The transfer of 226Ra from irrigation water to basil crops was studied in field conditions. A ded... more The transfer of 226Ra from irrigation water to basil crops was studied in field conditions. A dedicated basil plot was established and divided into test and control subplots irrigated with water having high (2.1 Bq L-1) and low (0.05 Bq L-1) activity concentrations of 226Ra, respectively. The experiment was performed over a period of 18 months during the autumn, winter and spring seasons, altogether eight cycles of growth and harvest. The activity concentration of 226Ra in basil grown in the test subplots was found to increase from a value of 0.6 Bq kg-1 up to 5.1 Bq kg-1 with successive cycles, compared to a mean value of 0.2 Bq kg-1 for basil grown in the control subplots. The increase in activity concentration of 226Ra in basil grown in the test subplots is mainly attributed to its build-up in the soil in which the level of 226Ra was found to increase by ~ 40%. The effective uptake of 226Ra from the irrigation water (via soil) by the basil plants was found to be approximately 0.4...
Abstract Dryland agriculture has extensive impacts on surrounding ecosystems through its unintent... more Abstract Dryland agriculture has extensive impacts on surrounding ecosystems through its unintentional provision of food and water resources to local wildlife. We analyzed the response of a predator community of jackals, wolves and foxes to land-management choices, and how that response in turn affects native gazelles and Acacia vegetation in the Arava Valley of Israel. This hyperarid region is characterized by contrasting regimes comprising privatized (Moshavim) and communal (Kibbutzim) agricultural settlements, which provides ideal conditions for evaluating how land-management differences translate into crop choices, affecting resource availability and ecosystem changes. Integrating multi-year field observations of predators and gazelles with agricultural datasets, we show that shifts in land-use strategies have cascading ecological impacts. This is evident in the association of date orchards, an expanding land use especially in Kibbutzim, with shifts in the geographical and seasonal distributions of predators. Increased predator presence due to resource availability has displaced gazelles farther from settlements, subsequently impacting Acacia seed dispersal and recruitment. Considering the global expansion of dryland agriculture, the evidence of such socio-ecological cascading effects suggests the necessity to approach agricultural management at the landscape scale in desert regions.
Abstract The date palm (Phoenix dactylifera), an important agricultural crop in arid and semi-ari... more Abstract The date palm (Phoenix dactylifera), an important agricultural crop in arid and semi-arid areas around the Mediterranean Sea, has high nutritional, cultural, and economic values. Date palm cultivation in Israel is practiced in the arid and hyper-arid Jordan and Arava Valleys and is associated with high water and nitrogen (N) fertilization inputs, with rates of up to ~170 m3 water and ~6 kg N per full-grown tree annually, on average. While the palm’s water needs and budget have been intensively studied, the fate of applied N has received little attention to date. Understanding this fate is especially important since high fertilization rates of ~740 kg N ha−1 may have deleterious effects on the environment. Specifically, soil emissions of nitrous oxide (N2O) and leaching of nitrate (NO3-) are of major concern, due to their impact on climate change and groundwater contamination. We have measured the effect of four levels of N fertigation (fertilization + irrigation), between 0 and 2.55 kg N tree−1 yr−1, on N2O and NO3- fluxes during an annual growth season in a three-year-old date palm orchard located in Israel’s hyper-arid Arava Valley. We used static chambers for soil N2O flux estimations and measured drainage water NO3- concentrations at a 60-cm depth, together with a Cl- mass-balance-based water budget to estimate the NO3- leaching. We observed trivial soil N2O emissions of up to ~0.02% of applied N, while NO3- leaching was estimated to be as high as 36%. Dry areas between the trees, which did not receive any fertilization or irrigation, exhibited even lower N2O emissions than the irrigated areas. Inorganic N, however, accumulated during the dry months in the upper layer of the soil and was later lost at the onset of the winter rains. Our results provide the first-ever estimations of the potential environmental impact of date palm plantations in Israel and the Mediterranean Sea Basin.
