Harvest Frequency and Stubble Height Affect Herbage Accumulation, Nutritive Value, and Persistence of ‘Mulato II’ Brachiariagrass

Abstract

‘Mulato II’ (Brachiaria sp.) is a warm-season forage hybrid with superior nutritive value introduced in Florida in 2003. The objective of this study was to evaluate the effects of harvest frequencies and stubble heights on herbage accumulation (HA), nutritive value, and persistence of Mulato II brachiariagrass. The research was conducted in Ona, FL (27°N) from August to October 2007 and 2008. Treatments were the factorial combination of 2- and 4-week harvest frequencies and 1-, 3-, and 5-inch stubble heights with four replicates in a randomized complete block design. Plot size was 9.8 × 6.5 ft with 3.0 ft between plots. There was a quadratic decrease in HA from 1,800 to 1,400 lb/acre with increasing stubble heights. Conversely, herbage crude protein (CP) and in vitro digestible organic matter (IVDOM) increased linearly with decreasing stubble heights (from 17% to 14% and from 67% to 66% for CP and IVDOM, respectively). There were significant season effects on responses as HA decreased and nutritive value increased from September to November for both harvest frequencies. Mulato II ground cover linearly increased from 74% to 87% as stubble height increased from 1 to 5 inches. Despite greater HA and nutritive value, short stubble heights in combination with 2-week harvest interval decreased the persistence of Mulato II and should be avoided.