Eficiência do uso da radiação solar na produção de forragem de trigo duplo-proposito

Abstract

The objective of the study was to evaluate the efficiency of the use of solar radiation in the production of double-purpose wheat forage. The trial was conducted in the experimental area of the Federal University of Pampa-Campus Itaqui, RS, and two experiments were carried out in subsequent years (2018 and 2019) evaluating dualpurpose wheat (Triticum aestivum L) cv. BRS Tarumã. Both were carried out in a randomized block design, with four replications and treatments consisting of sowing dates. In experiment 1 (2018) sowing took place on April 13, May 22, June 20 and July 2018. In experiment 2 (2019), sowing dates were April 9, June 8, August 1 of September 6 . Successive cuts were made taking into account the heights reached by the forage canopy, adopting the cutting height of 30 cm and leaving a residue of 50% of the cutting heights. Forage production (kg DM ha-¹) and the number of days between cuts were evaluated. Two calculations were performed, where the production of the total dry mass MST (kg MS / ha) was calculated, which was divided by the average daily temperature (° C) over the long period from sowing to the first cut and so on. The production of the total dry mass MST (kg MS / ha) was also calculated by the average solar radiation (cal / cm²). There was great variability in the efficiency of the use of radiation, which in 2018 was greater than in 2019, with sowing effect.