Organic amendment, and especially the use of composts, is a well-accepted sustainable agricultural practice. Compost increases soil carbon and microbial biomass, changes enzymatic activity, and enriches soil carbon and nitrogen stocks.... more
Organic amendment, and especially the use of composts, is a well-accepted sustainable agricultural practice. Compost increases soil carbon and microbial biomass, changes enzymatic activity, and enriches soil carbon and nitrogen stocks. However, relatively little is known about the immediate and long-term temporal dynamics of agricultural soil microbial communities following repeated compost applications. Our study was conducted at two field sites: Newe Ya’ar (NY, Mediterranean climate) and Gilat (G, semi-arid climate), both managed organically over 4 years under either conventional fertilization (0, zero compost) or three levels of compost amendment (20, 40 and 60 m3/ha or 2, 4, 6 L/m2). Microbial community dynamics in the soils was examined by high-and low-time-resolution analyses. Annual community composition in compost-amended soils was significantly affected by compost amendment levels in G (first, second and third years) and in NY (third year). Repeated sampling at high resolution (9–10 times over 1 year) showed that at both sites, compost application initially induced a strong shift in microbial communities, lasting for up to 1 month, followed by a milder response. Compost application significantly elevated alpha diversity at both sites, but differed in the compost–dose correlation effect. We demonstrate higher abundance of taxa putatively involved in organic decomposition and characterized compost-related indicator taxa and a compost-derived core microbiome at both sites. Overall, this study describes temporal changes in the ecology of soil microbiomes in response to compost vs. conventional fertilization.HighlightsDose-dependent changes in soil microbiome structure by manure compost applicationDynamic short-and long-term changes in soil microbiomes by compost amendmentClimate, soil properties and management influence compost-amendment effectsImmediate and temporal cumulative effects of compost on soil α and β diversity
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Abstract The potential overestimation of soil microbial biolmass C, using the fumigation-extraction method, arising from the contribution of residual (i.e., non-evacuated) chloroform (CHCl3) to the fumigation flush of C, was recently... more
Abstract The potential overestimation of soil microbial biolmass C, using the fumigation-extraction method, arising from the contribution of residual (i.e., non-evacuated) chloroform (CHCl3) to the fumigation flush of C, was recently shown to be minor for agricultural topsoil samples. However, we hypothesized larger flush proportions of residual CHCl3–C, and hence greater biomass overestimations in low-biomass, subsoil samples due to the characteristically lower fumigation flushes of C in subsoils. The depth stratification (0–100 cm) of fumigation-extractable C and CHCl3–C was determined in six soil profiles (three loesses ranging from 6 to 20% clay and three vertisols ranging from 46 to 69% clay). Residual chloroform levels correlated positively with soil organic matter content but not with clay content and decreased down the profiles. Residual chloroform contributed ∼2.0% to biomass-C overestimation, independent of soil type or depth, thus refuting the study hypothesis and supporting the safe use of the fumigation-extraction method also with subsoil samples.
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Abstracts of Papers presented at a Workshop on Ecology of Botrytis and Sclerotinia and their Interaction With Other Microorganisms Abstracts of Papers Presented at a Workshop on Genetic Aspects ofFusarium oxysporum and Related Species Abstracts of Papers and Discussion Contributions Presented at ...more
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The use of biostimulants with plant growth-promoting properties, but without significant input of nutrients, is discussed as a strategy to increase stress resistance and nutrient use efficiency of crops. However, limited reproducibility... more
The use of biostimulants with plant growth-promoting properties, but without significant input of nutrients, is discussed as a strategy to increase stress resistance and nutrient use efficiency of crops. However, limited reproducibility under real production conditions remains a major challenge. The use of combination products based on microbial and non-microbial biostimulants or microbial consortia, with the aim to exploit complementary or synergistic interactions and increase the flexibility of responses under different environmental conditions, is discussed as a potential strategy to overcome this problem. This study aimed at comparing the efficiency of selected microbial single-strain inoculants with proven plant-growth promoting potential versus consortium products under real production conditions in large-scale tomato cultivation systems, exposed to different environmental challenges. In a protected greenhouse production system at Timisoara, Romania, with composted cow manure,...
