Asociación Latinoamericana de Producción Animal (ALPA)
Abstract
The architecture and phenology of the species Prosopis juliflora (Pj) and Acacia tortuosa (At) was evaluated in a semiarid environment with temperature of 29 °C’s, evapotranspiration of 1708 mm, and rain fall of 540 mm, annual mean. A conglomerate of five mature individuals for species was selected, from a three ha exclusion area of natural forest. In each individual, it was measured the diameter, area of the cop, and the type and order of present branches. Also, fifteen productive branches were identified and evaluated to intervals of 34.7 ± 1.7d during one year. A total of 1560 observations of accumulated diameter (D) and length of the branch (L), number of buds (NDY), of leaves (NDH), and of buds with leaves (YCH) was subjected to an ANOVA using three statistical models and the "Proc GLM" of SAS. The effects specie: Si, i = 1, 2; individual within specie: I(S)ij, j = 1,. . . ,5 in both species; time: Tk, k = 1,. . ,11; order of branch: Ol, l = 1,. . .,6; branch: Rm, m = 1,. . .,15; and the interaction species x time: STik were common to all models. The Model for D included, in addition, the lineal effect of initial diameter; that of L the lineal effect of initial length, and the lineal and quadratic effect of D; and that of NDY, NDH, and YCH D and L lineal and quadratic as covariables. For D, L, and NDH, ST was not significant. The least square means for the given order variables are listed and for species were of 4.3 ± 0.04 vs 4.2 ± 0.04, 35.0 ± 0.7 vs 38.1 ± 0.6, 24.7 ± 0.4 vs 30.7 ± 0.4, 24.7 ± 0.4 vs 30.7 ± 0.4, 14.1 ± 0.4 vs 15.5 ± 0.4; and the density of one unit of NDY, NDH, and of YCH for each 1.5 vs 1.3, 1.4 vs 1.2, and 2.9 vs 2.2 cm’s length in Pj and At respectively. The increment in D was bigger in Pj, and the increase in L was of 9.05 ± 0.92 with a quadratic tendency of 0.31 ± 0.07 cm for each mm of increment in D, and it was bigger in At. Blooming of Pj reached top in the dry season, and that of the At at the beginning of the spring. The architecture was similar, in both species as for height, and diameter and area of the cop. Branches of order VII and IX were observed in Pj and At, respectively. The results are indicative that both species Pj and At have a complex architecture that is a characteristic of foragers arboreus species. However, the foliar components of DM seem to differ among them, with certain specie x season interaction. The Pj seems to have bigger activity during conditions of stress hydric, while the At responds better to moisture seasons
