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Water retention curve (WRC) is analyzed by means of the fractal geometry approach. Three models accounting for the fractal distribution of either the pore and solid phase of unsaturated porous media have been considered. By using data collected during a field scale internal drainage, we determine the functional relationship between the WRC, and the fractal dimension(s). In particular, it is shown that the fractal scaling of the WRC is feasible provided that a large enough set of measurements at the lowest water contents is available. (C) 2013 The Authors. Published by Elsevier B.V.

Strategies to improve cereal yield in Terai (Nepal) were developed with AquaCrop by simulating different scenarios of irrigation and fertilizer management for three dominant soil types with 30 years historical climatic data. Farmers yield increased from 25 to 115% depending on soil type, fertility and irrigation level. Considering the low availability of irrigation water and fertilizers, use of deficit irrigation with 1/4 of the net irrigation requirement (Inet) and fertilizer application below 50% of national recommended fertilizer dose (NRFD) was regarded as the most suitable strategy. For fertilizer applications above 50% of NRFD, deficit irrigation with 1/3 Inet is recommended. ispartof: pages:767-775 ispartof: Procedia CIRP vol:19 pages:767-775 ispartof: International Conference on Four Decades of Progress in Monitoring and Modeling of Processes in the Soil-Plant-Atmosphere System location:Naples, Italy date:19 Jun - 21 Jun 2013 status: published

Efficient water resources management is an issue of major importance in the field of sustainable development, especially in the agricultural sector which represents the main consumer through irrigations. Therefore irrigation management is an important and innovating area which was the subject of several research and studies. Modeling, and more particularly, the Agent-Based Modeling (ABM), allows better representing the multiplicity of these actors, the diversity of their roles and their interactions. The main reason why we chose the agent technology in the field of gravity irrigation systems, is the complexity to manage in real-time the water distribution operations those arrive asynchronously and dynamically and to be reactive and adaptive to the dynamic and unpredictable events that characterizes the field (mainly rainy advents). Our objectives are mainly located on two levels. The first one, concerns the gravity irrigation modeling by a multi-agent technology and the agent modeling through AML language. The second one focuses on the irrigations scheduling optimization using an evolutionary algorithm. Comparisons between schedules before and after optimization are made and the results shows that our approach can be considered as an efficient tool for planning irrigation schedules by considering crops water needs.

This paper presents an overview of a decade (2002-2012) of studies performed on Soil-Plant-Atmosphere processes, in semi-arid areas (Haouz plain, Morocco). In this period, fifteen in-situ experiments on the dominant irrigated crops were performed, controlling the fluxes exchanged between land surface and atmosphere. The results showed that the physically based SVATs (ICARE, SiSPAT and ISBA) provided the best estimates of surface fluxes. For operational purposes, the FAO-56 approach and SAMIR Software (Satellite Monitoring for Irrigation) give a good estimate of evapotranspiration at field and regional scales, respectively. Finally, thermal infrared data were used in conjunction with SVATs to investigate the possibility of estimating the quantity of irrigation water.

A mixed procedure, referred to as CN4GA (Curve Number for Green-Ampt), was recently introduced with the aim of distributing in time the net rainfall volume provided at event scale by the Soil Conservation Service - Curve Number (SCS-CN) method. The proposed method consists in employing the Green-Ampt infiltration equation and calibrating both the ponding time and the soil hydraulic conductivity using the initial abstraction and the total volume given by the SCS-CN method. The procedure is here applied on several rainfall-runoff events observed in an Italian watershed. Results confirms the general behavior already noticed in previous studies: the CN4GA procedure provides net rainfal intensities consistent with the runoff observations, the SCS-CN method underestimates peak intensity when applied at sub-daily * resolution, and the differences between the two approaches are relevant when the gross rainfall peak occurs at the beginning of the storm and generally in case of multi-peak events.

An accurate and high-resolution description of the spatial variability of soil water content at the field scale and the distribution of water in the unsaturated zone requires a large number of measurements. Financial and time constraints limit the numbers of measurement locations; thus the standard approach for monitoring could lead to a large degree of uncertainty in spatial predictions. We test in a parcel of bare soil an alternative approach based on ground-based geophysical techniques, by comparing the monitoring of the soil water content obtained from the Electrical Resisitivity Imaging and the Ground Penetrating Radar with the variability maps estimated from the interpolation of soil water contents measured in different locations With capacitance probes. The agreement is good and the integration of the techniques is promising. (C) 2013 The Authors. Published by Elsevier B.V