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Water quality, soil, and climate can interact to limit photosynthesis and to increase photo-oxidative damage in sensitive plants. This research compared diffusive and non-diffusive limitations to photosynthesis as well as photorespiration... more
Water quality, soil, and climate can interact to limit photosynthesis and to increase photo-oxidative damage in sensitive plants. This research compared diffusive and non-diffusive limitations to photosynthesis as well as photorespiration of leaves of grapefruit trees in heavy clay and sandy soils having a previous history of treated wastewater irrigation for >10 years (TWW), with different water qualities (fresh water FW vs TWW and TWW+Na) in two arid climates (summer vs winter) and in orchard and lysimeter experiments. TWW irrigation increased salts (Na(+) and Cl(-) ), membrane leakage, proline and soluble sugar content, and decreased osmotic potentials in leaves of all experiments. Reduced leaf growth and higher stomatal and non-stomatal (i.e. mesophyll) limitations were found in summer and on clay soil for TWW and TWW+Na treatments in comparison to winter, sandy soil, and FW irrigation, respectively. Stomatal closure, lower chlorophyll content and altered Rubisco activity are...
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One of the main goals of modern agriculture is to achieve sustainability by maintaining crop productivity while avoiding soil degradation. Intensive cultivation could lead to a reduction in soil organic matter that could affect the... more
One of the main goals of modern agriculture is to achieve sustainability by maintaining crop productivity while avoiding soil degradation. Intensive cultivation could lead to a reduction in soil organic matter that could affect the structure stability and hydraulic conductivity of the soil. Moreover, crops extract nutrients from the soil that are taken away from the field when harvested, and as a consequence, the addition of fertilizers to the soil is necessary to maintain crop productivity. One way to deal with these problems is to incorporate crop residues into the soil after harvest. Crop residues are a source of organic matter that could improve soil physical properties, such as aggregate stability and soil hydraulic conductivity. However, this effect could vary according to other soil properties, such as clay content, clay mineralogy, and the presence of other cementing materials in the soil (mainly carbonates and aluminum and iron oxides). In the present work, the interaction ...
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Research Interests: Environmental Science, Irrigation, Water quality, Biological Sciences, Environmental Sciences, and 15 moreRiver water, Hydraulic conductivity, Irrigation Water, Sodium Adsorption Ratio, Soil Structure, Soil loss, Water Quality, Organic Matter, Electric Conductivity, Sodic Soil, GEODERMA, Infiltration rate, Surface Runoff, Saturated hydraulic conductivity, and Suspended solid
Declining yields from farmland in the Bet She'an Valley, Israel, irrigated with Jordan River water, raised concerns about resource management and long term sustainability. An experiment was conducted in a... more
Declining yields from farmland in the Bet She'an Valley, Israel, irrigated with Jordan River water, raised concerns about resource management and long term sustainability. An experiment was conducted in a commercial cotton field of the Bet She'an region, to assess the impact ...
Research Interests: Environmental Science, Irrigation, Agriculture, Israel, Middle East, and 15 moreBiological Sciences, Environmental Sciences, Drip Irrigation, Hydraulic conductivity, Pca, Irrigation Water, Multiple Regression, FDA, Indexation, Enzymatic Activity, Minimum Data Set, Electric Conductivity, GEODERMA, Linear Transformation, and Infiltration rate
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Effects of treated wastewater (TWW) and fresh water (FW) on autotrophic belowground respiration and respiratory coefficients (Q 10) in summer and winter were determined in a commercial citrus orchard. Efflux of CO 2 from soil and the... more
Effects of treated wastewater (TWW) and fresh water (FW) on autotrophic belowground respiration and respiratory coefficients (Q 10) in summer and winter were determined in a commercial citrus orchard. Efflux of CO 2 from soil and the often-ignored CO 2 transported in xylem sap were quantified; the latter derived from sap flux, CO 2 concentration ([CO 2 ]), pH, and temperature. Xylem [CO 2 ] scaled with xylem sap flux, pH and temperature. TWW and summer increased xylem sap pH (by 12% and 19%), soil CO 2 efflux (32% and 65%), and root respired CO 2 (10-15% and 55%) in comparison to FW and winter, respectively. About twice as much CO 2 from the below ground autotrophic portion of respiration moved in xylem sap as compared to that diffused from the roots into the soil, with seasonal variations of about ±10%. Maximum temperature-dependent respiratory coefficients (Q 10) were 4.7 for autotrophic root respiration and 3.8 for bulk soil CO 2 efflux, and values varied with water quality and season. Total below ground respiration exceeds that previously reported and is a large part of the tree's carbon balance. Increased respiratory losses caused by poor quality water may explain reduced orchard root growth and overall productivity.
