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Katerji N.,French National Institute for Agricultural Research | Mastrorilli M.,Italian Agricultural Research Council | Lahmer F.Z.,Mediterranean Agronomic Institute | Oweis T.,ICARDA
European Journal of Agronomy | Year: 2012

The current study aims to examine the hypothesis that the determination of the emergence rate is a possible indicator of the plant potential to tolerate soil salinity under field conditions. This hypothesis is analysed using specific experiments on salt-sensitive (chickpea and broad bean) and salt-tolerant (durum wheat and barley) species.For each of the four crops, two varieties that displayed a clear difference in yield production under a saline environment were subjected to two types of analysis. The first type of analysis was used to classify the salt-tolerance of different varieties using two criteria as follows: (1) the relationship between yield and soil salinity; (2) the water use efficiency. The second type of analysis determined the emergence rate as a function of the irrigation-water salinity.The criteria that were used in the current study for classifying the varietal salt-tolerance of each crop provided similar conclusions. However, the hypothesis that the emergence rate was associated with the varietal potential for salt-tolerance was not confirmed by the results of this analysis. On the contrary, the results demonstrated that some varieties combined poor emergence with a high crop salt-tolerance. These varieties included ILC 3279 of the chickpea and Cham-1 of the durum wheat.The current study does not support the hypothesis that postulated the existence of a correlation between the emergence rate and the potential of a variety to tolerate the soil salinity. Finally, practical applications of these conclusions are discussed. © 2011 Elsevier B.V.

Katerji N.,French National Institute for Agricultural Research | Mastrorilli M.,Italian Agricultural Research Council | Lahmer F.Z.,Mediterranean Agronomic Institute | Maalouf F.,ICARDA | Oweis T.,ICARDA
European Journal of Agronomy | Year: 2011

The response of faba bean (Vicia faba L., variety ILB1814) was evaluated in a factorial salinity-drought experiment, combining three levels of salinity in the irrigation water (EC 1.0, 2.3 and 3.6. dS/m) and two levels of plant water status during two successive cropping seasons. The two levels of plant water status were obtained by supplying irrigation when the pre-dawn leaf water potential of the control treatments attained values of -0.3 and -0.6. MPa. The experiment was designed to analyse the effects of soil salinity, the effects of drought (detected by the level of the plant water status), and the combined effect of salinity and drought on the plant-water relationships, nitrogen balance and crop productivity (for both grain and straw). Soil salinity levels equal to or higher than 6.5dSm-1 affected the plants by reducing the grain number but not the straw weight. Drought at flowering, early podding and grain-filling stages reduced both grain and straw yields. Moreover, yield reductions were associated with increasing soil salinity levels, confirming an interaction between the salinity and drought effects on faba bean productivity. Symbiotic nitrogen fixation, as evaluated by the nitrogen balance, was more affected by drought than by salinity, and it may explain the absence of any observed effects of salinity under drought conditions.The comparison of these results with those obtained in similar experiments on wheat and barley revealed that these cereals and faba bean have contrasting behaviours under saline-drought conditions. © 2011 Elsevier B.V.

Katerji N.,French National Institute for Agricultural Research | Mastrorilli M.,Italian Agricultural Research Council | Lahmar F.,Mediterranean Agronomic Institute
Agricultural Water Management | Year: 2011

This study aims at validating the methodology proposed by Allen et al. (1998) to calculate the stress coefficient Ks (ratio between actual and maximal evapotranspiration) under saline environment conditions not affected by soil water shortage. Validation was performed in Mediterranean region (Bari, southern Italy) on two crops: a winter crop (broad bean) and a spring crop (potato) grown in lysimeters, on clay and loam soils, having different levels of salinity. Preliminary observations were carried out to verify that the conditions established by Allen et al. (1998) for applying this Ks calculation methodology were fulfilled.The measured Ks values showed an evolution during the growing cycle. Ks values were close to 1 after emergence, and decreased at the end of the growing cycle. Contrarily, the calculated Ks values showed steady values during the whole crop cycle, being lower than the measured Ks. Only at the end of the crop cycle the calculated Ks values approached those measured. The various causes of differences between measured and calculated values of Ks are analyzed in this study.The observed differences between calculated and measured values of Ks led to an underestimation of calculated actual evapotranspiration (AET), at different stages in the crop growing cycle, by an average of 12%. The analysis of seasonal evapotranspiration as a function of soil salinity allows for a modulation of this mean value. The underestimation was quite negligible (close to 4%), if the average value of ECe during the crop cycle was close or lower than 3dSm-1. On the contrary, the underestimation in evapotranspiration was close to 20% when the ECe raised up to 6dSm-1.An underestimation of calculated AET in saline environment conditions, by the methodology proposed by Allen et al. (1998), causes the appearance of an additional water stress, mainly when soil salinity, increases due to the combined effect of soil water shortage and water quality. Different solutions are proposed to improve the calculation of AET in this condition. © 2010 Elsevier B.V.

