tailieunhanh - Báo cáo lâm nghiệp: "Precipitation partitioning and related nutrient fluxes in a subtropical forest in Okinawa, Japan"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài:"Precipitation partitioning and related nutrient fluxes in a subtropical forest in Okinawa, Japan" | Ann. For. Sci. 62 2005 245-252 245 INRA EDP Sciences 2005 DOI forest 2005016 Original article Precipitation partitioning and related nutrient fluxes in a subtropical forest in Okinawa Japan Xiaoniu XUa b c Qin WANGa b Eiji HIRATAb a Department of Forestry Anhui Agricultural University Hefei Anhui 230036 . China b Faculty of Agriculture University of the Ryukyus Nishihara Okinawa 903-0213 Japan c Present address Field Science Center for Northern Biosphere Hokkaido University Nayoro Hokkaido 096-0071 Japan Received 15 April 2004 accepted 31 August 2004 Abstract - Precipitation partitioning into throughfall and stemflow and related hydrochemical fluxes were examined during a 3 y period from January 1998 to December 2000 in a subtropical evergreen broad-leaved forest on Okinawa Island Japan. Monthly water samples were collected to determine the concentrations and associated fluxes of bioelements. The mean annual precipitation during the study period was 3325 mm. Typhoons played a central role in the hydrology of the study forest with 11 typhoons contributing of the total rainfall over the 3 y period. Throughfall and stemflow contributed and of the annual rainfall respectively implying a rainfall interception of . The very high fraction of stemflow could be due to the crown morphology of the dominant species Castanopsis sieboldii that has inclined branches and concave shaped leaves. Mean pH in the precipitation was and decreased significantly as the water passed through the canopy. Concentrations of total N DOC K Na Ca and Mg showed a clear pattern of enrichment in both throughfall and stemflow compared to rainfall. The proximity to the Pacific Ocean strongly influenced the nutrient fluxes via rainfall at our site as illustrated by the extremely high Na fluxes via rainfall 213 kg Na ha-1 y-1 and throughfall plus stemflow 291 kg Na ha-1 y-1 . The mean annual nutrient inputs in kg ha-1 were total N 43 P K 76 Ca49 Mg 30 Na 291 Al