Some factors affecting the mineralization of organic matter in volcanic ash soils

THESE HYPOTHESES INCLUDE A LACK OF AVAILABLE CARBON FOR ENERGY AND MICROBIAL GROWTH, AND LOW AVAILABLE PHOSPHORUS AND INORGANIC NITROGEN. VARIOUS EXPERIMENTS TESTING THESE HYPOTHESES WERE CONDUCTED USING THE SURFACE HORIZONS OF FOUR VOLCANIC ASH SOILS FROM COLOMBIA. SOME OF THE RESULTS WERE THAT 1) THE ADDITION OF DIFFERENT RATES OF READILY AVAILABLE CARDON DID NOT INCREASE SOIL CARBON MINERALIZATION AND DECREASED THE INORGANIC NITROGEN CONTENT OF THE SOILS AFTER 30 DAYS OF AEROBIC INCUBATION; 2) LOW PHOSPHORUS AVAILABILITY IS A FACTOR IN LOW ORGANIC MATTER MINERALIZATION IN THE SOILS; 3) 20, 80, AND 200 PPM NITROGEN INCREASED NET NITROGEN MINERALIZATION; 4) A LACK OF AVAILABLE CARBON DID NOT CONTRIBUTE TO LOW NITROGEN MINERALIZATION; 5) CALCIUM CHLORIDE INCREASED THE SOIL"S INORGANIC CONTENT WITHOUT INCREASING MICROBIAL RESPIRATION AND THIS EFFECT WAS ACCOMPANIED BY A SEVERE DROP IN SOIL PH.