三峡库区典型流域退耕地植物种类及凋落物对土壤有机碳固定的影响

Effects of plant species and litter on soil organic carbon sequestration in converted croplands in a typical watershed in Three Gorges Reservoir area of China

研究三峡库区典型流域退耕地植物种类和凋落物对土壤有机碳(SOC)固定和迁移的影响。2008年设计C3植物处理(A1)、C4植物香附子无凋落物处理(B0)和双倍凋落物处理(B2)裂区试验,2010年分层采集土壤和植物样品,测定SOC碳密度和稳定性碳同位素δ13C值的变化。结果表明:三峡库区典型流域退耕地土壤SOC密度由于土地利用的变化均发生了变化,退耕2年后,A1区内0～30cm层内SOC量持续增加,平均增加了58.4g·m-2(1.1%);C4处理的无凋落物区B0,SOC密度增加最为显著,为303g·m-2(4.9%),但双倍凋落物区B2,SOC密度降低了79g·m-2(1.1%)。凋落物对SOC密度影响显著(P<0.05)。

In order to understand the effects of plant species and litter on the soil organic carbon sequestration and translocation in converted croplands in a typical watershed in Three Georges Reservoir area,a field experiment was conducted.Three treatments including C3 plant（A1） and C4 plant Rhizoma cyperi with litter removal（B0） versus with double litter input（B2） were installed in 2008,and soil and plant samples were collected in 2010,with the organic carbon concentration and δ13C value in soil profiles measured.A changed organic carbon concentration in the soil profiles was observed due to the land use change.After 2 years conversion,the organic carbon concentration in 0-30 cm soil layer in A1 had an increase of 58.4 g C·m-2（1.1%）,that in B0 had a distinct increase of 303.3 g C·m-2（4.9%）,while that in B2 was decreased by 79 g C·m-2（1.1%）.Litter input had significant effects on the soil organic carbon density（P0.05）.