Naspetti S.,Marche Polytechnic University | Naspetti S.,Mediterranean Agronomic Institute | Pugliese P.,Mediterranean Agronomic Institute | Salame N.,United Nation
New Medit | Year: 2016

In Lebanon, the agricultural sector suffers from both internal and external problems that opposed its development. Relatively high production costs, unregulated use of chemicals and the absence of extension services can be considered the most important in addition to groundwater pollution, high-level migration towards cities, lack of economic policy for internal and external market, and finally the inability of the government to finance the sector. In this context, organic farming might be considered as a possible alternative to the current crisis of the sector, and could be a solution to many of the abovementioned problems. In an attempt to thoroughly understand why Lebanese farmers do not apply the organic methods of production, this paper illustrates the results of a study on farmers' motivations for adopting either the organic or the conventional farming practices. In order to carry out the research, the means-end approach (Reynolds and Gutman, 1988) has been applied. The analysis methodology traditionally used for consumer analysis has been modified and adapted to investigate the cognitive structures (objective networks) of 35 Lebanese farmers. The results help understand the reasons determining the choice of the type of agriculture to adopt and underlie the diversity of the motivations between organic and conventional farmers.

Coppola A.,University of Basilicata | Comegna A.,University of Basilicata | Dragonetti G.,University of Basilicata | Dragonetti G.,University of Alberta | And 5 more authors.
Advances in Water Resources | Year: 2011

Solute transport parameters are known to be scale-dependent due mainly to the increasing scale of heterogeneities with transport distance and with the lateral extent of the transport field examined. Based on a transect solute transport experiment, in this paper we studied this scale dependence by distinguishing three different scales with different homogeneity degrees of the porous medium: the observation scale, transport scale and transect scale. The main objective was to extend the approach proposed by van Wesenbeeck and Kachanoski to evaluating the role of textural heterogeneities on the transition from the observation scale to the transport scale. The approach is based on the scale dependence of transport moments estimated from solute concentrations distributions. In our study, these moments were calculated starting from time normalized resident concentrations measured by time domain reflectometry (TDR) probes at three depths in 37 soil sites 1 m apart along a transect during a steady state transport experiment. The Generalized Transfer Function (GTF) was used to describe the evolution of apparent solute spreading along the soil profile at each observation site by analyzing the propagation of the moments of the concentration distributions. Spectral analysis was used to quantify the relationship between the solid phase heterogeneities (namely, texture and stones) and the scale dependence of the solute transport parameters. Coupling the two approaches allowed us to identify two different transport scales (around 4-5 m and 20 m, respectively) mainly induced by the spatial pattern of soil textural properties. The analysis showed that the larger transport scale is mainly determined by the skeleton pattern of variability. Our analysis showed that the organization in hierarchical levels of soil variability may have major effects on the differences between solute transport behavior at transport scale and transect scale, as the transect scale parameters will include information from different scales of heterogeneities. © 2011 Elsevier Ltd.