There are gaps in our knowledge of the effects of irrigation water quality and amount on yield an... more There are gaps in our knowledge of the effects of irrigation water quality and amount on yield and postharvest quality of pepper fruit (Capsicum annuum L.). We studied the effects of water quality and quantity treatments on pepper fruits during subsequent simulated storage and shelf-life. Total yield decreased with increasing water salinity, but export-quality yield was not significantly different in fruits irrigated with water of either 1.6 or 2.8 dS/m, but there was a 30–35% reduction in export-quality yield following use of water at 4.5 dS/m. Water quantity hardly affected either total or export-quality yield. Water quality but not quantity significantly affected fruit weight loss after 14 days at 7 °C plus three days at 20 °C; irrigation with water at 2.8 dS/m gave the least weight loss. Fruits were significantly firmer after irrigation with good-quality water than with salty water. The saltier the water, the higher was the sugar content. Vitamin C content was not affected by wa...
Journal of Agricultural and Food Chemistry, Oct 1, 2009
The well-established health beneficial value of pomegranate juice is leading to increased demand ... more The well-established health beneficial value of pomegranate juice is leading to increased demand for pomegranate products and to the expansion of pomegranate orchards worldwide. The current study describes differences in the chemical composition of major ingredients of the arils and peels of 11 accessions grown in Mediterranean and desert climates in Israel. In most of the accessions, the levels of antioxidant activity and content of total phenolics, total anthocyanins, total soluble solids, glucose, fructose, and acidity were higher in the aril juice of fruit grown in the Mediterranean climate compared to those grown in the desert climate. However, the peels of fruit grown in the desert climate exhibited higher antioxidant activity, and the levels of total phenolics, including the two hydrolyzable tannins, punicalagin and punicalin, were higher compared to those in the peels of fruit grown in the Mediterranean climate. The results indicate that environmental conditions significantly affect pomegranate fruit quality and health beneficial compounds.
Three experiments were carried out using nine lysimeters filled with typical Southern Arava soil.... more Three experiments were carried out using nine lysimeters filled with typical Southern Arava soil. Each lysimeter was equipped with a scale for continuous weighing which established a highly accurate water and Ra mass balance. The experiments involved four crops; the irrigation scheme for each experiment and each lysimeter is shown in Table 1. 2 kg of plant tissues were oven-dried at 105 0 C for 24 h, and immediately pyrolized at 400 0 C. The samples were kept in a sealed standard container for three weeks to achieve secular equilibrium of the Ra and its decay products. Water samples were filtered through MnO 2 coated fibers. The fibers were then transferred into a sealed standard container and counted by gamma spectrometry. Soil samples excavated 15, 30, 45 and 60 cm underneath the stem were analyzed for profile distribution of Ra. Isotherms of Ra adsorption were constructed for the Arava soil. The soil was equilibrated with solutions containing 0, 1.7, 37.8, 1858, 4413, 5939 and 37763 Bq•l-1. 10-g soil triplicate samples with 20 ml of solution were mixed in 50-ml polypropylene centrifuge tubes and shaken for 24 h at 25 0 C. After equilibration, suspensions were centrifuged, filtered, and tested for pH and Ra. Measurements of the radium activity concentrations in soil, water and plant tissues samples were performed by standard gamma spectrometry methods. The kinetics of Ra distribution in soil and in drainage water was modeled by means of the HYDRUS 1-D software package (Simunek et al., 1998).
High radium concentrations may play a key role in the potential exploitation and utilization of g... more High radium concentrations may play a key role in the potential exploitation and utilization of groundwater for drinking water as well as for agricultural purposes. Radionuclides of natural origin, including radium, are present in all foodstuffs at varying degrees. In essence, the doses from natural radionuclides are not worthy to control since the concentrations are mostly low and the resources
The well-established health beneficial value of pomegranate juice is leading to increased demand ... more The well-established health beneficial value of pomegranate juice is leading to increased demand for pomegranate products and to the expansion of pomegranate orchards worldwide. The current study describes differences in the chemical composition of major ingredients of the arils and peels of 11 accessions grown in Mediterranean and desert climates in Israel. In most of the accessions, the levels of antioxidant activity and content of total phenolics, total anthocyanins, total soluble solids, glucose, fructose, and acidity were higher in the aril juice of fruit grown in the Mediterranean climate compared to those grown in the desert climate. However, the peels of fruit grown in the desert climate exhibited higher antioxidant activity, and the levels of total phenolics, including the two hydrolyzable tannins, punicalagin and punicalin, were higher compared to those in the peels of fruit grown in the Mediterranean climate. The results indicate that environmental conditions significantly affect pomegranate fruit quality and health beneficial compounds.
