Multi-Local and Multi-Global Sensitivity Analysis of Soil Hydraulic Properties: Case of Study of Hydraulically Restrictive Layer.

Water management on a crop farm requires intelligent irrigation and drainage strategies to sustain strong productivity and minimize environmental impact to give a better water productivity. Irrigation scheduling based on soil water potential thresholds is current practice in crop production. However, the water management needs to have a perfect control of drainage condition in order to avoid water excess during too long periods of time for limit the spread of disease and waterlogging. Several observations in crop fields have identified the presence of soil horizons that have restrictive flow hydraulic properties in multi-layered soils affecting the capacity to maintain a targeted matric potential. It is therefore necessary to identify the conditions (hydrodynamic, physical and climatic) that can produce drainage problems caused by hydraulically restrictive layer. This communication presents a multi-local and multi-global sensitivity analysis on hydrodynamic, physical and climatic conditions. Soil water flux dynamic was simulated with finite element model Hydrus 1D (Šimůnek et al., 2008). After the numerical simulations a sensitivity analysis was performed on soil matric potential at 10 cm of depth based on the procedure described by Cheviron et al. (2010) and with variance analysis. This study has identified combinations of soil conditions which cause significant reduction of a drainage capacity affecting the capacity to maintain a targeted matric potential in a root zone. Now a better understanding of soil conditions may cause phenomena that lead to phenomena such as a perched water table can make the diagnosis more easily using data soil matric potential and characterization of soil hydraulic properties.

References:

Cheviron, B., S.J. Gumiere, Y. Le Bissonnais, R. Moussa and D. Raclot. 2010. Sensitivity analysis of distributed erosion models: Framework. Water Resources Research 46: W08508. doi:10.1029/2009WR007950.

Šimůnek, J., M.T. van Genuchten and M. Šejna. 2008. Development and Applications of the HYDRUS and STANMOD Software Packages and Related Codes. Vadose Zone J. 7: 587-600. doi:10.2136/vzj2007.0077.