Comegna A.,University of Basilicata | Coppola A.,University of Basilicata | Dragonetti G.,Mediterranean Agronomic Institute | Sommella A.,University of Naples Federico II
Vadose Zone Journal | Year: 2016

In recent years, several studies have been conducted in the detection and observation of nonaqueous-phase liquids (NAPLs) in contaminated soils. Successful remediation of an NAPL-contaminated site requires appropriate characterization of both the plume extent and the soil volumetric NAPL content (θNAPL). Noninvasive geophysical techniques, such as time domain reflectometry (TDR), may be used to discriminate between θNAPL and soil volumetric water content (θw). Accordingly, the main aim of this work was to develop a TDR waveform interpretation method based on soil dielectric permittivity measurement and observation of the change in the reflected TDR signal amplitude at relatively long times from the waveform source. We demonstrated that the asymptotic value of the reflection signal coefficient can be univocally related with θNAPL in an unsaturated soil. In the procedure adopted, a new formulation of a dielectric mixing model was also derived, introducing a fourth phase that takes the NAPL presence into account. Multiple samples of sandy, silt loam, and loamy soils, at predetermined different θw and θNAPL, were tested, each test consisting in emitting a TDR signal to the soil sample and receiving and analyzing the reflected electromagnetic wave. An empirical dielectric mixing model was calibrated and implemented to estimate the θNAPL. Equipment calibration, measurement accuracy, and error sources, related both to the experimental procedure setup and to the sample preparation conditions, are discussed. The results show that the suggested methodology can be used to obtain predictions of volumetric NAPL content (θNAPL) with acceptable accuracy (R2 = 0.95). © Soil Science Society of America 5585 Guilford Rd., Madison, WI 53711 USA. All rights reserved.

Coppola A.,University of Basilicata | Comegna A.,University of Basilicata | Dragonetti G.,University of Basilicata | Lamaddalena N.,Mediterranean Agronomic Institute | And 2 more authors.
Soil and Tillage Research | Year: 2011

Surface water content data measured by TDR in the tilled zone of an experimental field were analyzed by spatial and temporal statistical techniques. First, spatial autocorrelation was explored by using isotropic variograms. The temporal persistence of the spatial pattern was verified by calculating Pearson's correlation coefficients. Second, a temporal analysis technique was tested, aiming to identify sites with time-invariant statistical properties of the probability density function. These locations would provide water content measurements consistent with the mean or given percentile values for the whole field. The results showed two different behaviors of the surface water content, the first for a drier stage with no or little rainfall, the second arising after more significant rainfall. In neither stage was a significant spatial dependence found. However, in the drier stage, the experimental semivariance calculated for each spatial lag was lower than in the wetter stage. Also, a reverse pattern of the water content was observed in the two stages, with drier zones becoming wetter and vice versa. For each stage, a significant temporal stability of the water content pattern was proved, which was confirmed by calculating Pearson's correlation coefficients. The percentile at each measurement location varied over time, with more significant changes between the drier and wetter stages. Nevertheless, for a few sites the percentile was quite stable during both the dry and wet stages. Site 34 was steadily in the range 0.4-0.6 and was identified as being representative of the average water content in the investigated field for both dry and wet seasons. This was confirmed by calculating Spearman's rank coefficients. © 2011 Elsevier B.V.

Coppola A.,University of Basilicata | Dragonetti G.,University of Basilicata | Comegna A.,University of Basilicata | Lamaddalena N.,Mediterranean Agronomic Institute | And 3 more authors.
Soil and Tillage Research | Year: 2013

Addressing the impact of soil heterogeneities on soil water patterns at the field scale involves measuring and/or modeling water content evolution with fine spatial and temporal resolution. The presence of stones introduces difficulties for both the measurement of the water content by TDR probes and the soil hydraulic properties. In this study, the role of stones was explicitly considered for interpreting TDR-based measurements of water content and its variability in the field, as well as for adjusting the hydraulic properties of the fine fraction to that of the bulk soil including stones. The in situ TDR measurements of the bulk dielectric constant were converted to the bulk water content by adopting an approach explicitly accounting for the contribution of the volumetric fraction of stones and their dielectric properties. The water content evolution was also simulated by using laboratory-based hydraulic properties as input in a numerical model. The soil hydraulic properties of the bulk soil (stones plus fine soil) were deduced from the soil core-based hydraulic properties according to the volumetric proportion of stones in the bulk soil. For the hydraulic conductivity, we assumed that the effect of stones is simply to reduce the cross-sectional area of the bulk sample available for flow, by assuming that, on the average, the areal fraction of stones is equal to the volume fraction of stones. In modeling soil water content, we also analyzed the effect of reducing hydraulic conductivity and water retention on the evaporation process and thus on the areal distribution of soil water content. Finally, the effect of stoniness was considered as a possible explanation of the differences frequently observed between the measured hydraulic behavior and that estimated by using PTFs. Overall, both the measured and PTF-based hydraulic properties, when scaled for stoniness, proved to be adequate for describing the average evolution of the water content. However, measured hydraulic properties describe the areal distribution of water contents in the field better than PTF. © 2012 Elsevier B.V.