The Journal of Horticultural Science and Biotechnology
Off-types are quite common among tissue culture-produced date palm trees. The present study chara... more Off-types are quite common among tissue culture-produced date palm trees. The present study characterises a low fruit setting phenotype, found widely among tissue culture-produced date palms of the cultivar 'Barhee'. Most flowers in such trees turn into parthenocarpic fruitlets having three carpels. In severe cases, supernumerary carpels are formed. Other flower abnormalities include distortions of carpels and stigmas. The phenotype is alleviated in older trees, with about 50% of trees reverting to normal within 10 years from planting. Many flowers on the abnormal trees have impaired pollen tube elongation, with growth being limited to the stigma or to regions near its point of joining the carpel. Directional growth of pollen tubes ceases and tubes grow in different directions or stop growing completely. Possible mechanisms for this off-type phenotype, and its resemblance to other cases of somaclonal variation are discussed.
Irrigation is essential in arid regions to increase crop production. The combination of global ne... more Irrigation is essential in arid regions to increase crop production. The combination of global necessity to increase production of food and fiber with increasing water scarcity has led to utilization of water with high concentrations of salts for crop irrigation, particularly in arid and semi-arid regions.
International Journal of Postharvest Technology and Innovation, 2014
Irrigation water salinity effects on colour and health ingredients in the pomegranate peel were s... more Irrigation water salinity effects on colour and health ingredients in the pomegranate peel were studied in two accessions, 'Wonderful' and 'SP-2', grown under a wide range of salinities, 1.2 to 9 dS m -1 . Ripe fruit peels were analysed for phenolics and anthocyanins composition, and antioxidative capacity. Total phenolics concentration and antioxidative capacity were determined by the Folin-Ciocalteau and FRAP assays, respectively. Phenolics and anthocyanins composition was analysed by RP-HPLC. Increased salinity enhanced considerably the overall accumulation of phenolics and anthocyanins, and the antioxidative capacity in both cultivars; the magnitude of the effects was accession dependent. Mono-and di-glucosides of cyanidins, pelargonidins, and delphinidines were detected at proportions that varied with accession and salinity. Increased concentrations of gallotannins, flavonols and ellagic acid derivatives in 'Wonderful', and punicalagins, flavonols and ellagic acid derivatives in 'SP-2' accompanied elevated salinity levels. The results may benefit the pomegranate juice and byproduct valourisation industries, especially in the face of global water quality deterioration.
1] An accessible solution capable of reliably predicting plant-environmental interrelationships f... more 1] An accessible solution capable of reliably predicting plant-environmental interrelationships for variable species, climates, soils, and management options is a necessary tool for creating sustainable agriculture and environmental preservation. A mechanism-based analytical solution, the first of its kind that considers multiple environmental variables and their combined effects on plant response, was developed and tested. Water uptake by plants, water and salt leakage below the roots, and yield are calculated by solving for transpiration in a single mathematical expression according to limitations imposed by root zone salinity and water status. Input variables include the quantity and salinity of applied water, terms for plant sensitivity to salinity and to water stress, potential evapotranspiration, and soil hydraulic parameters. Where water was not limiting, regression of predicted versus measured data resulted in r 2 = 0.96 with slope of 0.937 and intercept of 0.033 (not different from 1 and 0 at 99% confidence), where irrigation varied and salinity was not limiting the r 2 = 0.94 with slope of 0.906 and intercept of 0.044 (not different from 1 and 0 at 99% confidence), where both salinity and water levels varied r 2 = 0.94 with slope of 0.966 and intercept of 0.033 (not different from 1 and 0 at 99% confidence). Application of the model for agricultural and environmental management and economic analysis is discussed. For example, a farmer in the Arava in Israel where irrigation water salinity is high (electrical conductivity of 3 dS m À1 ) cannot expect to reach greater than 70% of the potential yield for a pepper crop with any amount of irrigation. By choosing melon, the farmer can achieve 90% of potential yield with the same quality and quantity of water.
