Dynamic Research Of Soil Carbon And Nitrogen Under Evergreen Broad-leaved Forest And Chinese Fir Plantation In Maofeng Mountain, Guangzhou

Forest soil is one of the important pools for storing carbon and n itrogen. The variation ofcarbon and nitrogen in soil is one of the signi ica t ecological process on the earth. Evergreenbroad-leaved forest of Maofeng Moutain is natural secondary forest ecosystem which coveredlarge area and complete structure in Guangzhou. Forest ecosystem positioning method andcontrast method were used to study soil carbon, nitrogen and soil microorganism underevergreen broad-leaved forest and Chinese Fir plantation. Study period was set fromMarch,2011to February,2012.Variation of soil carbon, nitrogen and soil microorganism in0-10cm，10-30cm，30-50cm，50-70cm，70-90cm were studied and results were belowed:(1)Soil organic carbon(SOC)content of evergreen broad-leaved forest(ebf) and ChineseFir plantation(cfp) were decreased with soil depth, SOC content of ebf and cfp were highest indepth5cm.(2)Soil total nitrogen (TN) and organic nitrogen (TON) content of ebf and cfp weredecreased with soil depth, TON content of ebf and cfp were highest in depth5cm.(3)Content of TOC in cfp was highest in November (1.93%), lowest in March(0.98%);content of TOC in ebf was highest in March(1.38%), lowest in January(1.02%). Content ofinorganic carbon in cfp was highest in March(1.25%), lowest in January (0.02%); content ofTOC in ebf was highest in April(0.99%), lowest in February(0.02%).(4)Content of TN in cfp was highest in April (0.12%), lowest in July, August andSeptember(0.08%); content of TON in cfb was highest in February(864mg/kg), lowest inOctober(740mg/kg). Content of inorganic carbon in ebf was highest in December(0.14%),lowest in September (0.09%); content of TON in ebf was highest in December(1013mg/kg),lowest in September(707mg/kg).(5)From March to February in next year, content of organic carbon density(SCD)in ebfwas highest in November(44.2(t/hm~2)),lowest in March(22.1(t/hm~2)),content of SCD in cfp was highest in December(3.2(t/hm~2)),lowest in August and January(2.2(t/hm~2)).Content ofnitrogen density in ebf was highest in April(2.7(t/hm~2)), Content of nitrogen density in cfp washighest in December(3.2(t/hm~2))(6)Ammonifying bacteria, Nitrifying bacteria, Nitrite bacteria and Denitrifying bacteriain ebf and cfp were not decreased with soil depth.(7)Soil organic nitrogen was positive correlated withorganic carbon. There was negativecorrelation ship between soil organic nitrogen and soil moisture. Content of Nitrifying bacteriawas negative correlated with soil organic nitrogen.