A simple method for determining maize silage density on farms

Several methodologies have been tested to evaluate silage density, with direct methods most popular, whereas indirect methods that can be used under field conditions are still in development and improvement stages. This study aimed to establish relationships between estimates of maize silage density determined using a direct and an indirect method, in an endeavor to provide an alternative to direct measurement for use in the field. Measurements were performed on maize silage in 14 silos. The direct method involved the use of a metal cylinder with a saw-tooth cutting edge attached to a chainsaw to extract a core of silage. Density of the silage was determined taking into consideration the cylinder volume and dry matter weight of silage removed at 5 points on the silage face. With the indirect method, a digital penetrometer was used to estimate silage density by measuring the penetration resistance at 2 points adjacent to the spots where the silage cores were taken, i.e. 10 readings per silo. Values of penetration resistance (measured in MPa) were correlated with the values of silage mass (kg/m3) obtained by direct measurement through polynomial regression analysis. A positive quadratic relationship was observed between penetration resistance and silage density for both natural matter and dry matter (R² = 0.57 and R² = 0.80, respectively), showing that the penetrometer was a reasonably reliable and simple indirect method to determine the density of dry matter in maize silage. Further testing of the machine on other silos is needed to verify these results. Keywords: Ensiled matter, penetrometer, resistance, silos evaluation.