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The objective of this research was to study the effects of N concentration and N-NO3: N-NH4 ratio in the nutrient solution on growth, transpiration, and nutrient uptake of greenhouse-grown pepper in a Mediterranean climate. The experiment... more
The objective of this research was to study the effects of N concentration and N-NO3: N-NH4 ratio in the nutrient solution on growth, transpiration, and nutrient uptake of greenhouse-grown pepper in a Mediterranean climate. The experiment included five total N levels (0.25 to 14 mmol·L-1, with a constant N-NO3: N-NH4 ratio of 4) and five treatments of different N-NO3: N-NH4 ratios (0.25 to 4, with a constant N concentration of 7 mmol·L-1). Plants were grown in an aero-hydroponic system in a climate-controlled greenhouse. The optimum N concentrations for maximum stem and leaf dry matter (DM) production were in the range of 8.0 to 9.2 mmol·L-1. The optimum N-NO3: N-NH4 ratio for maximal stem DM production was 3.5. The optimum value of N concentration for total fruit DM production was 9.4 mmol·L-1. Fruit DM production increased linearly with increasing N-NO3: N-NH4 ratio in the range studied. The N concentration, but not N source, affected leaf chlorophyll content. Shorter plants with ...
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Root restriction has been reported to reduce fruit yield, the incidence of blossom end rot (BER) and K concentration in tomato (Lycopersicon esculentum L. `F121') plant organs. The objectives of the present work were to study the... more
Root restriction has been reported to reduce fruit yield, the incidence of blossom end rot (BER) and K concentration in tomato (Lycopersicon esculentum L. `F121') plant organs. The objectives of the present work were to study the effect of root restriction, and combination of K and Ca solution concentrations, on greenhouse tomato fruit yield, quality and cation uptake. Root restriction reduced total yield but improved fruit quality by increasing the dry matter concentration and reducing the incidence of BER. Increasing the K concentration from 5.0 to 10 mmol·L-1 reduced the marketable yield, due to increased incidence of BER. Root restriction decreased K concentration and K/Ca ratio in tomato plant organs, but had no effect on K uptake rate per unit root fresh weight. Increasing K concentration from 2.5 to 10 mmol·L-1 increased the K concentration in plant organs and K uptake rate, but reduced that of Ca. In contrast, increasing Ca concentration in the solution had no effect on ...
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Résumé/Abstract The aim of the present research was to study changes in the major anti-oxidative enzyme activities known to be associated with the apoplast, during the induction of blossom-end rot (BER) in bell pepper (Capsicum annuum L.)... more
Résumé/Abstract The aim of the present research was to study changes in the major anti-oxidative enzyme activities known to be associated with the apoplast, during the induction of blossom-end rot (BER) in bell pepper (Capsicum annuum L.) fruits grown under saline conditions. Pepper plants of the BER-sensitive cv.'Mazurka'and less-sensitive cv.'Selica'were grown under control, low-and high-salinity irrigation regimes. Fruits were harvested continuously and, after approx. 7 months under these conditions, BER ...
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ABSTRACT
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Résumé/Abstract Blossom-end rot (BER) in pepper fruits is known as a" physiological" disease which is evoked by climatic and osmotic stresses (eg, high temperatures and salinity) and by deficit irrigation... more
Résumé/Abstract Blossom-end rot (BER) in pepper fruits is known as a" physiological" disease which is evoked by climatic and osmotic stresses (eg, high temperatures and salinity) and by deficit irrigation management. The physiological and biochemical mechanisms involved in the stimulation of BER are still a matter of dispute. It has been proposed that BER occurs under cultivation conditions that accelerate fruit growth beyond calcium supply to the growing tissue. In the present study, we investigated this hypothesis ...
