ΥΔΑΤΙΚΟ ΑΠΟΤΥΠΩΜΑ ΤΩΝ ΚΑΛΛΙΕΡΓΕΙΩΝ ΤΗΣ ΠΕΔΙΑΔΑΣ ΤΟΥ ΝΕΣΤΟΥ ΣΥΜΦΩΝΑ ΜΕ ΤΗ ΜΕΘΟΔΟΛΟΓΙΑ ΤΗΣ ΕΚΤΙΜΗΣΗΣ ΚΥΚΛΟΥ ΖΩΗΣ

Η αλόγιστη χρήση των υδατικών αποθεμάτων μιας περιοχής για την άρδευση καλλιεργειών μπορεί να οδηγήσει σε εξάντληση των πόρων της περιοχής και συνεπώς σε αναποτελεσματική άρδευση. Επίσης, η εφαρμογή της καλλιέργειας μπορεί να οδηγήσει και σε υποβάθμιση των υδατικών πόρων, λόγω μεταφοράς συστατικών των λιπασμάτων στα υδατικά σώματα. Η αλληλεξάρτηση αυτή καλλιέργειας και οικοσυστήματος καλλιεργούμενης περιοχής, μπορεί να αποτυπωθεί και ποσοτικοποιηθεί μέσω του Υδατικού Αποτυπώματος της καλλιέργειας, σύμφωνα με τις αρχές της Εκτίμησης Κύκλου Ζωής. Στην παρούσα εργασία προσδιορίζεται το Υδατικό Αποτύπωμα των καλλιεργειών της πεδιάδας του ποταμού Νέστου. Τα αποτελέσματα της μελέτης στοχεύουν στην αποτελεσματική άρδευση της περιοχής, μέσω της ολοκληρωμένης και βιώσιμης διαχείρισης των υδατικών της πόρων

Optimal reservoir operation for irrigation purposes

The research performed in the framework of the completion of the Ph.D. dissertation, is focused on the optimal reservoir operation for irrigation purposes during the irrigation period. The time interval is the 10 days. The remainder period of year determines the reservoir storage in the beginning of the irrigation period, while so much the reservoir storage in the beginning of the irrigation period and inflow during the irrigation period are regulated and used for the irrigation. The objective function maximizes the total farm income, which is based on actual yield, area, production cost and crop prices. The constraints include the state equation of reservoir, reservoir storage, irrigation requirements of a crop and reservoir release, yield and cropped area. The decision variables are the optimal allocation of cultivation areas for any number of irrigated crops and the optimal irrigation schedule, which specifies the amount of irrigation to be applied to each crop during its growing season. The actual yield is calculated with the production function given by Jensen and the maximum evapotranspiration coincides with crop evapotranspiration, which is the product of a crop factor and the reference evapotranspiration which is computed from the FAO Penman-Monteith equation. The determination of the actual evapotranspiration is becomes with the soil water balance and soil water depletion function. The optimization of the nonlinear discrete-time dynamic model is performed in two stages. During the first stage the simulated annealing (SA) global optimization stochastic search algorithm is used and in a second stage it is refined the solution reached by the SA, using a stochastic gradient descent algorithm. SA has been proved under suitable conditions (Gauss distribution to generate test points, Boltzman distribution for acceptance of these and logarithmic reduction of temperature) to converge with probability one to the global optimal solution, in the limiting case of infinite iterations. The optimisation model is applied on historical and synthetically data from a planned reservoir on the Havrias River in Northern Greece. Synthetically data are referred to rainfall, inflow and reference evapotranspiration are calculated with frequency analysis Summary 321 in a synthetic series duration of 50 years (economic life of work), which resulted from 100 synthetic series that were produced for every of this variables. The optimization computes the optimal distribution of areas and crops, the water release to satisfy irrigation requirements and the total profit. The procedure is relatively easy to apply and can be used as a decision support tool for cropping patterns of an irrigated area and irrigation scheduling

