments, has emerged as an efficient low cost technology. Lysimeter experiments were carried out on a highly saline sodic soil (ECe = 65.3 dS m −1 , ESP = 27.4, CEC = 47.9 cmole (+) kg −1 , and pH = 7.7) and irrigated with canal water (EC = 2.2 dSm −1 , SAR = 4.8) to investigate reclamation efficiency under four different treatments: control (no crop and no gypsum application) (C), gypsum application equivalent to 100% gypsum requirement (G 100), planting sea orach (Atriplex halimus) as phytoremediation crop (Cr), planting sea orach with gypsum application equivalent to 50% gypsum requirement (CrG 50). Soil salinity (ECe) and exchangeable sodium percentage (ESP) were significantly reduced compared to the control. Average ESP and ECe (dS m −1) in the top layer were 9.1, 5.8 (control), 4.8, 3.7 (Cr), 3.3, 3.9 (CrG 50), and 3.8, 3.1 (G 100), respectively. Atriplex halimus can be recommended as phytoremediation crop to reclaim highly saline sodic clay loam soils.
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Olive-oil production has a vital impact on the socioeconomic development in most Mediter-ranean countries, where 97.5 % of the world oil is produced. However, the olive-oil extraction process generates considerable quantities of an... more
Olive-oil production has a vital impact on the socioeconomic development in most Mediter-ranean countries, where 97.5 % of the world oil is produced. However, the olive-oil extraction process generates considerable quantities of an agro-industrial effluent, olive mill wastewater (OMW), which has negative impact on the environment and biological life. The objective of this study was to evaluate the potential use of OMW treated by different technologies in irrigation and determine its effect on the plant growth and soil quality parameters. Different technologies were used to treat the OMW, the resultant treated OMW was used to irrigate the maize planted in the pot experiment. The results indicated that UOMW increased soil salinity and reduced plant growth, while the treated OMW by different technologies improved plant growth and resulted in lower soil pH. The impact on other soil properties varied depending on the techniques used for treatments. Although treated OMW enhanced plant growth compared with the untreated, the plant growth remained lower than that obtained using the potable water with fertilizers, indicating lack of some essential plant nutrients.
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Olive-mill wastewater (OMW) is a by-product effluent of olive oil extraction process that is produced in large amount in the Mediterranean region. OMW is believed to induce phytotoxic effect on organisms including seed germination and... more
Olive-mill wastewater (OMW) is a by-product effluent of olive oil extraction process that is produced in large amount in the Mediterranean region. OMW is believed to induce phytotoxic effect on organisms including seed germination and plant growth. The objective of this study was to evaluate the impact of untreated and treated OMW with different techniques on seed germination of barley (Hordeum vulgare L.). The following treatments were investigated: (1) tap water (control); (2) OMW treated by aerobic biological technology in a Jacto Reactor (JR); (3) OMW treated by solar fenton oxidation (SFO); (4) OMW treated by microfiltration followed by nanofiltration (MF+NF); (5) OMW treated by microfiltration followed by reverse osmosis (MF+RO) process; (6) diluted OMW with tap water (25 % OMW); (7) diluted OMW with tap water (50 % OMW); (8) diluted OMW with tap water (75 % OMW); and (9) untreated OMW (100 % OMW). A germination test was conducted in an incubator at temperature of 23 • C. In each petri dish, a filter paper was mounted and ten seeds of barley were placed on the filter paper. Five milliliter of water were added to each petri dish. The seed germination was determined by counting the number of germinated seeds to calculate the percentage of germination (G %). Germination rate index (GRI), seed vigor index (SVI), and phytotoxic-ity index (PI) were also calculated. Then, the dry weights and lengths of the shoots and the roots of the germinated seeds were measured. The results show that 100, 75, and 50 %OMW were very phytotoxic and completely prohibited seed germination. However, phytotoxicity decreased significantly following treatments of OMW with all techniques investigated and by the 25 % OMW dilution, as results of removing the phenols and other phytotoxic organic compounds from the OMW or by diluting it. This was evidenced by relative enhancement of the dry weights and lengths of shoot and root as well as the G %, GRI, SVG, and PI. It was concluded that if OMW will be used for irrigating crops, it has to be first treated or diluted with tap water at a ratio of 1:3 OMW:water at least. The most efficient treatment techniques in reducing the phytotoxicity of OMW were the MF+RO, followed by SFO and JR.
