[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: 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.