Soil Organic Carbon of Tea Plantation on Different Slope Positions in Low Mountains and Hills

The southern low mountains and hills have the largest tea plantation in China.Research on soil organic carbon of tea plantation on different slope positions was studied in low mountains and hills in the western Sichuan.The results indicated that the content of soil total organic carbon(TOC) followed the variety trend of middle slope upper slope lower slope,existing difference significantly(p0.05) between middle slope and lower slope.TOC of middle slope was lower than that of upper slope and lower slope 9.38%,13.95% respectively.The content of water-soluble organic carbon(WSOC) was significantly(p0.05) lowest in middle slope.Meanwhile,WSOC of middle slope was lower than that of upper slope and lower slope 33.33%,38.82% respectively.The variety trend of easily oxidized organic carbon(EOC) was the same as that of WSOC.EOC of middle slope was lower than that of upper slope and lower slope 12.25%,18.83% respectively.There were significant positive correlation between WSOC and TOC,TN(r=0.940,p0.01;r=0.966,p0.01),EOC and TOC,TN(r=0.995,p0.01;r=0.960,p0.01),WSOC and EOC(r=0.947,p0.01).Most of humus composed of loosely and tightly combined forms,following the order of middle slope upper slope lower slope.The ratio of loosely combined humus to tightly combined humus was higher than which of forest land on the same slope.The fulvic acid(FA) of loosely combined humus showed lowest on middle slope,but little higher than humin acid(HA) on other slopes.HA of tightly combined humus was higher on slope,while the maximum appeared on middle slope.The value of HA / FA of tightly combined humus was higher than that of loosely combined humus.