This work aims at modeling quantitatively the effects of a mulch on the water and heat transfers in the soil-mulch-atmosphere system. The developed model TECmulch derives from the mechanistic model TEC, designed for bare soil. TECmulch accounts for (1) free convection, (2) forced convection, and (3) radiative transfer in the mulch. The mulch formalism does not rely on the classical local gradients theory but on long-distance exchanges. It is based on four parameters that are calibrated on experimental data for two different mulches (corn residue and crushed glass). Experimental data come from la Tinaja's station (Mexico) for corn mulch and Avignon's station (France) for glass mulch. Measurements concern the physical characterization of the soil and the mulch, the evolution of soil water content and temperature, and the radiative balance plus usual climatic data. TECmulch is validated on independent data, compared to the classical theory, and each modeled process is analyzed in detail.