Friability and its relationship with some physical and chemical soil properties under sugar cane crop

espanolLa friabilidad es un indicador importante de la calidad fisica de los suelos y su comportamiento esta ligado a la variabilidad de otras propiedades edaficas. El objetivo de esta investigacion fue evaluar la relacion de la friabilidad con diferentes propiedades fisicas y quimicas de suelos cultivados con cana de azucar. El muestreo de suelos se realizo en los dos primeros horizontes (Ap y A1) de 91 sitios correspondientes a 5 ordenes de suelos (Inceptisol, Molisol, Vertisol, Alfisol y Ultisol). Se seleccionaron 10 agregados por cada uno de los cuatro rangos de tamano (2,0 a 4,79; 4,80 a 9,49; 9,50 a 19,00 y 19,01 a 35,70 mm) que fueron los predominantes en los 182 horizontes. Los 7280 agregados fueron secados en invernadero y horno y posteriormente sometidos a compresion para determinar la resistencia al rompimiento (RR) y el indice de friabilidad correspondiente al limite inferior (IFi) del intervalo de confianza del coeficiente de variacion. Se determino el diametro ponderado medio (DPM), el estado de agregacion (Ea), la densidad aparente (Da), la porosidad total (Pt), el pH y la conductividad electrica (CE) de las muestras de suelos. Se utilizaron medidas de tendencia central y dispersion, graficos de superficies tridimensionales y un modelo lineal para un Diseno Completamente al Azar en arreglo factorial incompleto. No se encontro efecto del DPM, la Da, el pH y la CE sobre el IFi, pero si del Ea y la Pt. Los valores del IFi se incrementaron a mayor porosidad total y a mayor estado de agregacion. EnglishFriability is an important indicator of the physical quality of soils and it is linked to the variability of other edaphic properties. This study aimed to evaluate the relationship between friability and different physical and chemical soil properties cultivated with sugar cane. The sampling was carried out in the first two horizons (Ap and A1) of 91 sites corresponding to five soil orders (Inceptisol, Molisol, Vertisol, Alfisol and Ultisol). Ten aggregates were selected for each of the four ranges (2.0 to 4.79, 4.80 to 9.49, 9.50 to 19.00 and 19.01 to 35.70 mm) that predominated in the 182 horizons. The 7,280 aggregates were dried in a greenhouse and an oven; subsequently, subjected to compression to determine the compressive strength (CS) and the friability index that corresponded to the lower limit (FIi) of the confidence interval of the variation coefficient It was determined the mean weight diameter (WMD), the aggregation state (AS), the bulk density (AD), the total porosity (TP), the Ph, and the electrical conductivity (EC) of the soil samples. In addition, measurements of dispersion and central tendency, three-dimensional surface graphs, and a linear model were used with a completely random design using an incomplete factorial arrangement. No effect was seen from the WMD, AD, pH, or EC on the FIi; however, the AS and the TP had significant effects from the inferential point of view.