PHOSPHORUS DYNAMICS OF PINYON-JUNIPER SOILS FOLLOWING SIMULATED BURNING

The objective of this study was to determine the effect of a simulated prescribed fire on P compounds in a Lithic Ustochrept soil supporting a pinyon-juniper woodland in Arizona. Soil, litter, and duff collected from beneath pinyon pine (Pinus edulis E. ) and Utah juniper left bracket Juniperus osteosperma (Torrey) Little right bracket and adjacent inter-spaces were used to reconstruct laboratory microcosms in clay pipes that were burned when soils were wet or dry. Soil temperatures were monitored continuously throughout the microcosms during burning. Total, bicarbonate-extractable (BEP), microbial, and organic P; phosphatase activity; and organic C were measured in the soil, litter, and duff before and immediately after burning and 45 and 90 d later. Soil texture, pH, and CaCO//3 equivalents were also determined on unburned soils.