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Research Interests: Plant Biology, Ecology, Tomato, Growth rate, Annals, and 3 moreRoot System, Root growth, and Soluble sugar
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ABSTRACT Appropriate geometries and depths of containers are essential in obtaining suitable available water and temperature in the root zone of containerized grown plants. The objectives of the present study were to examine the effect of... more
ABSTRACT Appropriate geometries and depths of containers are essential in obtaining suitable available water and temperature in the root zone of containerized grown plants. The objectives of the present study were to examine the effect of the geometry of a growth container with a given volume and irrigation frequency, on water content and temperature of the growing medium and on water uptake, yield and quality of lettuce (Lactuca sativa L.) as a model plant. Two experiments, in the spring and fall, were conducted in a greenhouse. Plants were grown in a volume of 4 L per plant of medium mixture of 0–8 mm tuff (90 %) with compost (10 %). Treatments included three container heights (10, 20 and 30 cm) and two irrigation frequencies (4–6 and 12–18 applications per day and 2 night applications for both). Lettuce head fresh weight was lower in the spring than in the fall and was not significantly affected by container geometry or irrigation frequency. However, the number of tip burn damaged leaves per plant increased significantly with container height, especially for the high irrigation frequency treatments. Container geometry had an effect on the water and temperature regimes. Water content values in tall and narrow containers were lower than those in short and wide containers that had an equal volume of growth medium per unit length. Higher medium temperatures and daily fluctuations were observed in the tall containers. The calculated evapotranspiration rate was higher in the tall containers, and a stronger effect on evapotranspiration was obtained with high irrigation frequency.
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ABSTRACT Root and microbial respiration is considered to be the main source of CO(2) production in soil; however, calcite dissolution in calcareous soils may contribute to the emitted CO(2). The major aim of this research was to quantify... more
ABSTRACT Root and microbial respiration is considered to be the main source of CO(2) production in soil; however, calcite dissolution in calcareous soils may contribute to the emitted CO(2). The major aim of this research was to quantify the contribution of CaCO(3) dissolution to CO(2) emission from a soil with and without the addition of an organic residue. Emissions of CO(2) and its delta(13)C from incubated noncalcareous (Golan Heights [GH], -26.23 parts per thousand) and calcareous (Bet She'an [BS], -11.47 parts per thousand) soils with and without the addition of a pasteurized chicken manure (PCM, -23.2 parts per thousand) were determined. During 56 d of incubation, 445 and 1804 mg kg(-1) CO(2)-C emitted from BS and GH soils, and PCM application caused additional emission of 2430 and 1884 mg kg(-1) CO(2)-C, respectively. The NO(3)(-)-N concentrations in the control BS and GH soils were 46 and 133 mg kg(-1) and PCM application increased it to 508 and 577 mg kg(-1), respectively. The emitted CO(2)-delta(13)C from BS and GH soils were -20.0 +/- 0.2 parts per thousand and -27.2 +/- 0.09 parts per thousand and application of PCM changed it to -20.6 +/- 0.42 parts per thousand and -23.7 +/- 0.16 parts per thousand, respectively. Consequently, the contributions of the inorganic source to CO(2)-C emission from BS without and with PCM and from GH with PCM were 113.4, 417.5, and 176 mg kg(-1) (26.5, 14.5, and 5% of the total), respectively. We suggest that oxidation of organic matter, mineralization of organic N, NH(4) nitrification, oxidation of organic S, and production of organic acids caused chemical dissolution of calcite and CO(2) emission. Ignoring this process will result in overestimation of the respired C.
