Effect of defoliation frequencies on the dry matter yield and nutrient content of two Centrosema species

• Autores: Jesus Faria-Marmol, David E. Morillo, Zuleima Chirinos
• Localización: Archivos Latinoamericanos de Producción Animal, ISSN 1022-1301, ISSN-e 1022-1301, Vol. 13, Nº. 1, 2005, págs. 13-18
• Idioma: inglés
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• Resumen

  • A trial was conducted to study the effect of three defoliation frequencies, at F1=4, F2=6 and F3=8 ¿ wk intervals, on dry matter yield (DMY), crude protein (CP) and mineral composition of Centrosema macrocarpum (Cm) and Centrosema pubescens (Cp). A split-plot experimental design with species (main plots), defoliation frequencies (subplots) and three replications was used. Samples for each defoliation frequency, corresponding to rainy (RS) and dry periods (DS), were analyzed for CP and calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K), copper (Cu), iron (Fe), and manganese (Mn) concentrations. DMY of Cm (4.4 t ha-1year-1) was higher (P<.05) than of Cp (1.5 t ha-1year-1). DMY increased (P<.05) with increasing cutting interval (F1=2.4, F2=2.5 and F3=3.6 t ha-1), whereas CP, ash, and most mineral concentrations were not affected (P>0.5). Only Ca declined (P<0.05) with increasing plant maturity. Ca and P concentrations were affected by season (P<0.05). In Cm, Ca concentrations during RS (1.27%) were lower than in the DS (1.55%), whereas in Cp, P concentrations were higher (P<0.05) in RS (0.25%) than in DS (0.21%). In both species, Fe, Cu and Mn concentrations decreased (P<0.05) during RS. Other elements were not affected (P>0.05) by season. Mineral concentrations of the two species were adequate to cover grazing ruminant nutritional requirements with the possible exception of P (0.21%). Forage P concentrations may have been influenced by the low soil P content. Ash and Cu concentrations were lower (P<0.005) in Cm than Cp but CP and mineral composition did not differ between species. (Text in English).