Vassilis Aschonitis

Assessment of the Intrinsic Vulnerability of Agricultural Land to Water and Nitrogen Losses via Deterministic Approach and Regression Analysis

A set of indices was developed in order to classify the vulnerability of agricultural land to water and nitrogen losses (LOS), setting a basis for the integrated water resources management in agricultural systems. To calibrate the indices using multiple regression analysis, the simulation results of Groundwater Loading Effects of Agricultural Management Systems (GLEAMS) model for combinations of different soil properties, topography, and climatic conditions of a reference field crop were used as “observed values.” GLEAMS quantified (1) the annual losses of the percolated water beneath the root zone, (2) the annual losses of the surface runoff, (3) the annual losses of the nitrogen leaching beneath the root zone, and (4) the annual losses of nitrogen through the surface runoff, which were used to calibrate the following indices LOSW-P, LOSW-R, LOSN-PN, and LOSN-RN, respectively. All the simulations to gain the LOS indices were carried out for the same reference field crop, the same nitrogen fertilization, and the same irrigation practice, in order to obtain the intrinsic vulnerability of agricultural land to water and nitrogen losses. The LOS indices were also combined to derive nitrogen concentrations in the percolated and in the runoff water. Finally, the connection of LOS indices with the groundwater was performed using an additional equation, which determines the minimum transit time of the percolated water to reach the groundwater table.

Environmental stressor gradients hierarchically regulate macrozoobenthic community turnover in lotic systems of Northern Italy

AbstractEnvironmental stressors present a hierarchical influence on freshwater organisms. This study investigates the hierarchy of environmental stressor gradients, which regulate the composition of instream macroinvertebrate communities of northern Italy (Po Valley and the south-eastern Alps). Species and environmental data were derived from 585 monitoring sites. Environmental parameters were split into three groups, describing (i) ecoregional, (ii) hydromorphological, and (iii) water quality attributes. Partial Redundancy Analysis (partial RDA) was used to hierarchically rank the group effects, which were expressed as unique (group specific) and joint effects (of two groups together). Overall, ecoregion explained more variance (30.2%) than hydromorphology (24.8%) and water quality (22.3%). Unique effects were generally low, but ecoregional unique effects were twice as high as those of the other groups. The analysis of single environmental variables highlighted significant effects of anthropogenic impact related to the substrate size composition, riparian vegetation, flow conditions, and Escherichia coli (surrogate descriptor of organic fecal pollution). Such stressor hierarchies can support biodiversity conservation plans, while the high joint effects of stressor groups suggested the need for combined management activities, addressing the respective stressors and stressor groups in concert. Management measures addressing only one stressor group isolated from others are likely to be less effective, or even ineffective.

Estimation of Leaf Area Index and Foliage Area Index of Rice using an Indirect Gravimetric Method

The aim of this study was to present a gravimetric method for the estimation of leaf area index (LAI) and foliage area index (FAI) of rice. The method estimates indirectly the LAI-FAI variation during the growing season using simple measurements during harvest, based on a module of predetermined relations among agronomic parameters. The method confronts the limitations of other methods under specific conditions, such as (a) high plant densities and high LAI-FAI values, where indirect optical methods are restricted and (b) experiments related to crop modeling applications where direct destructive methods are not allowed because they alter the initial design of the experimental setup. The method was applied for the high-yield cultivar (Oryza sativa L. ssp. indica, cv. Thaibonnet) during 2-year evapotranspiration experiments in lysimeters. The method identified the differences between the replicate lysimeters, and LAI-FAI estimations were significantly correlated with the final grain yields and the crop factors obtained from evapotranspiration measurements.

Assessment of rural and highly seasonal tourist activity plus drought effects on reservoir operation in a semi-arid region of Greece using the WEAP model

The WEAP (Water Evaluation and Planning) model was used to estimate the effects of drought in addition to rural and tourist activity on the operation of two multi-purpose reservoirs in the Chalkidiki region of Greece. In scenarios based on historical data from 1975–2005, the fully effective months exceeded 85% of the total simulation period, while short-term droughts (less than two years’ duration) made the reservoirs ineffective to cover summer water demand. The results show that short-term droughts, in combination with high competition for water supply during summer between tourist and rural activities, may have environmental and social implications in semi-arid environments.

Run to the hills: exotic fish invasions and water quality degradation drive native fish to higher altitudes

While the significance of anthropogenic pressures in shaping species distributions and abundances is undeniable, some ambiguity still remains on their relative magnitude and interplay with natural environmental factors. In our study, we examined 91 late-invasion-stage river locations in Northern Italy using ordination methods and variance partitioning (partial-CCA), as well as an assessment of environmental thresholds (TITAN), to attempt to disentangle the effects of eutrophication and exotic species on native species. We found that exotic species, jointly with water quality (primarily eutrophication) and geomorphology, are the main drivers of the distribution of native species and that native species suffer more joint effects than exotic species. We also found that water temperature clearly separates species distributions and that some native species, like Italian bleak (Alburnus alborella) and Italian rudd (Scardinius hesperidicus), seem to be the most resilient to exotic fish species. We also analyzed the dataset for nestedness (BINMATNEST) to identify priority targets of conservation. As a result, we confirmed that altitude correlated negatively with eutrophication and nestedness of exotic species and positively with native species. Overall, our analysis was able to detect the effects of species invasions even at a late invasion stage, although reciprocal effects seemed comparable at this stage. Exotic species have pushed most native species on the edge of local extinction in several sites and displaced most of them on the rim of their natural distribution. Any potential site- and species-specific conservation action aimed at improving this situation could benefit from a carefully considered prioritization to yield the highest results-per-effort and success rate. However, we encourage future research to update the information available before singling out specific sites for conservation or outlining conservation actions.

