Publication Date:
2016-08-31
Description:
Land cover changes have a great impact on nitrogen (N) and phosphorous (P) fluxes catchments. In this study we wanted to compare different land covers: deciduous (D), evergreen (E) (both native forests) and exotic Eucalyptus globulus plantation (EP), affected precipitation and stream discharge on N and P species concentrations and fluxes, under a low deposition climate in south central Chile. For this we collected bulk precipitation, throughfall and stream water samples after 41 rainfall events in E and EP, during the period June 2009 – March 2011 and 31 rainfall events in D, during the period October 2009 – March 2011. The highest canopy enrichment of N and P species for throughfall was observed in deciduous forest, while E. globulus showed the minimum enrichment. Total nitrogen (Total-N) discharge in EP was about 8.6 times higher than that of E and D catchments. Total-N annual retention was positive only in E and D catchments. However, EP catchment showed a net loss (-4.79 kg N ha -1 yr -1 ). The biggest difference was observed in nitrate stream concentrations, which showed low values for E (3.4 ± 1.3 µg L -1 ), while EP and D showed higher nitrate concentrations (84.9 ± 16.7 and 134.7 ± 36.7 µg L -1 , for EP and D respectively). Total phosphorous (Total-P) discharge flux was low in EP (0.4 kg P ha -1 yr -1 ), and negligible in E and D forests (〈0.1 kg P ha -1 yr -1 ). Total-P annual retention was near to 1.0 kg N ha -1 yr -1 (on E and D), while a net loss (-1.5 kg N ha -1 yr -1 ) was observed for EP. We attribute the observed differences in nutrient throughfall enrichment due to high multi-stratified canopies in the native forests. Both deciduous and evergreen native forest covered catchments showed the highest retention of total-N and total-P, in contrast to Eucalyptus covered plantation.
Print ISSN:
0885-6087
Electronic ISSN:
1099-1085
Topics:
Architecture, Civil Engineering, Surveying
,
Geography
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