Nitrogen nutrition index and morphogenesis in Alexandergrass of the Central Depression of Rio Grande do Sul

ABSTRACT: This study assessed the nitrogen nutrition index, morphogenic characteristics and tiller structure of Alexandergrass (Urochloaplantaginea (LINK) Hitch) pasture submitted to different (N) levels (zero, 150 or 300 kg ha-1 N). The experimental design was entirely randomized with repeated measures arrangement. animals were Angus heifers under rotational stocking grazing method. number variable keep 30±5 cm post-grazing sward height. Nitrogen index increased linearly according N (Ŷ = 59.8 + 0.1216N; P < 0.0001; r²=0.53). leaf appearance rate adjusted a positive linear regression model thermal sum (TS) zero (Ŷ0N 0.0077 0.0000087TS; 0.0308; r² 0.72) (Ŷ150N 0.0020 0.000021 TS; 0.0022; 0.92). use did not alter (0.0124 degree-days-1). up increases content. in is modified using while expansion, stem phyllochron, lifespan, elongation duration are altered by utilization.