Modelación del carbono, nitrógeno y azufre en la hojarasca foliar de hypericum phellosy miconia ligustrinaen un matorral altoandino:Pamplona-Colombia.

Abstract

The carbon, nitrogen and sulphur behaviors and temporal trends were modeled for the Hypericum phellos (Hp) and Miconia ligustrina (Ml) foliar litterfall within 20 years naturally regenerated high Andean shrub, in the Pamplona river basin by northeastern Colombia (3100-3250 m alt). Simple and multiple regression analysis were made, the time [days(𝑥) = 906] and meteorological factors being the independent variables. The percentage of foliar C, N and S were determined by complete combustion of the vegetal material with an oxygen direct flux at 1450 °C by December 2017, so, the released CO2 and SO2 were measured by means of a non-dispersive infrared rays detector, and the N2 was recorded according to thermal conductivity by a LECO TruMac CNS®. The C tended to decrease (HpC = -0,532ln(𝑥) + 62,032) and oscillate (MlC = -5E-08𝑥3 + 8E-05𝑥2 -0,0358𝑥 + 54,379); the N increased linearly and quadratically (HpN = 0,0004𝑥 + 1,1487; MLN = -1E-06𝑥2 + 0,0012𝑥 + 2,0614). The C/N ratio fluctuated (HpC/N = 2E-05𝑥2 - 0,0177𝑥 + 29,35) and decreased exponentially (MLC/N = 44,009e-3E-04x). The carbon behavior was explained by the mean temperature (HpC = 0,532(Tmed) + 50,701), the relative humidity and the evaporation (MlC = - 0,253(HR%) –0,037(Eva) + 73,807). The nitrogen was determined by the summation of the sunshine hours and the evaporation (HpN = 0,004(BSum) -0,007(Eva) + 2,284); by the mean evaporation and the wind (MLN = -0,228(Emed) + 0,43(Viento) + 1,546). The S was explained by the minimum temperature (HpS=0,314e-0,056(Tmin)); and the mean evaporation (MLS = 0,067(Emed)2 -0,472(Emed) + 0,932). The C/N ratio was like these: HpC/N = -0,056(BSum) + 0,085(Eva) + 26,072; and MlC/N = 4,996(Emed) -1,391(Tmin) + 34,193. H. phellos y M. ligustrina showed differential trends and behaviors allowing to segregate their functional niches.