The transfer of 226Ra from irrigation water to basil crops was studied in field conditions. A ded... more The transfer of 226Ra from irrigation water to basil crops was studied in field conditions. A dedicated basil plot was established and divided into test and control subplots irrigated with water having high (2.1 Bq L-1) and low (0.05 Bq L-1) activity concentrations of 226Ra, respectively. The experiment was performed over a period of 18 months during the autumn, winter and spring seasons, altogether eight cycles of growth and harvest. The activity concentration of 226Ra in basil grown in the test subplots was found to increase from a value of 0.6 Bq kg-1 up to 5.1 Bq kg-1 with successive cycles, compared to a mean value of 0.2 Bq kg-1 for basil grown in the control subplots. The increase in activity concentration of 226Ra in basil grown in the test subplots is mainly attributed to its build-up in the soil in which the level of 226Ra was found to increase by ~ 40%. The effective uptake of 226Ra from the irrigation water (via soil) by the basil plants was found to be approximately 0.4...
Abstract Dryland agriculture has extensive impacts on surrounding ecosystems through its unintent... more Abstract Dryland agriculture has extensive impacts on surrounding ecosystems through its unintentional provision of food and water resources to local wildlife. We analyzed the response of a predator community of jackals, wolves and foxes to land-management choices, and how that response in turn affects native gazelles and Acacia vegetation in the Arava Valley of Israel. This hyperarid region is characterized by contrasting regimes comprising privatized (Moshavim) and communal (Kibbutzim) agricultural settlements, which provides ideal conditions for evaluating how land-management differences translate into crop choices, affecting resource availability and ecosystem changes. Integrating multi-year field observations of predators and gazelles with agricultural datasets, we show that shifts in land-use strategies have cascading ecological impacts. This is evident in the association of date orchards, an expanding land use especially in Kibbutzim, with shifts in the geographical and seasonal distributions of predators. Increased predator presence due to resource availability has displaced gazelles farther from settlements, subsequently impacting Acacia seed dispersal and recruitment. Considering the global expansion of dryland agriculture, the evidence of such socio-ecological cascading effects suggests the necessity to approach agricultural management at the landscape scale in desert regions.
Abstract The date palm (Phoenix dactylifera), an important agricultural crop in arid and semi-ari... more Abstract The date palm (Phoenix dactylifera), an important agricultural crop in arid and semi-arid areas around the Mediterranean Sea, has high nutritional, cultural, and economic values. Date palm cultivation in Israel is practiced in the arid and hyper-arid Jordan and Arava Valleys and is associated with high water and nitrogen (N) fertilization inputs, with rates of up to ~170 m3 water and ~6 kg N per full-grown tree annually, on average. While the palm’s water needs and budget have been intensively studied, the fate of applied N has received little attention to date. Understanding this fate is especially important since high fertilization rates of ~740 kg N ha−1 may have deleterious effects on the environment. Specifically, soil emissions of nitrous oxide (N2O) and leaching of nitrate (NO3-) are of major concern, due to their impact on climate change and groundwater contamination. We have measured the effect of four levels of N fertigation (fertilization + irrigation), between 0 and 2.55 kg N tree−1 yr−1, on N2O and NO3- fluxes during an annual growth season in a three-year-old date palm orchard located in Israel’s hyper-arid Arava Valley. We used static chambers for soil N2O flux estimations and measured drainage water NO3- concentrations at a 60-cm depth, together with a Cl- mass-balance-based water budget to estimate the NO3- leaching. We observed trivial soil N2O emissions of up to ~0.02% of applied N, while NO3- leaching was estimated to be as high as 36%. Dry areas between the trees, which did not receive any fertilization or irrigation, exhibited even lower N2O emissions than the irrigated areas. Inorganic N, however, accumulated during the dry months in the upper layer of the soil and was later lost at the onset of the winter rains. Our results provide the first-ever estimations of the potential environmental impact of date palm plantations in Israel and the Mediterranean Sea Basin.