Ecosystem Services Evaluation from Sustainable Water Management in Agriculture: An Example from An Intensely Irrigated Area in Central Greece

This study presents the provisional, regulating and cultural ecosystem services that can be delivered by the newly constructed multi-purpose reservoir of Lake Karla located in a water-scarce agricultural area in central Greece. The present short paper takes advantage of literature data and outputs produced from a dynamic GIS hydrologic and management model of the study area with SWAT that simulated hydrology, reservoir operation, irrigation practices and crop production. The paper highlights the net provisional services that the local agricultural society can gain from the full operation of Karla and the additional benefits arising, such as flood control, biodiversity maintenance, aesthetic improvement and touristic opportunities

Model Application for Estimation of Agri-Environmental Indicators of Kiwi Production: A Case Study in Northern Greece

Due to the sensitivity of kiwifruit to soil water and nutrient availability, kiwi production is often associated with over-watering and over-fertilization, especially with nitrogen (N), resulting in increased environmental risks. Crop models are powerful tools for simulating crop production and environmental impact of given management practices. In this study, the CropSyst model was applied to estimate soil N budget and environmental effects of kiwi production, with particular regard to N losses, in two grower-managed kiwi orchards in northern Greece, involving two seasons and different management practices. Management options included N fertilization and irrigation. Model estimates were compared with yield and soil mineral N content (0–90 cm depths) measured three times within the growing season. Agri-environmental indicators were calculated based on the N budget simulation results to assess the environmental consequences (focusing on N losses and water use efficiency) of the different management practices in kiwi production. According to model simulation results, kiwifruit yield and N uptake were similar in both orchards. N losses to the environment, however, were estimated on average to be 10.3% higher in the orchard with the higher inputs of irrigation water and N fertilizer. The orchard with the lower inputs showed better water and N use efficiency. N leaching losses were estimated to be higher than 70% of total available soil N in both study sites, indicating potential impact on groundwater quality. These findings demonstrate the necessity for improved irrigation and N fertilization management in kiwi production in the area

The Use of Appropriate Cultivar of Basil (Ocimum basilicum) Can Increase Water Use Efficiency under Water Stress

Drought is one of the major yield constraints of crop productivity for many crops. In addition, nowadays, climate change creates new challenges for crop adaptation in stressful environments. The objective of the present study was to determine the effect of water stress on five cultivars of basil (Mrs Burns, Cinnamon, Sweet, Red Rubin, Thai) and whether water use efficiency (WUE) can be increased by using the appropriate cultivar. Water stress affected the fresh and dry weight and also the partitioning of dry matter to leaves, flowers, and stems. Also, there are cultivars, such as Mrs Burns and Sweet, which were not affected by the limited amount of water and continued to produce a high amount of dry matter and also showed high essential oil yield. Essential oil content was not affected by the irrigation; however, essential oil yield was affected by the irrigation, and the highest values were found at Mrs Burns. The water use efficiency was affected by the cultivar and irrigation level, and the highest was found at Mrs Burns. The results show that using appropriate cultivars basil can achieve higher WUE and allow saving water resources and utilizing fields in areas with limited water resources for irrigation

Partial Replacement of Mineral-N Fertilizer Using Compost and Biochar to Improve Growth and Yield of Peanut (Arachishypogaea L.) Grown on a Sandy Loam Soil

In the 2017 and 2018 summer seasons, two field experiments were conducted at Ismailia Governorate, Egypt, to evaluate the effect of adding organic amendments combined with 50% of the recommended 100 kg ha-1 of mineral-N fertilization Ammonium nitrate (330 g N kg-1 ). The five organic sources were three types of biochar and two types of compost at a rate of 24 Mg ha-1 on peanuts (Arachis hypogaea L. Giza 6) grown on a sandy soil. Available N, P, K, Fe, Mn, and Zn concentrations in the soil after harvest increased due to the additional treatments, and the highest concentrations were due to Compost B (town refuse residues)+50 kg N ha-1 . Electrical Conductivity (EC) and soil pH decreased due to compost addition but slightly increased owing to biochar addition. The highest chlorophyll, protein, and oil contents of 42.8 mg g-1 , 226 g kg-1 , and 448 g kg-1 , respectively, were obtained due to addition of 50 Kg N ha-1 AN + Compost B. Generally, the addition of N fertilization 50 kg N ha-1 combined with compost had a favorable effect in improving soil properties and increasing peanut, oil, protein content and nutrient uptake as compared to other treatments

