DIAGNOSIS OF THE PROPERTIES OF SOILS IN FOREST AND PRODUCTIVE AREAS OF THE EL TRIUNFO BIOSPHERE RESERVE

Abstract

The study was carried out in a representative micro-basin of the El
Triunfo Biosphere Reserve (Reserva de la Biósfera El Triunfo, REBITRI),
with the purpose of evaluating the situation present in the properties of
the soils under three types of use. Eighty-three (83) sites were studied, of
which 49 were soils cultivated with Zea mays L.; the variables analyzed
were: soil acidity, organic matter, cationic exchange capacity (CEC),
content of phosphorus, basic cations (Ca, K, Mg, Na), micronutrients (B,
Cu, Fe, Mn and Zn), apparent density (g cm^3-1), porosity (%), and speed
of infiltration. They were determined and interpreted according to the
NOM-021-SEMARNAT 2000 (DOF, 2002), while the physical properties
were determined through the cylinder method recommended by
the Natural Resources Conservation Service of the United States
Department of Agriculture (USDA, 1999); with these data, measures
of centrality and dispersion were obtained, through which hypothesis
tests were made, and correlation and regression analyses. The results
showed significant differences between soils with forest coverage
compared to those cultivated with coffee and maize; the latter
presented the highest levels of degradation. The speed of infiltration
was significantly higher in soils with forest, confirming the importance
of the reserve as a zone of water recharge. The soils cultivated with
maize were the least deep and the only ones that did not present the
horizon “A” (characterized by the dark color from organic matter), due
to the process of hydric erosion and the small contribution of organic
matter that they’ve had during their exploitation. It is concluded that
maize and coffee soils require a management program to recover and
maintain their productive capacity, due to the constant washing from
hydric erosion, and to the lack of replacement of nutrients extracted
by the harvests.