EFFECTS OF ARTIFICIAL NITROGEN AND PHOSPHORUS DEPOSITIONs ON SOIL RESPIRATION IN TWO PLANTATIONS IN SOUTHERN CHINA

Abstract

CAO YS, LIN YB, RAO XQ & FU SL. 2011. Effects of artificial nitrogen and phosphorus depositions on soil respiration in two plantations in southern China. In the present study, atmospheric nitrogen (N) and phosphorus (P) depositions were simulated with NH₄NO₃ and KH₂PO₄ solutions respectively to investigate
the effects of N and P depositions on soil respiration in two plantations in southern China. The annual soil respiration rate under the control plot was 3190 ± 39.4 g CO₂ m^-2 and in the Acacia mangium and Eucalyptus urophylla plantations, the rate was 5180 ± 72.2 g CO₂ m^-2. Results of the field experiment showed that both N and P treatments promoted soil respiration rates under A. mangium but significantly decreased the soil respiration under E. urophylla. The lower level (5 ppm) P treatment significantly enhanced soil respiration rates in A. mangium and E. urophylla plantations. However, with the increase in P concentration, the soil respiration rates decreased under A. mangium but increased under E. urophylla. Soil respiration rates exhibited significant fluctuation and approached to nearly equal values at the end of the experiment.