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Accumulation of metals in cultivated crops is considered one of the primary constraints to irrigated agriculture. A greenhouse pot experiment was carried out to study the effects of irrigation with elevated cad-mium (Cd) and a combination... more
Accumulation of metals in cultivated crops is considered one of the primary constraints to irrigated agriculture. A greenhouse pot experiment was carried out to study the effects of irrigation with elevated cad-mium (Cd) and a combination of cadmium and zinc (Zn) levels on Cd uptake, translocation, and productivity of tomato (Solanum lycopersicum) plants. Tomato seedlings were grown in 3-kg pots irrigated for three months until maturity. Treatments were as follows: pots irrigated with fresh water containing Cd concentrations (0, 0.01, 0.04, 0.16, 0.64, 2.54 mg L −1), and pots irrigated with a combination of Cd + Zn concentrations (0 + 0, 0.01 + 2, 0.04 + 8, 0.16 + 32, 0.64 + 128, and 2.56 + 256 mg L −1). Cadmium and Zn concentration in soil and plant parts (root, shoot, and fruit) increased with increasing metal dose in irrigation water. Results also showed that Cd accumulation in the fruit was much lower than in the shoot indicating lower Cd transfer from soil to the fruit. Tomato biomass was not affected by treatments even at the highest metal dose. The uptake of Cd in tomato fruit ranged from 0.5 to 2.0 and from 0.3 to 1 mg kg −1 , in single and combination treatments, respectively. Cadmi-um in fruit exceeded the permissible limit at 0.04 and 0.16 + 32 mg L −1 in Cd and Cd + Zn treatments, respectively. Therefore these levels could be considered as a threshold for tomato cultivation in clayey soil.
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Exploring the genetic diversity among plant accessions is important for conserving and managing plant genetic resources. In the current study, a collection of forty-six tomato accessions from Jordan were evaluated based on their... more
Exploring the genetic diversity among plant accessions is important for conserving and managing plant genetic resources. In the current study, a collection of forty-six tomato accessions from Jordan were evaluated based on their performance and their morpho-physiological, in addition to molecularly characterizing to detect genetic diversity. Tomato accessions seedlings were exposed to drought stress with 70% field capacity and 40% field capacity under field conditions in Jordan. Drought stress had significantly negatively influenced the dry root weight, fresh root weight, root growth rate, fresh shoot weight, dry shoot weight, and shoot growth rate. Moreover, proline content showed a highly significant increase of 304.2% in response to drought stress. The analysis of twenty morphological characters revealed a wide range of variations among tomato accessions. Accessions were screened with fourteen SSR primers; six primers were informative to explain the genetic diversity. Based on re...
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An alternative strategy for saving limited water resources is using treated wastewater (TWW) originating from wastewater treatment plants. However, using TWW can influence soil properties owing to its characteristics compared to... more
An alternative strategy for saving limited water resources is using treated wastewater (TWW) originating from wastewater treatment plants. However, using TWW can influence soil properties owing to its characteristics compared to conventional water resources. Therefore, assessing the effect of TWW on soil properties and soil water infiltration is crucial to maintain sustainable use of TWW and to increase the water use efficiency of the precious irrigation water. Moreover, several studies were carried out to assess the performance of infiltration models. However, few studies evaluate infiltration models under the use of treated wastewater. Therefore, this study aims to assess the effect of TWW irrigation on soil properties after 2 and 5 years and to evaluate five classical infiltration models with field data collected from soil irrigated by treated wastewater for their capability in predicting soil water infiltration. This study revealed that using TWW for irrigation affects significa...
