| Nutrient input by rainfall is one of the main sources of nutrients for the natural forest ecosystems, and is important to forest growth. In addition, Rainfall nutrient input is an important component of the biogeochemical cycling in ecosystems. When rainfall through the canopy closure of the forest canopy, the canopy cover, most rainfall is trapped, some of which evaporate or be absorbed by the foliage, and anothers in throughfall stemflow form falls to the earth’s surface or penetrate into the soil. Rainfall is the main source of the forest nutrient inputs, rainfall through the forest canopy, happens elution eluviation or adsorption absorption.. After the nutrients of the throughfall directly down into the soil surface, thus plays an important role on forest soil nutrient availability.. Different time, environmental conditions and forest site types to rainfall in different nutrient absorption and utilization varies. A comparative study of Sitai and Chawan field’s atmospheric and throughfall rainfall, pH, EC and NH,+-N, NO3--N, SO42-, Cr, PO43--P, DOC, K+, Ca2+, Mg2+ to determine rainfall and rainfall characteristics and rain penetrating chemical characteristics of the subtropical forests. The results were as follows:(1) RainfallThe total rainfall from February 2012 to November 2013 was 3054.02 mm in Sitai, penetrating rainfall 2608.52 mm, penetrating rain rate was 85.41%, rainfall concentrated in summer. Chawan total rainfall in January 2012 to November 2013 period was 5077.44 mm, penetrating rain total was 4284.99 mm, the penetration rate was 84.39%. Rain penetrating rainfall and rainfall was Sitai <Chawan. Penetrating rainfall and atmospheric rainfall has great relevance,and related with the tree growth conditions, rainfall frequency and intensity.(2) pH and ECSitai and Chawan rainfall showed a neutral. pH relations in Sitai was rain rainfall region= penetrating rain, rainfall region> penetrating rain in Chawan. Rainfall pH values of the two regions was Chawan<Sitai, penetrating rain pH value was Chawan> Sitai. Rainfall pH value on the seasonal changes were manifested as low in summer and autumn.Shitai and Chawan rain forest atmosphere’s EC values relations was rainfall region<penetrating rain. Two regional rainfall and throughfall EC values was Chawan<Sitai. EC values of rainfall on seasonal changes, the performance was spring and summer low winter high.(3) Chemical compositionSize of the Shitai rainfall region various chemical elements was SO42->DOC>K++>Ca2+>C r>NO3--N>NH4+-N>Mg2+>PO43--P. Penetrating rain the various chemical elements was DOC> Mg2+>K+>PO43--P>NO3--N>Cl->Ca2+>SO42->NH4+-N.Sitai rainfall chemical elements content in addition to NH4+-N, others were penetrating rain> rainfall. Size of the Chawan rainfall reg ion various chemical elements was DOC>K+>SO42>Ca2+>Cl->NO3--N>Mg2+>NH4+-N>PO43--P. Penetrating rain chemical elements was Mg2+>K+>DOC>Cl->Ca2+>PO43--P>SO42->NO3--N>NH 4+-N. Chawan rainfall in the content of chemical elements were penetrating rain> rainfall. Ra infall in the two regions was Shita> Qimen. |
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