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Sensitivity of the KANEAU irrigation management model applied to agroindustrial sugarcane complexes

Langellier P., Tediosi A., Letourmy P., Giner M.. 2009. Sugar Cane International, 27 (5) : p. 198-203.

KANEAU is an irrigation management software for agroindustrial sugarcane estates. Such farms, which consume considerable amounts of water in dry regions, call for a good command of water management. However, input parameters linked to the description of the environment, such as the soil available water and crop coefficients, needed to calculate the water balance, are often imprecise or tainted with errors. Aware that such imprecise data affects results, the authors endeavoured to determine the degree of accuracy required from these parameters. This article therefore describes the study of model sensitivity to variations in those parameters. An experimental plan was drafted based on simulations of ten-day irrigation rates previously applied in a sugarcane estate. Four input parameters for which estimation raised the most problems were studied: soil available water (SAW), crop coefficient Kc, potential evapotranspiration, and the Po coefficient. The effects of variations in those four input parameters were tested on two output variables: actual evapotranspiration (ETc adj) and the soil usable water stock (stock). Calculation of the derivatives of the output variable that defined sensitivity was replaced by measuring variation in the outputs with amplitudes approaching their imprecision. The root mean square deviation was used to measure the difference between a nominal curve and an arbitrarily modified theoretical curve. It was thus verified that climatological parameters had a much more limited impact on the model outputs than variations in the soil available water.

Mots-clés : saccharum officinarum; afrique

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