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Most countries, particularly those in arid and semi-arid regions, are grappling with important agricultural production issues that influenced by rapid population growth and limited water resources. The application of soil additives to... more
Most countries, particularly those in arid and semi-arid regions, are grappling with important agricultural production issues that influenced by rapid population growth and limited water resources. The application of soil additives to improve soil properties and water usage productivity has sparked the most attention, particularly in arid and semi-arid environments. The goal of this study was to assess the effect of hydrogel on soil physical properties and plant growth parameters using sandy and silty clay loam soils. Laboratory experiments were implemented using ten different concentrations of hydrogel based on the percentage of the added hydrogel (0, 0.02, 0.04, 0.07, 0.09, 0.11, 0.16, 0.22, 0.27 and 0.33% (w/w) hydrogel/soil) to assess its effect on soil physical and hydraulic properties. Moreover, a greenhouse pot experiment was conducted using four hydrogel concentrations of 0, 0.25, 0.5, and 1% (w/w) on Zea mays as a model plant to assess its effect on plant growth parameters. Results revealed that the greatest improvement in soil aggregate percentage was 35% with 0.27% hydrogel concentration whereas, 0.33% hydrogel concentration increased the soil available water by 49%. Moreover, water use efficiency was increased from 13% to 41% for sandy soil and from 35% to 67% for silty clay loam soil. In addition, when compared to the control, both soils' water use efficiency and corn growth rose. In agriculture, hydrogel can improve soil physical properties while also boosting water use efficiency and plant development parameters in dry and semi-arid areas.
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The aim of this study was to assess the potential use of biochar derived from olive pruning to enhance soil properties and tomato and bell pepper plant growth and yield performance in arid environments. Biochar was prepared from olive... more
The aim of this study was to assess the potential use of biochar derived from olive pruning to enhance soil properties and tomato and bell pepper plant growth and yield performance in arid environments. Biochar was prepared from olive tree–pruning residues. The biochar was applied to field experiments of tomato and bell pepper plants at five application rates (0, 8, 16, 30, and 40 t ha−1). Relative water content (RWC), leaf chlorophyll, and leaf nutrient (nitrogen (N), phosphorus (P), and potassium (K)) contents were measured. The total yield was determined for each treatment. Fruit nutrient contents were determined in selected fruit samples. Soil samples were collected from each treatment at the middle and end of the experiment for physical and chemical analysis. All experiments were conducted in triplicate. The application of biochar at rates of 8 and 16 t ha−1 enhanced tomato and bell pepper growth; however, application of 30 and 40 t ha−1 adversely affected tomato and bell pepper growth. Nutrient analysis showed that N, P, and K concentrations in leaves and fruits were higher in plants treated with 8 and 16 t ha−1 of biochar than in biochar treatments of 30 and 40 t ha−1. Higher biochar application rates increased soil pH and EC by 1.4% and 12.3% (8 t ha−1) to 7.3% and 107.8% (40 t ha−1), respectively. A biochar application rate of 8 t ha−1 is recommended as an optimal rate to enhance soil fertility for tomato and bell pepper production systems in arid environments.
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Abstract Soil salinity is best estimated by saturated paste extract (ECe), the most reliable monitoring method to assess plant growth that is directly related to the field water content. However, this procedure is laborious and... more
Abstract Soil salinity is best estimated by saturated paste extract (ECe), the most reliable monitoring method to assess plant growth that is directly related to the field water content. However, this procedure is laborious and time-consuming, therefore, more convenient methods such as 1:5 soil: water extract is commonly used to estimate the ECe. Traditionally, a conversion factor (CF) based on a linear correlation between the diluted extract and ECe is employed for the estimation purposes. However, CF is affected by site-specific conditions. The objective of this research is to demonstrate a novel modelling approach that allows incorporating site-specific soil and irrigation water parameters to improve the accuracy of the ECe estimation. A total of 177 soil samples were collected from agricultural soils in the Jordan Valley representing different soil textures, crops and water qualities. ECe, EC1:5, clay and sand content, soil texture and saturation percentage (θSP) were determined. The collected data were used to construct models using three distinct approaches: traditional CF; incorporating θSP as a surrogate of soil texture to cater the CF to the site-conditions, and Artificial Neural Networks to incorporate site-specific parameters. The neural network model gave the most accurate estimates (R2 = 0.987, MSE = 2.39) and was able to handle the heteroscedasticity of the data. Meanwhile, the incorporation of θSP to estimate the CF that best represent the site has shown improved prediction quality over the traditional CF approach as it was more capable of handling the heteroscedasticity of the data. The neural network model allows for the incorporation of location-specific parameters and therefore offers a flexible tool for better management of agricultural soils. Although, this work used a case study location to demonstrate the concepts discussed, the approach is generalizable and can be easily adapted to other locations.