Assessment of Minimum Water Level in Lakes and Reservoirs Based on Their Morphological and Hydrological Features

The sustainable management of lakes and reservoirs requires the determination of their minimum environmental water level. Even though the assessment of minimum water level depends on a number of biotic and abiotic factors of the lake ecosystem, in many cases these factors are not entirely known and, furthermore, their evaluation is usually a challenging and laborious task. On the other hand, the lakes/reservoirs may comprise an important water resource to meet the requirements arising from economic activities. In this paper, the morphological and hydrological features of four lakes of northern Greece were analysed in order to assess their minimum environmental water level. The hydromorphological analysis was based on the relationship of the lake surface area and volume with water level as well as the water inflow from the lake’s hydrological catchment area, considering as the lake’s critical volume storage, the annual water volume flowing into a lake from its hydrological catchment area with a probability of exceedance 50% of a long time series of hydrological years. By combining morphological and hydrological features, the proposed methodology aimed to extend the analysis based solely on morphological features, and assess more comprehensively the minimum environmental water level in the four lakes, ensuring also the rising from the minimum level to the maximum (overflow) level for most of the hydrological years

A GIS-Based Comparative Groundwater Vulnerability Assessment Using Modified-DRASTIC, Modified-SINTACS and NV Index in a Porous Aquifer, Greece

Groundwater vulnerability assessment is of pivotal importance for the sustainable management of groundwater resources, particularly in regions with intense agricultural activity. This research primarily aims to assess and delineate groundwater vulnerability zones using a comparative approach of three different GIS-based modified models, namely Pesticide DRASTIC-LU, Nitrate SINTACS-LU and Nitrate NV index. For this reason, eight hydrogeological parameters were employed to analyze the spatial distribution of groundwater vulnerability in the Nea Moudania aquifer, Chalkidiki, Greece. This multi-model methodology was implemented to ascertain the most reliable method for the study area. Results indicated that the southern and southwestern parts of the study area exhibited the highest vulnerability potential, whilst the northern part displayed the lowest. Moreover, single-parameter sensitivity analysis has revealed that land use and topography were the most critical parameters of the vulnerability indexes, whereas hydraulic conductivity was the least influential. Finally, the three vulnerability models were validated with nitrate concentrations of groundwater samples. Results revealed that the Nitrate NV index was the most accurate method, trailed by the Pesticide DRASTIC-LU and the Nitrate SINTACS-LU

Screening Life Cycle Environmental Impacts and Assessing Economic Performance of Floating Wetlands for Marine Water Pollution Control

The growing environmental awareness of society, the advancement of nature-based solutions (NbSs), and the need for reliable and cost-effective solutions create a favorable environment of opportunities for floating wetlands as alternative solutions for marine water pollution control. The aim of this work was to screen, through OpenLCA, the environmental impacts of floating wetlands for marine water pollution control at various life cycle stages of the system, and assess its economic performance and contribution to the welfare of society. The stage of raw materials production and acquisition was found to be responsible for the main environmental impacts of the floating wetlands, especially on global warming potential, whereas the main impact of the operational stage was related to the eutrophication potential due to N and P residuals in the effluent. The economic performance indicators of economic net present value (ENPV), economic rate of return (ERR), and benefits/costs ratio (B/C ratio) indicate, although marginally, that floating wetlands may constitute a viable investment with potential positive socioeconomic impacts. However, there are still several scientific challenges and technical issues to be considered for the operational application of such systems at full-scale in marine environments