Propiedades físicas de sustratos, base de los sistemas agrícolas urbanos

Abstract

In the same way that the soils physics is the basis of the improvement of the soils, the substrates physics constitutes the essence of the success of the urban agricultural systems. The organic matter, main component of the substrates, is rich in nutritious, and so that the cultivations assimilate the same ones appropriately, it is required a good correlation of the solid, liquid and air phases. The physical characteristics were determined (density of the solid phase, bulk density, porosity, bulk contraction and hidro-physical (properties of retention of water) to substrates and its combinations, commonly used in organopónicos, intensive orchards, houses of production of postures and ornamental, fruit-bearing and forest viveros. It´s showed, the worm humus and the coconut fiber have good results in what concerns to the good thresholds of air and easily available water. In the mixtures with soils, as the content of organic matter increased, it diminished the density of the solid phase and the retained water was increased. The curves of retention of humidity are the reflection of the physical behavior of the substrates. It is recommended to improve the institutional capacity of the laboratories of physics of soils and substrates to perfect the system of urban agriculture in the country.