Non-Market Ecosystem Services of Agricultural Land and Priorities Towards a More Sustainable Agriculture in Italy

Ecosystems provide a range of services, commonly called Ecosystem Services (ESs), which are of fundamental importance to human well-being, health, livelihoods, and survival. One of the largest and most productiveecosystems is agricultural land. Agro-Ecosystems provide a range of services directly linked to the market (e.g. food and raw materials production) but also many others of high ecological value, which have an indirect economical contribution in the GDP (non-market ESs). These non-market services are not usually taken into account in the development of agricultural management strategies while their contribution is reduced due to non-sustainable agricultural practices. The aim of the study is to assess the potential economic contribution of the non-market services at national, regional, and provincial level in Italy and to propose a simplified index-based method for setting priorities at different scales of administration units for the implementation of sustainable agricultural practices (SAPs). The results of the study showed that the potential non-market value of agro-ecosystem services (AESs) in Italy can reach ~46.2 billion USD

Terrain Segmentation of Greece Using the Spatial and Seasonal Variation of Reference Crop Evapotranspiration

2007. This estimate shows that non-market AESs can play an important role in the national GDP if SAPs are followed. Finally, a priority ranking scheme for the implementation of SAPs was proposed at regional and provincial level which can be a valuable decision support tool for promoting sustainable agriculture policies.

Onsite and online FT-NIR spectroscopy for the estimation of total nitrogen and moisture content in poultry manure

The study presents a combination of techniques for integrated analysis of reference crop evapotranspiration () in GIS environment. The analysis is performed for Greece and includes the use of (a) ASCE-standardized Penman-Monteith method for the estimation of 50-year mean monthly , (b) cross-correlation and principal components analysis for the analysis of the spatiotemporal variability of , (c) -means clustering for terrain segmentation to regions with similar temporal variability of , and (d) general linear models for the description of based on clusters attributes. Cross-correlation revealed a negative correlation of with both elevation and latitude and a week positive correlation with longitude. The correlation between and elevation was maximized during the warm season, while the correlation with latitude was maximized during winter. The first two principal components accounted for the 97.9% of total variance of mean monthly . -means segmented Greece to 11 regions/clusters. The categorical factor of cluster number together with the parameters of elevation, latitude, and longitude described satisfactorily the through general linear models verifying the robustness of the cluster analysis. This research effort can contribute to hydroclimatic studies and to environmental decision support in relation to water resources management in agriculture.

Assessment of specific vulnerability to nitrates using LOS indices in the Ferrara Province, Italy

The nitrogen and moisture of manure are highly variable parameters and depend on animal type, husbandry techniques, environmental conditions and storage time. The precision in manure dose estimation for crops fertilization depends on the total nitrogen and moisture content just before its incorporation in the field. The aim of the study is to develop a Fourier Transform Near Infrared (FT-NIR) spectroscopy method to determine the total Kjeldhal nitrogen (TKN%) and moisture (M%) of different types of poultry manure prior to land application. Samples covering a wide range of poultry types and different husbandry conditions were obtained from farms of North-Eastern Italy in order to develop the method. The method was calibrated (R2 = 0.94 for TKN%, R2 = 0.99 for M%) and validated (R2 = 0.82 for TKN%, R2 = 0.95 for M%) in the laboratory. An external validation was also performed in situ with independent samples, of similar origin to the previous data set, which were collected just before application in the field. Spectra acquisitions for these samples were carried out using the same instrumentation which was placed in a special vehicle for monitoring campaigns. The results showed satisfactory prediction accuracy (R2 = 0.82 for TKN%, R2 = 0.93 for M%). Finally, an additional analysis was performed to discriminate the different types of poultry effluents. The TKN and M measurements in the disposal areas indicated that current agronomic practices lead to more than double poultry manure oversupply. The proposed FT-NIR methodology aims to improve the current fertilization management and environmental protection by providing fast and precise estimations of poultry manure doses prior to land application.

Comparison of Different “S-index” Expressions to Evaluate the State of Physical Soil Properties

A set of indices (LOS), based on a deterministic approach and regression analysis were used to assess intrinsic and specific vulnerability to nitrates in Ferrara Province, in northern Italy. To calibrate the LOS indices, using multiple regression analysis, the simulation results of GLEAMS model for combinations of different soil properties, topography and climatic conditions of a reference fieldcrop were used as “observed values”. Results of model were introduced in a GIS environment to obtain the vulnerability maps. Maps of water and nitrogen losses under the root zone (LOSW-P and LOSN-PN respectively) were used to obtain the map of relative concentration of percolated water (RCPW). Data on individual crops were used to calculate specific crop evapotranspiration rates (ETc) from potential evapotranspiration (PE). ETc values replaced PE values in the indices, to obtain both specific vulnerability map for water and nitrogen losses under the root zone (LOSW-P mod; LOSN-PN mod) and for relative nitrogen concentration of percolated water (RCPW mod). The RCPW mod map shows that concentration of nitrogen losses under the root zone is under water drinking limit of 50 mg/L (WFD; 2006/118/EC) all over the territory with highest concentrations along small areas of the coastal zone, where sandy textured soil are present (coastal dunes) and lowest concentrations where ETc is higher.