Journal of NACAA

Brachiaria (Urochloa) Cultivar Response to Nitrogen Fertilizer as A Summer Forage Crop in the Southern USA

ISSN 2158-9429

Volume 16, Issue 2 - December 2023

Editor: Linda Chalker-Scott


Brachiaria (Urochloa) is a tropical perennial warm-season grass that could be used as a summer forage, but little is known about its production and fertilization requirements in the southern USA.  The objective of this study was to determine forage biomass production of Brachiaria (Urochloa) spp. under different fertilization regimes.  The study was conducted at Mississippi State University on a Marietta sandy loam.  The experimental design was a randomized complete block design with a split-plot arrangement replicated three times.  The main plots were four nitrogen (N) rates applied at 0, 60, 90, and 120 lb N ac-1 in split applications using urea ammonium sulfate (33-0-0-18S).  The subplots were two cultivars, ‘Basilisk’ (Urochloa decumbens) and ‘Mulato II’ (Urochloa ruziziensis x U. brizantha x U. decumbens).  Cultivars were established on July 12, 2022, in a prepared seed bed at 10 lbs PLS (Pure Live Seed) ac-1.  Seasonal biomass response indicated that a N application of 60 to 90 lb N ac-1 yr-1 is optimal.  There were no differences in nutritive value among cultivars except for CP, where MUII had an 11% greater concentration.  Leaf area index was maximized at 70 lb N ac-1.  Green canopy cover and NDVI were 41 and 23% greater, respectively, during the second harvest.

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