ACCIóN DE MICROORGANISMOS EFICIENTES SOBRE LA ACTIVIDAD DE INTERCAMBIO CATIóNICO EN PLáNTULAS DE ACACIA (Acacia melanoxylon) PARA LA RECUPERACIóN DE UN SUELO DEL MUNICIPIO DE MONDO？EDO, CUNDINAMARCA

we determined the effect of efficient microorganisms (em) on the cation exchange capacity for soil recovery in the municipality of mondo？edo, cundinamarca. a greenhouse unit was installed in order to maintain stable conditions. after harvesting, sifted and homogenization of the soil sample, initial physical and chemical analyses were made. for the experimental units we used acacia melanoxylon seedlings from zabrinsky. a completely randomized design was done with eight treatments and three repetitions. for the maintenance and monitoring of the seedlings behaviour, a frequency of irrigation of three times per week was found. the application of the em was done during three months: in the first month, it was applied four times (once a week); during the second month, it was applied twice (biweekly), and during the third month there was only one application. additionally, every 15 days morphological analyses were made (number of leaves, branches and stem diameter). in the end, soil samples were taken from each plant pot. in the laboratory we analysed the cation exchange capacity, alkali ion exchange, saturation alkali, relations between elements and plant tissue. these were done using an atomic absorption spectrophotometer. statistical analyses consisted on multiple comparisons test and variance tests, in order to find whether or not treatments exhibited significant differences. in that way, the best alternative for improving environmental quality of eroded soils as the zabrinsky desert is the efficient microorganisms in 5% doses in irrigation water. additionally, the cation exchange capacity must be enhanced using organic fertilizers (compost, mulch and gallinaza) in one pound doses, and chemical fertilizers: electrolytic mn (0.0002 g), cu (0.0002 g), zn (0.0001 g), urfos 44 (166.66 g) and klip-boro (5 g).