Resumen

CAMACARO, Selina; CHACON, Eduardo  y  MACHADO, Wilfre. Effect of Fertilization with macro and micro-Nutrients on the Biomiss Production of Leucaena leucocephala (lam) dewit. Zootecnia Trop. [online]. 2002, vol.20, n.2, pp.163-178. ISSN 0798-7269.

An experiment was carried out at "La Antonia" Experimental Research Station of the Central University of Venezuela, located in Marin, Yaracuy (10º 22 ' 28" N and 68º 40 ' 45" W), with the objective of evaluating the effect of the fertilization with macro and micronutrients on the structure and the production of biomass of Leucaena leucocephala. "La Antonia" Experimental Research Station is located on an area of transition of tropical humid forest and tropical dry forest. The legumes plots were established in 1996 in single rows of 1x 2 m, on a pasture of Cynodon sp. The limiting elements were detected according to soil analysis (K: 32 ppm; Mg: 12 ppm; Cu: 0 ppm; Zn: 1.5 ppm; pH: 5.16). An aleatory blocks design was used, with sixteen treatments, including two controls (negative and positive), as a result of combining the nutriments K, Mg, Cu, and Zn elements with a missing element, applied at doses of 70, 20, 3 and 3 kg/ha, respectively. Before each non-destructive sampling (ending of rains, November 97; drought, March 98; rains, Julio 98 and endings of rains, November 98), a destructive sampling was done on 10 plants (not included in the experiment) to generate multiple regression equations to estimate the production of biomass. The evaluated variables in these destructive samplings were: height (AP), number of branches (NR), length of branches Ø < 6 mm (L <), length of branches Ø > 6 mm (L >), number of leaves (NH), length of leaves (LH), branches dry matter Ø < 6 mm (MST <), branches dry matter Ø > 6 mm (MST >) and leaves dry matter (MSH). The variables evaluated in the non - destructive samplings were the same ones mentioned previously, except for the variables dry matter of, leaves and dry matter branches Ø < 6 mm and Ø > 6 mm, respectively. The  production of edible biomass was affected (P < 0.05) by the treatments, but not the non-edible biomass (MST >) (P>0.05). Differences were detected (P < 0.05) for the variable MSH among the treatment 1(8.49 g/branch) and the treatments 3 (4.90 g/branch), 6 (4.76 g/branch), 9 (5.63 g/branch) and 13 (5.76 g/branch), but there were not differences (P>0.05) between the first one and the rest of the treatments. The variable MST < showed differences among the treatment 1(4.86 g/branch) and the treatments 3 (3.22 g/branch) and 6 (3.22 g/branch), not detecting differences (P>0.05) among the treatment 1 and the rest. The precipitation had a decisive effect in the biomass production, reachinf the biggest values at tme end of rains (1057.90 kg MS edible/ha) and rains (817.50 kg MS non edible/ha). It is discussed about the importance of the results in view of the scarce information in this topic existent in Venezuela and the necessity of continuing the investigation combining different elements at different levels, using experimental designs that allow to approach the analysis of the obtained information accurately.

Palabras clave : Leucaena leucocephala; Fertilization, Biomass Production; macro nutrient; micro nutrients.