Abstract
The need to know the drainable porosity of the soil or macro porosity in order to correctly manage the water in the soil, whether it is for irrigation purposes or for drainage purposes, has taken on increasing relevance. For this there are equipment that is offered in commercial houses, usually with high costs. However, knowing the physics of water in a sandy matrix, you can build a suction table (tension table) with sand commonly called sandbox to estimate the macro and micro porosity and as such the total porosity present in a soil. The micro porosity obtained for a sandy soil subjected to a suction of 60 cmca (centimeters of water column) and 100 cmca were 11,12% and 5,73% of gravimetric humidity and the macro porosity obtained and expressed in terms of percentage of gravimetric humidity ((gwater/gsoil) * 100) for a sandy soil subjected to a suction of 60 cmca and 100 cmca were 25,14% and 30,53%.
Keywords: Macro porosity; micro porosity; gravimetric humidity percentage; volume humidity percentage