Difference in the dry matter content of lucerne soilage harvested in the morning in relation to afternoon cut

Ignacio Ruiz N.1, Fernando Medina V.2 y Susana Muñoz M.2

During 42 weeks, from November 1990 to October 1991, except June and July, at La Platina Experimental Station (INlA), Santiago, a sampling was conducted in order to evaluate the changes in dry matter content of lucerne (Medicago sativa L.) chopped in the morning (around 08:30 to 09:30) and in the alternoon (13:30-14:30 hr). Forage samples, taken at leeding time, were ovendried at 65 ºC. Sampling was only carried out in days with no rain influence. During all weeks the dry matter content of the alternoon harvest was higher than the morning cutting. The lowest difference was detected in April (8.5%) and the highest in September (27%). As average, the foliage dry matter cantent was 17.2% in the morning against 20.4 in the afternoon; the difference of 3.2 units (18.6%) was significant lor "t" test (P < 0.05%). From the results two aspects are to be considerad: First, in experiments using soilage, two daily cuts must be done at least, so it's necessary to measure moisture of the forage on each opportunity. By using only data from the morning or from the afternoon, an average of 8.5% of under or over estimation would be reached olthe daily forage offered. These data change during the year, being 4.1% in April and 11.9% in September. Secand, in a dairy farm, in cases where soilage is offered in fixed amounts, split in 2 daily feedings, a mislead may occur in estimating the forage dry matter intake (then in the nutrients balance) if the moisture content is asumed to be constant throughout the day.

Keywords: lucerne, soilage, dry matter content.
1 Estación Experimental La Platina (INlA), Casilla 439, Correo 3, Santiago, Chile.
2 Facultad de Ciencias Agrarias y Forestales, Universidad de Chile, Casilla 1004, Santiago, Chile.