Resumen

SIVILA DE CARY, Ruth  y  ANGULO, Wilma. Fallow effect on soil microbial population (Patarani - Bolivian central Altiplano). Ecología en Bolivia [online]. 2006, vol.41, n.3, pp.103-115. ISSN 1605-2528.

In the central high plateau of Bolivia (called central Altiplano) (3,800-4,000 m asl.) and the Patarani’s community where a long fallow is applied after crop during three years, we studied the microbial population of fallow soils during three years. In this work we analysed soils in plots with different fallow stages: initial (1-4 years), intermediate (5-9 years) and late (10-20 years). The microbial analysis were the microbial biomass N (fumigation -extraction method) and counts on solid culture media of living forms of bacteria, fungi, actynomycetes, acydophilles, and sporulates, and in liquid media by the Most Probable Number (NMP) method counts of total microbial population, amylolytics, and proteolytics. The analyses were also performed for arbuscular mycorrhiza spores, chemical variables of the soil, and microbial activity expressed as amylolytic and proteolytic activities determined by the method of the index of mean dilution. The results on the microbiota show clear tendency to increase with fallow years, in the following direction: early stage < intermediate stage < final stage. Numbers of acydophilles and amylolytics decreased in the opposite sense: early stage > intermediate stage > final stage. Soil analysis show that almost all the values increase in the final stage of the fallow, with high values found for C%, N total and CIC (exchangeable cations). The total of arbuscular mycorrhiza spores is the parameter that best reflects the fallow duration (R≤ = 0.83).

Palabras clave : Soil microorganisms; long fallow; Bolivian Altiplano; mycorrhizae.

        · resumen en Español     · texto en Español     · Español ( pdf )