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Research Interests: Microbiology, Carbon, Microbial Ecology, Ecology, Agriculture, and 15 moreIsrael, Global change, Seasonality, Fresh water, Semi Arid Region, Dissolved Organic Carbon, Microbial Activity, Organic carbon, Seasons, Organic Matter, Agricultural Irrigation, Hydrolysis, Organic Chemicals, Microbial community, and Diospyros
Research Interests: Earth Sciences, Soil, Agriculture, Biological Sciences, Phosphorus, and 15 moreEnvironmental Sciences, Sewage sludge, Raw materials, Nitrogen, Potassium, Nitrogen Uptake, Environmental quality, Fertilizers, First Year, Refuse disposal, Organic Waste, Crop Yield, Organic Matter, Environment Quality, and cattle manure
Environmentally sound management of the use of composts in agriculture relies on matching the rate of release of available N from compost-amended soils to the crop demand. To develop such management it is necessary to (i) characterize the... more
Environmentally sound management of the use of composts in agriculture relies on matching the rate of release of available N from compost-amended soils to the crop demand. To develop such management it is necessary to (i) characterize the properties of composts that control their rates of decomposition and release of N and (ii) determine the optimal amount of composts that should be applied annually to wheat (Triticum aestivum L.). Carbon and N mineralization were measured under controlled conditions to determine compost decomposition rate parameters, and the NCSOIL model was used to derive the organic wastes parameters that control the rates of N and C transformations in the soil. We also characterized the effect of a drying period to estimate the effects of the dry season on C and N dynamics in the soil. The optimized compost parameters were then used to predict mineral N concentration dynamics in a soil-wheat system after successive annual applications of compost. Sewage sludge compost (SSC) and cattle manure compost (CMC) mineralization characteristics showed similar partitioning into two components of differing ease of decomposition. The labile component accounted for 16 to 20% of total C and 11 to 14% of total N, and it decomposed at a rate of 2.4 x 10(-2) d(-1), whereas the resistant pool had a decomposition rate constant of 1.2 to 1.4 x 10(-4) d(-1). The main differences between the two composts resulted from their total C and N and inorganic N contents, which were determined analytically. The long-term effect of a drying period on C and N mineralization was negligible. Use of these optimization results in a simulation of compost mineralization under a wheat crop, with a modified plant-effect version of the NCSOIL model, enabled us to evaluate the effects of the following factors on the C and N dynamics in soil: (i) soil temperature, (ii) mineral N uptake by plants, and (iii) release of very labile organic C in root exudates. This labile organic C enhanced N immobilization following application, and so decreased the N available for uptake by plants.
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Nitrate contamination of groundwater under land used for intensive-agriculture is probably the most worrisome agro-hydrological sustainability problem worldwide. Vadose-zone samples from 0 to 9 m depth under citrus orchards overlying an... more
Nitrate contamination of groundwater under land used for intensive-agriculture is probably the most worrisome agro-hydrological sustainability problem worldwide. Vadose-zone samples from 0 to 9 m depth under citrus orchards overlying an unconfined aquifer were analyzed for variables controlling water flow and the fate and transport of nitrogen fertilizers. Steady-state estimates of water and NO3-N fluxes to groundwater were found to vary spatially in the ranges of 90-330 mm yr(-1) and 50-220 kg ha(-1) yr(-1), respectively. Calibration of transient models to two selected vadose-zone profiles required limiting the concentration of NO3-N in the solution that is taken up by the roots to 30 mg L(-1). Results of an independent lysimeter experiment showed a similar nitrogen-uptake regime. Simulations of past conditions revealed a significant correlation between NO3-N flux to groundwater and the previous year's precipitation. Simulations of different nitrogen-application rates showed that using half of the nitrogen fertilizer added to the irrigation water by farmers would reduce average NO3-N flux to groundwater by 70%, decrease root nitrogen uptake by 20% and reduce the average pore water NO3-N concentration in the deep vadose zone to below the Israeli drinking water standard; hence this rate of nitrogen application was found to be agro-hydrologically sustainable. Beyond the investigation of nitrate fluxes to groundwater under citrus orchards and the interesting case-study aspects, this work demonstrates a methodology that enables skillful decisions concerning joint sustainability of both the water resource and agricultural production in a common environmental setting.
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apsim-Nwheat is a wheat crop system simulation model within the apsim framework which consists of modules that incorporate aspects of soil water, nitrogen, residues, wheat (Triticum aestivum L.) crop development and growth, including... more
apsim-Nwheat is a wheat crop system simulation model within the apsim framework which consists of modules that incorporate aspects of soil water, nitrogen, residues, wheat (Triticum aestivum L.) crop development and growth, including grain protein content. ...