The growth dynamics in Brachiaria species according to nitrogen dose and shade.

PACIULLO, D. S. C.; FERNANDES, P. B.; GOMIDE, C. A. de M.; CASTRO, C. R. T. de; SOUZA SOBRINHO, F. de; CARVALHO, C. A. B. de; DOMINGOS SAVIO CAMPOS PACIULLO, CNPGL; PRISCILLA BELIGOLI FERNANDES, UFRRJ; CARLOS AUGUSTO DE MIRANDA GOMIDE, CNPGL; CARLOS RENATO TAVARES DE CASTRO, CNPGL; FAUSTO DE SOUZA SOBRINHO, CNPGL; CARLOS AUGUSTO BRANDÃO DE CARVALHO, UFRRJ.

The growth dynamics in Brachiaria species according to nitrogen dose and shade.

2011

PACIULLO, D. S. C. | FERNANDES, P. B. | GOMIDE, C. A. de M. | CASTRO, C. R. T. de | SOUZA SOBRINHO, F. de | CARVALHO, C. A. B. de | DOMINGOS SAVIO CAMPOS PACIULLO, CNPGL; PRISCILLA BELIGOLI FERNANDES, UFRRJ; CARLOS AUGUSTO DE MIRANDA GOMIDE, CNPGL; CARLOS RENATO TAVARES DE CASTRO, CNPGL; FAUSTO DE SOUZA SOBRINHO, CNPGL; CARLOS AUGUSTO BRANDÃO DE CARVALHO, UFRRJ.

It was studied the effects of shading (0, 36 and 54%) and of four nitrogen doses (0, 50, 100 and 150 mg N/dm³ of soil) on the morphogenetic traits and on the tillering of grasses of Brachiaria genus (B. decumbens, B. ruziziensis and B. brizantha cv. Marandu and cv. Xaraes), cultivated in pots with 5 kg substrate. It was used a complete random design, in a 3 × 4 × 4 factorial scheme with three replications. Nitrogen promoted increase in leaf appearance rate and in average leaf blade length, whereas shading increased stem elongation rate. Leaf elongation rate and tillering varied with the interaction among shading percentages and nitrogen doses. Shading increased response efficiency of leaf elongation rate to nitrogen doses, but reduced for tillering, evidencing priority existing tillering growth in detriment to appearance of new tillers when there is light restriction for the plants. Phenotypic adjustments, in response to light reduction, indicate that the studied grasses present tolerance to moderate shading.

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