News Article | December 20, 2015
Site: phys.org

Prosecutors in Puglia banned the culling of trees apparently affected with Xylella Fastidiosa, a bacteria with no known cure, accusing a task-force of university experts led by a governor-appointed commissioner of harming the environment. The stop comes despite pressure from the European Union to fell the trees, with prosecutors arguing that "Europe was given a false interpretation of the Xylella situation... by regional institutions using inaccurate facts". There was no proof of a clear link between the bacteria and symptoms of desiccation affecting thousands of trees in southern Italy, the prosecutors said, insisting further research was needed to prevent trees being wrongly axed. "We have found trees not affected by desiccation which tested positive for Xylella and dried out trees which tested negative," Lecce prosecutor Cataldo Motta told journalists at a press conference. He also said uprooting affected groves had not only failed to reduce the dry wood symptom, but that it was actually on the rise. The ten accused, mostly teachers and researchers, are being investigated, among other things, for "spreading a plant disease" and "destruction or disfigurement of natural beauty" in the area surrounding Lecce from 2010 to today. "From the moment the pathology of the desiccation of the olive trees appeared, without the cause being identified, a series of experiments were conducted using highly invasive products, prohibited by law, seriously compromising the environment, without any prior study of the impact," the prosecutors said in their written accusation. The probe will look into the possible dangers to public health caused by the use of the pesticides and allegations of a conflict of interest over the products used. Those accused include government-appointed project supervisor Giuseppe Silletti, staff at Italy's Plant Health Observatory, teachers at the University of Bari and researchers at the Mediterranean Agronomic Institute. Silletti told journalists he had been acting "in defence of the countryside". Puglia governor Michele Emiliano welcomed the investigation, as providing a basis to "challenge the European Union's strategy against Xylella, which is based essentially on the mass eradication of diseased and healthy trees". The disease, which is not harmful to humans but can kill over 200 species of plants and poses a serious threat to Italy's olive and orange groves and vineyards, was first spotted in 2013 but the country was divided over how to tackle the threat. Concerned over a potential spread of the bacteria to France or Spain, the EU urged Rome to destroy affected specimens—a move that would potentially affect 10 percent of Puglia's 11 million or so olive trees, some of which are over a century old. In October, Silletti finally ordered some 3,000 trees to be razed under an emergency decree. But only 1,600 trees have been destroyed so far, with outraged olive farmers filing a flurry of appeals in Italian courts claiming that the order—and a plantation ban—have no scientific basis and could decimate the industry.

Mohamad R.S.,Mediterranean Agronomic Institute | Bteich M.R.,Mediterranean Agronomic Institute | Cardone G.,Mediterranean Agronomic Institute | Marchini A.,University of Perugia
New Medit | Year: 2013

The regional law on the protection and enhancement of monumental olive trees landscape in Apulia represents a key action for the safeguarding of the area imprint and of its agricultural production. In this paper, a case study approach is used to evaluate the profitability of five organic farms in the Rural Parkland of Ancient Olive Trees. A microeconomic analysis is developed to assess the economic sustainability of ancient olive orchards in relation to other local existing types of olive orchards. Results show that ancient olive orchards have a positive net margin, although lower than the thickened and intensive ones. However, a better management and an optimization of agricultural practices of ancient trees can increase extra virgin olive oil production, reduce production costs, and decrease the net margin gap in the ancient orchards compared to the other ones. Governmental subsidies can help improving mechanization and promoting the denomination of "Extra virgin oil from Apulia ancient olive trees" foreseen by the Law.

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