Litter fall production and nutrient dynamic of Cinnamomum camphora and Pinus massoniana mixed forests in subtropics China

This study selected typical needle and broadleaved subtropical forests( camphor and pinus massoniana mixed forests) as the research object; from 2009 to 2011 the litter fall was investigated monthly. The results showed that the annual litterfall production was( 4634. 723±337. 1427) kg / hm2,and foliage accounted for 71.78% branches( 26. 24%) litter debris( 8. 46%) fruits( 3. 23%). The total amount of litterfall had the obvious monthly dynamic. In November,its maximum was 1025. 6 kg / hm2; the minimum appears in February which was 138. 606 kg/hm2. There were significant differences of macroelemens and microelements in mixed forest. The order of the macroelemens was CNCaKSMgP, as the microelement was MnFeZnPbCdCuNiCo. The features of C / N was: the branch( 66. 96%) fruit( 63. 48%) leaf( 40. 62%). The content of litter nutrient directly determines the amount of nutrients return in forest. The amount of litter nutrients return was 80. 936 kg / hm2in Camphor and pinus massoniana mixed forest. The features of litter nutrients return of each element size sequence was: N Ca K S Mg P Mn Fe Zn Pb Cd Cu Ni Co. The characteristics of various components of the nutrients return was: leaf( 67. 469 kg / hm2) branch( 14.928kg/hm2) fruit( 2.361 kg/hm2). The amount of N return in mixed forest was 40. 964 kg/hm2. Among this,the return amount of N in leaf had a value of 34. 877 kg / hm2.