There are gaps in our knowledge of the effects of irrigation water quality and amount on yield an... more There are gaps in our knowledge of the effects of irrigation water quality and amount on yield and postharvest quality of pepper fruit (Capsicum annuum L.). We studied the effects of water quality and quantity treatments on pepper fruits during subsequent simulated storage and shelf-life. Total yield decreased with increasing water salinity, but export-quality yield was not significantly different in fruits irrigated with water of either 1.6 or 2.8 dS/m, but there was a 30–35% reduction in export-quality yield following use of water at 4.5 dS/m. Water quantity hardly affected either total or export-quality yield. Water quality but not quantity significantly affected fruit weight loss after 14 days at 7 °C plus three days at 20 °C; irrigation with water at 2.8 dS/m gave the least weight loss. Fruits were significantly firmer after irrigation with good-quality water than with salty water. The saltier the water, the higher was the sugar content. Vitamin C content was not affected by wa...
Journal of Agricultural and Food Chemistry, Oct 1, 2009
The well-established health beneficial value of pomegranate juice is leading to increased demand ... more The well-established health beneficial value of pomegranate juice is leading to increased demand for pomegranate products and to the expansion of pomegranate orchards worldwide. The current study describes differences in the chemical composition of major ingredients of the arils and peels of 11 accessions grown in Mediterranean and desert climates in Israel. In most of the accessions, the levels of antioxidant activity and content of total phenolics, total anthocyanins, total soluble solids, glucose, fructose, and acidity were higher in the aril juice of fruit grown in the Mediterranean climate compared to those grown in the desert climate. However, the peels of fruit grown in the desert climate exhibited higher antioxidant activity, and the levels of total phenolics, including the two hydrolyzable tannins, punicalagin and punicalin, were higher compared to those in the peels of fruit grown in the Mediterranean climate. The results indicate that environmental conditions significantly affect pomegranate fruit quality and health beneficial compounds.
Three experiments were carried out using nine lysimeters filled with typical Southern Arava soil.... more Three experiments were carried out using nine lysimeters filled with typical Southern Arava soil. Each lysimeter was equipped with a scale for continuous weighing which established a highly accurate water and Ra mass balance. The experiments involved four crops; the irrigation scheme for each experiment and each lysimeter is shown in Table 1. 2 kg of plant tissues were oven-dried at 105 0 C for 24 h, and immediately pyrolized at 400 0 C. The samples were kept in a sealed standard container for three weeks to achieve secular equilibrium of the Ra and its decay products. Water samples were filtered through MnO 2 coated fibers. The fibers were then transferred into a sealed standard container and counted by gamma spectrometry. Soil samples excavated 15, 30, 45 and 60 cm underneath the stem were analyzed for profile distribution of Ra. Isotherms of Ra adsorption were constructed for the Arava soil. The soil was equilibrated with solutions containing 0, 1.7, 37.8, 1858, 4413, 5939 and 37763 Bq•l-1. 10-g soil triplicate samples with 20 ml of solution were mixed in 50-ml polypropylene centrifuge tubes and shaken for 24 h at 25 0 C. After equilibration, suspensions were centrifuged, filtered, and tested for pH and Ra. Measurements of the radium activity concentrations in soil, water and plant tissues samples were performed by standard gamma spectrometry methods. The kinetics of Ra distribution in soil and in drainage water was modeled by means of the HYDRUS 1-D software package (Simunek et al., 1998).
High radium concentrations may play a key role in the potential exploitation and utilization of g... more High radium concentrations may play a key role in the potential exploitation and utilization of groundwater for drinking water as well as for agricultural purposes. Radionuclides of natural origin, including radium, are present in all foodstuffs at varying degrees. In essence, the doses from natural radionuclides are not worthy to control since the concentrations are mostly low and the resources
The well-established health beneficial value of pomegranate juice is leading to increased demand ... more The well-established health beneficial value of pomegranate juice is leading to increased demand for pomegranate products and to the expansion of pomegranate orchards worldwide. The current study describes differences in the chemical composition of major ingredients of the arils and peels of 11 accessions grown in Mediterranean and desert climates in Israel. In most of the accessions, the levels of antioxidant activity and content of total phenolics, total anthocyanins, total soluble solids, glucose, fructose, and acidity were higher in the aril juice of fruit grown in the Mediterranean climate compared to those grown in the desert climate. However, the peels of fruit grown in the desert climate exhibited higher antioxidant activity, and the levels of total phenolics, including the two hydrolyzable tannins, punicalagin and punicalin, were higher compared to those in the peels of fruit grown in the Mediterranean climate. The results indicate that environmental conditions significantly affect pomegranate fruit quality and health beneficial compounds.
