Panagiotis Tziachris

• Msc, PhD
• Spatial Data Management at National Agricultural Research Foundation

Pan evaporation (Epan) of class A pan evaporimeter under local semi-arid conditions was modelled in this study based on meteorological observations as input data using an integrated regression approach that includes three steps: a) first step: appropriate selection of transformations for reducing normality departures of independent variables and ri...

Storm ‘Daniel’ caused the most severe flood phenomenon that Greece has ever experienced, with thousands of hectares of farmland submerged for days. This led to sediment deposition in the inundated areas, which significantly altered the chemical properties of the soil, as revealed by extensive soil sampling and laboratory analysis. The causal relati...

The storm 'Daniel' has caused the most severe flood phenomenon that Greece has ever experienced, with thousands of hectares of farmland submerged for days. This led to sediment deposition in the inundated areas, which significantly altered the chemical properties of the soil, as revealed by extensive soil sampling and laboratory analysis. Causal re...

Machine learning (ML) algorithms are extensively used with outstanding prediction accuracy. However, in some cases, their overfitting capabilities, along with inadvertent biases, might produce overly optimistic results. Spatial data are a special kind of data that could introduce biases to ML due to their intrinsic spatial autocorrelation. To addre...

In this dataset we present soil data analyses with properties such as pH, organic matter (OM), salinity (EC), etc., major elements (N, P, K, Mg) as well as some microelements (Fe, Zn, Mn, Cu, B) with significant impact on plant nutrition. The samples were collected from the top 30 cm of the soil depth through a period of 5 successive years. The sur...

One of the core tasks in digital soil mapping (DSM) studies is the estimation of the spatial distribution of different soil variables. In addition, however, assessing the uncertainty of these estimations is equally important, something that a lot of current DSM studies lack. Machine learning (ML) methods are increasingly used in this scientific fie...

A classic method for assessing the reference crop evapotranspiration (ETo) is the pan evaporation (Epan) method that uses Epan measurements and pan coefficient (kp) models, which can be functions of relative humidity (RH), wind speed (u2), and temperature (T). The aim of this study is to present a methodology for evaluating the robustness of regres...

How fully productive olive trees (Olea europaea L., cv. 'Chondrolia Chalkidikis') manage to over-satisfy their P nutritional needs under low Olsen P availability in soils? A B S T R A C T Often, from soil and plant tissue analyses, over-sufficient foliar P levels in olive trees, grown under low Olsen P availability, are determined. In order to deep...

In the current paper we assess different machine learning (ML) models and hybrid geostatistical methods in the prediction of soil pH using digital elevation model derivates (environmental covariates) and co-located soil parameters (soil covariates). The study was located in the area of Grevena, Greece, where 266 disturbed soil samples were collecte...

The aim of this study is to develop an integrated approach to soil quality and fertility assessment in high-yielding rice agro-ecosystems threatened due to overexploitation of soil resources by intensive agriculture. The proposed approach is implemented considering representative pilot fields allocated throughout a study area based on the assumptio...

The aim of this study is to propose a new system for ranking models’ performance. The system is based on the standardized Ranking Performance Index (sRPI), which combines the results of any number and type of criteria from different simulation scenarios. The sRPI ranges between 0 and 1 (1 for the best and 0 for the worst performing model) based on...

It was investigated if differential genotypic tolerance of two pomegranate cultivars (‘Wonderful’ and ‘Acco’) to serpentine stress existed. For this purpose, pomegranate plants were grown outdoors, in three soil substrates (from parent material marl, serpentine and serpentinized peridotite). The results indicated that growth, most foliar nutrient c...

In this study, different interpolation techniques are presented, assessed, and compared for the estimation of soil iron (Fe) contents in locations where observations were not available. Initially, 400 soil samples from the Kozani area, which is near Polifitou Lake in northern Greece, were randomly collected from 2013 to 2015 and were analysed in th...

The amended soils chemical properties as affected by the application of a single dose of sewage sludge were evaluated over a 1-year period. Three soil groups based on their pH values were examined. Data on pH, organic matter, CaCO3, electrical conductivity, exchangeable Ca and Mg, concentration of nine metals (Cd, Co, Cr, Pb, Zn, Ni, Fe, Mn, Cu) an...

The amended soils chemical properties as affected by the application of a single dose of sewage sludge were evaluated over a one-year period. Three soil groups depending on pH values were examined. Data on pH, organic matter, CaCO3, electrical conductivity, exchangeable Ca and Mg and concentration of nine metals (Cd, Co, Cr, Pb, Zn, Ni, Fe, Mn, Cu)...

In this presentation the Greek NSDI trajectory for the period 2000-2013 is analyzed. For a comprehensive description of the subject, three time sub-periods are defined: The "pre-SDI era" (up to 2000), the "1st NSDI effort" (2000-2008) and the "2nd NSDI effort" (2008-2013). The first two sub-periods are presented with emphasis on the "1st NSDI effo...

The spatial representation of the soil properties for agricultural areas is necessary to implement precision agriculture management practices. This can currently be obtained by extensive sampling of soil or plants, which is laborious and not economical. An alternative procedure is presented in this study, where a digitized soil map was constructed...

The Soil Science Institute of Thessaloniki produces new digitized Soil Maps that provide a useful electronic database for the spatial representation of the soil variation within a region, based on in situ soil sampling, laboratory analyses, GIS techniques and plant nutrition mathematical models, coupled with the local land cadastre. The novelty...

The systematic inventory of soil resources constitutes a national, economic and social necessity for a country. The rational exploitation of soil resources should be supported by technical knowledge (e.g. soil studies), and should not be based entirely on the "experience" or empirical methods. Moreover, the new Common Agricultural Policy of E.U...

Spatial Data Infrastructure (SDI) is a long term, evolving process without a priori known results. Different countries try to develop a National SDI (NSDI) not always with a successful outcome. Although the successes are presented thoroughly (e.g. SDI best practice), it is equally important to highlight unsuccessful efforts in order to comprehensiv...