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Olive-oil production has a vital impact on the socioeconomic development in most Mediterranean countries, where 97.5 % of the world oil is produced. However, the olive-oil extraction process generates considerable quantities of an... more
Olive-oil production has a vital impact on the socioeconomic development in most Mediterranean countries, where 97.5 % of the world oil is produced. However, the olive-oil extraction process generates considerable quantities of an agro-industrial effluent, olive mill wastewater (OMW), which has negative impact on the environment and biological life. The objective of this study was to evaluate the potential use of OMW treated by different technologies in irrigation and determine its effect on the plant growth and soil quality parameters. Different technologies were used to treat the OMW, the resultant treated OMW was used to irrigate the maize planted in the pot experiment. The results indicated that UOMW increased soil salinity and reduced plant growth, while the treated OMW by different technologies improved plant growth and resulted in lower soil pH. The impact on other soil properties varied depending on the techniques used for treatments. Although treated OMW enhanced plant growth compared with the untreated, the plant growth remained lower than that obtained using the potable water with fertilizers, indicating lack of some essential plant nutrients.
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Accumulation of metals in cultivated crops is considered one of the primary constraints to irrigated agriculture. A greenhouse pot experiment was carried out to study the effects of irrigation with elevated cadmium (Cd) and a combination... more
Accumulation of metals in cultivated crops is considered one of the primary constraints to irrigated agriculture. A greenhouse pot experiment was carried out to study the effects of irrigation with elevated cadmium (Cd) and a combination of cadmium and zinc (Zn) levels on Cd uptake, translocation, and productivity of tomato (Solanum lycopersicum) plants. Tomato seedlings were grown in 3-kg pots irrigated for three months until maturity. Treatments were as follows: pots irrigated with fresh water containing Cd concentrations (0, 0.01, 0.04, 0.16, 0.64, 2.54 mg L−1), and pots irrigated with a combination of Cd + Zn concentrations (0 + 0, 0.01 + 2, 0.04 + 8, 0.16 + 32, 0.64 + 128, and 2.56 + 256 mg L−1). Cadmium and Zn concentration in soil and plant parts (root, shoot, and fruit) increased with increasing metal dose in irrigation water. Results also showed that Cd accumulation in the fruit was much lower than in the shoot indicating lower Cd transfer from soil to the fruit. Tomato biomass was not affected by treatments even at the highest metal dose. The uptake of Cd in tomato fruit ranged from 0.5 to 2.0 and from 0.3 to 1 mg kg−1, in single and combination treatments, respectively. Cadmium in fruit exceeded the permissible limit at 0.04 and 0.16 + 32 mg L−1 in Cd and Cd + Zn treatments, respectively. Therefore these levels could be considered as a threshold for tomato cultivation in clayey soil.
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A new UV spectrophotometry based method for determining the concentration and carbon content of carbohydrate solution was developed. This method depends on the inherent UV absorption potential of hydrolysis byproducts of carbohydrates... more
A new UV spectrophotometry based method for determining the concentration and carbon content of carbohydrate solution was developed. This method depends on the inherent UV absorption potential of hydrolysis byproducts of carbohydrates formed by reaction with concentrated sulfuric acid (furfural derivatives). The proposed method is a major improvement over the widely used Phenol-Sulfuric Acid method developed by DuBois, Gilles, Hamilton, Rebers, and Smith (1956). In the old method, furfural is allowed to develop color by reaction with phenol and its concentration is detected by visible light absorption. Here we present a method that eliminates the coloration step and avoids the health and environmental hazards associated with phenol use. In addition, avoidance of this step was shown to improve measurement accuracy while significantly reducing waiting time prior to light absorption reading. The carbohydrates for which concentrations and carbon content can be reliably estimated with this new rapid Sulfuric Acid-UV technique include: monosaccharides, disaccharides and polysaccharides with very high molecular weight.