The Journal of Horticultural Science and Biotechnology
Off-types are quite common among tissue culture-produced date palm trees. The present study chara... more Off-types are quite common among tissue culture-produced date palm trees. The present study characterises a low fruit setting phenotype, found widely among tissue culture-produced date palms of the cultivar 'Barhee'. Most flowers in such trees turn into parthenocarpic fruitlets having three carpels. In severe cases, supernumerary carpels are formed. Other flower abnormalities include distortions of carpels and stigmas. The phenotype is alleviated in older trees, with about 50% of trees reverting to normal within 10 years from planting. Many flowers on the abnormal trees have impaired pollen tube elongation, with growth being limited to the stigma or to regions near its point of joining the carpel. Directional growth of pollen tubes ceases and tubes grow in different directions or stop growing completely. Possible mechanisms for this off-type phenotype, and its resemblance to other cases of somaclonal variation are discussed.
Irrigation is essential in arid regions to increase crop production. The combination of global ne... more Irrigation is essential in arid regions to increase crop production. The combination of global necessity to increase production of food and fiber with increasing water scarcity has led to utilization of water with high concentrations of salts for crop irrigation, particularly in arid and semi-arid regions.
International Journal of Postharvest Technology and Innovation, 2014
Irrigation water salinity effects on colour and health ingredients in the pomegranate peel were s... more Irrigation water salinity effects on colour and health ingredients in the pomegranate peel were studied in two accessions, 'Wonderful' and 'SP-2', grown under a wide range of salinities, 1.2 to 9 dS m -1 . Ripe fruit peels were analysed for phenolics and anthocyanins composition, and antioxidative capacity. Total phenolics concentration and antioxidative capacity were determined by the Folin-Ciocalteau and FRAP assays, respectively. Phenolics and anthocyanins composition was analysed by RP-HPLC. Increased salinity enhanced considerably the overall accumulation of phenolics and anthocyanins, and the antioxidative capacity in both cultivars; the magnitude of the effects was accession dependent. Mono-and di-glucosides of cyanidins, pelargonidins, and delphinidines were detected at proportions that varied with accession and salinity. Increased concentrations of gallotannins, flavonols and ellagic acid derivatives in 'Wonderful', and punicalagins, flavonols and ellagic acid derivatives in 'SP-2' accompanied elevated salinity levels. The results may benefit the pomegranate juice and byproduct valourisation industries, especially in the face of global water quality deterioration.
1] An accessible solution capable of reliably predicting plant-environmental interrelationships f... more 1] An accessible solution capable of reliably predicting plant-environmental interrelationships for variable species, climates, soils, and management options is a necessary tool for creating sustainable agriculture and environmental preservation. A mechanism-based analytical solution, the first of its kind that considers multiple environmental variables and their combined effects on plant response, was developed and tested. Water uptake by plants, water and salt leakage below the roots, and yield are calculated by solving for transpiration in a single mathematical expression according to limitations imposed by root zone salinity and water status. Input variables include the quantity and salinity of applied water, terms for plant sensitivity to salinity and to water stress, potential evapotranspiration, and soil hydraulic parameters. Where water was not limiting, regression of predicted versus measured data resulted in r 2 = 0.96 with slope of 0.937 and intercept of 0.033 (not different from 1 and 0 at 99% confidence), where irrigation varied and salinity was not limiting the r 2 = 0.94 with slope of 0.906 and intercept of 0.044 (not different from 1 and 0 at 99% confidence), where both salinity and water levels varied r 2 = 0.94 with slope of 0.966 and intercept of 0.033 (not different from 1 and 0 at 99% confidence). Application of the model for agricultural and environmental management and economic analysis is discussed. For example, a farmer in the Arava in Israel where irrigation water salinity is high (electrical conductivity of 3 dS m À1 ) cannot expect to reach greater than 70% of the potential yield for a pepper crop with any amount of irrigation. By choosing melon, the farmer can achieve 90% of potential yield with the same quality and quantity of water.
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Papers by Effi Tripler