Effects of Cutting Height and Rest Period on the Biomass of Urochloa brizantha cv. Marandú During Autumn in Concepción, Paraguay

Abstract

Improving pasture productivity largely depends on the appropriate management of rest periods. The experiment was conducted under field conditions in the community of Huguá Ocampo, Concepción District, Concepción Department, Paraguay, at an elevation of 168 m above sea level. The objective was to evaluate the influence of different cutting heights and rest periods on the biomass production of Urochloa brizantha cv. Marandú during autumn in Concepción District.  The experimentwas arranged in a randomized complete block design (RCBD) with eight treatments and three replications, resulting in 24 experimental units  and a 2 x 4 factorial arrangement. The factors evaluated were cutting height (15 and 30 cm) and rest period (30, 45, 60, and 90 days). The response variables measured were plant height, fresh biomass, dry matter biomass, leaf-to-stem ratio, and crude protein content. The analysis of variance showed highly significant differences between factor levels for plant height at 30, 45, and 60 days of rest, as well as for fresh biomass and dry biomass production. The highest biomass yields were obtained with the 90-day rest period, indicating that longer rest periods promoted greater forage accumulation. The leaf-to-stem ratio showed no significant differences among the treatments. Regarding nutritional quality, the highest crude protein content was recorded with a cutting height of 15 cm and a rest period of 45 days.  In conclusion, longer rest periods increased biomass production, whereas lower cutting heights combined with intermediate rest periods were associated with  a higher crude protein content.