[Show abstract][Hide abstract] ABSTRACT: Agro-ecozoning is a delineation of landscape into relatively homogeneous regions of expected similar crop performance. Past classifications have been subjective, crop specific and did not take into account spatial correlation. A quantitative approach is proposed to unambiguously locate, characterise and visualise agro-ecozones and their boundaries which can be allied to different environmental conditions. In this study the environmental parameters, including climatic and soil characteristics, hypothesized to be generally relevant to many crops in Capitanata-Foggia (South Italy), were used. Cokriged environmental estimates at 500 m scale were used in a clustering algorithm based on non-parametric multivariate density estimation. A 3D map of density estimation and red-green-blue colour triplet were used for visualisation of agro-ecozones as a unique combination of environmental factors. The proposed approach produced the delineation of the study area in five compact classes in the space of environmental attributes that were also contiguous in geographic space. The resulting agro-ecozones may provide a framework for useful application in land use decision making.
[Show abstract][Hide abstract] ABSTRACT: An efficient management of water resources is considered very important for Mediterranean regions of Italy in order to improve the economical and environmental sustainability of the agricultural activity. The purpose of this study is to analyze the components of soil water balance in an important district included in the regions of Basilicata and Puglia and situated in the Jonical coastal area of Southern Italy and mainly cropped with horticultural crops. The study was performed by using the spatially distributed and physically based model SIMODIS in order to individuate the best irrigation management maximizing the water use efficiency and minimizing water losses by deep percolation and soil evaporation. SIMODIS was applied taking in to account the soil spatial variability and localization of cadastral units for two crops, durum wheat and water melon. For water melon recognition in 2007 a remote sensed image, from SPOT5 satellite, at the spatial resolution of 10 m, has been used. In 2008, a multi-temporal data set was available, from SPOT5 satellite to produce a land cover map for the classes water melon and durum wheat. Water melon cultivation was simulated adopting different water supply managements: rainfed and four irrigation strategies based on (i) soil water availability and (ii) plant water status adopting a threshold daily stress value. For each management, several water management indicators were calculated and mapped in GIS environment. For seasonal irrigation depth, actual evapotranspiration and irrigation efficiency were also determined. The analysis allowed to individuate the areas particularly sensitive to water losses by deep percolation because of their hydraulic functions characterized by low water retention and large values of saturated hydraulic conductivity. For these areas, the irrigation based on plant water status caused very high water losses by drainage. On the contrary, the irrigation scheduled on soil base allowed to control better this component of soil water balance. SIMODIS resulted a useful tool to analyse the soil water balance at spatial scale and to support the local irrigation authority for planning the irrigation water distribution.
Italian Journal of Agronomy. 01/2010; 5(2):193-204.
[Show abstract][Hide abstract] ABSTRACT: Agricultural fields naturally have within-field variations that may cause spatial variability in crop yields. Delineating a field into a few management zones (MZ) is therefore a practical management approach for precision agriculture. In this study, some soil properties (clay content, organic matter content and water content measured at different dates) and a multivariate geostatistical approach were used to delineate management zones. The temporal stability of soil water content spatial patterns may be an additional approach in delineating management zones. The present study was conducted on a 120000 m2 durum wheat field in Southern Italy, where soil properties and soil water content were measured at different times over three crop seasons (2005-06, 2006-07, and 2007-08) at 100 locations. The multivariate spatial and temporal data were analysed by Factor Kriging Analysis (FKA). All simple and cross model variograms were calculated by fitting a linear model of coregionalization including the nugget effect and two spatial structures at shorter (70 m) and longer range (500 m). The application of factor kriging allowed us to identify one regionalized factor at longer scale and to partition the field from the point of view of temporal stability of soil water content, into contiguous zones to be submitted to site-specific management. The method showed a great flexibility to combine data from several sources in the delineation of management zones.
[Show abstract][Hide abstract] ABSTRACT: Modelling spatial variability of environmental parameters through the application of modern techniques of geostatistics has permitted to acquire elements apt to evaluate the possibility of using Natural Attenuation as a remediation technique for groundwater contaminated by chlorinated compounds. Moreover, a precise delineation of hazardous areas in a polluted site is strongly based on accurate predictions of contaminant concentrations, a task that is complicated by the presence of censored data and highly positively skewed distributions. The present paper proposes a geostatistical approach that includes different methods for the study and the control of the ongoing activity of Natural Attenuation in an abandoned industrial area. The considered variables in this application are the values of concentration in groundwater of some aliphatic chlorinated carcinogenic compounds (PCE and TCE), measured in numerous piezometers, which show highly skewed distributions, characterized by a considerable number of values below the detection limit of the instrument. Indicator Kriging has been applied and the areas with 90% probability of exceeding the detection limit have been considered, inside which the variables were transformed through Gaussian Anamorphosis. The application of geostatistics has put into evidence the existence of a correlation between them not only from the chemical point of view, but also from the point of view of their spatial distribution: the shared presence of "hot spot" areas might be imputed to the existence of localized hazard sources. In those areas it is possible to detect coherence between the concentrations of the contaminants in study and the distribution of the parameters that control the phenomenon, which might be considered a clue that the degrading chemical activity is in progress. Successively, some punctual considerations have been done on the basis of the concentration values of contaminants coming from a following sampling plan on the same area, in order to verify this result. At the same time, an analytical model has been implemented to quantify the Natural Attenuation.