Carbon labile pool in Chilean volcanic soils

Gilda Borle B.1, Silvia M. Aguilera S.1, Pedro Peirano V.1 y Mario Calozzi M.1

Carbohydrates (CH) are the labile pool of organic matter (OM). From an agricultural point of view, they play an important role in productivity because of their manyfold contributions and roles: regulators of biological activity, soil aggregation, water retention in the rhizospheric area, nutrient solubility and movilization. There are soluble or readily available CH and more stable or hydrolized ones. Since both fractions are essential for the edaphic system, they were evaluated in seven representative soils: three trumaos, two rojo-arcillosos and two nadis, that were subjected to different agricultural work. In addition, determinations were made of dehydrogenase activity and total available P content. Small amounts of soluble and hydrolized CH were found in spite of bibliographic in information on the contrary. They are closely related to OM content. The CH content is low in forest soils, higher in native prairies, but it lowers with fertilization and cultivation. This decrease of the labile pool is closely related to biological activity. No measurable relation was found for P content probably because of the fertilizer added.

Keywords: labile pool, volcanic soils, organic matter, carbohydrates.
1 Facultad de Ciencias Químicas y Farmacéullcas, Departamento de Química Inorgánica y Analítica. Universidad de Chile. Casilla 233,Santiago, Chile.