DISTRIBUCIÓN DE LA POROSIDAD DE UN SUELO FRANCO ARCILLOSO (ALFISOL) EN CONDICIONES SEMIÁRIDAS DESPUÉS DE 15 AÑOS BAJO SIEMBRA DIRECTA.

On along-term essay under direct drilling, the evolution of the physical properties of a clay loam soil, such as distribution by origin of soil porosity, has been assessed during two growing seasons. The grain crops in each growing season were spring barley and winter barley, respectively. Soil physical properties were measured on a 2 m length transect located on a perpendicular line to the direction of vehicular traffic for field operations. Five sampling opportunities in each crop cycle, were used to measure the variables. Structural soil porosity, due principally to shrinkage and swelling cycles, was assessed in the 0 to 35 cm depth soil profile. This natural process seemed to be sufficient to guarantee good drainage and normal crop development, unless in the moisture content range included in field capacity. [ABSTRACT FROM AUTHOR]