Mineral concentrations in leaves and stems of various forages of the Colombian paramo

Abstract

A study was conducted to determine the elemental composition of two plant fractions (leaves and stems) of several forage species in three sheep farms of the paramo in Colombia. The elemental composition of the forage species, and the relationship between soil chemistry and the elemental composition of the forages were also determined. Sampling periods corresponded to the end of the rainy season (May‐June 1987), and the middle end of the dry season (February 1988). Leaves were higher (P<0.05) than stems in the following: calcium, phosphorus, magnesium, potassium, iron, molybdenum, crude protein, and IVOMD. Overall percentage of deficiencies were related to the requirements for sheep as follows: calcium (88%, 13%), phosphorus (50%, 27%), magnesium (85%, 41%), potassium (13%,3%), sodium (94%, 96%), iron (10%, 4%), copper (82%, 65%), manganese (7%, 0%), zinc (46%, 42%), cobalt (92%, 85%), selenium (77%, 65%), crude protein (45%, 8%) for stems and leaves, respectively.

Based on analyses, elemental, crude protein and IVOMD concentrations of forage species, tended to differ. Soil‐forage correlation coefficients of the same mineral for the rainy season were calcium (r = 0.81), magnesium (r = 0.89), potassium (r = 0.71), zinc (r = 0. 69). For the dry season, correlations were calcium (r = 0.61) and magnesium ( r = 0.58). Results indicated low correlation coefficients between most soil and forage elements, and that they are not of great value in assessing the elemental status of grazing sheep in the paramo.