[Quantifying rice (Oryza sativa L.) photo-assimilated carbon input into soil organic carbon pools following continuous 14C labeling].
The microcosm experiment was carried out to quantify the input and distribution of photo-assimilated C into soil C pools by using a 14C continuous labeling technique. Destructive samplings of rice (Oryza sativa) were conducted after labeling for 80 days. The allocation of 14C-labeled photosynthates in plants and soil C pools such as dissolved organic C (DOC) and microbial biomass C (MBC) in rice-planted soil were examined over the 14C labeling span. The amounts of rice shoot and root biomass C was ranged from 1.86 to 5.60 g x pot(-1), 0.46 to 0.78 g x pot(-1) in different tested paddy soils after labeling for 80 days, respectively. The amount of 14C in the soil organic C (14C-SOC) was also dependent on the soils, ranged from 114.3 to 348.2 mg x kg(-1), accounting for 5.09% to 6.62% of the rice biomass 14C, respectively. The amounts of 14C in the dissolved organic C (14C-DOC) and in the microbial biomass C(14C-MBC), as proportions of 14C-SOC, were 2.21%-3.54% and 9.72% -17.2%, respectively. The 14C-DOC, 14C-MBC, and 14C-SOC as proportions of total DOC, MBC, and SOC, respectively, were 6.72% -14.64%, 1.70% -7.67%, and 0.73% -1.99%, respectively. Moreover, the distribution and transformation of root-derived C had a greater influence on the dynamics of DOC and MBC than on the dynamics of SOC. Further studies are required to ascertain the functional significance of soil microorganisms (such as C-sequestering bacteria and photosynthetic bacteria) in the paddy system.
Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China. nsa0804@163.com
San-An
SA
Nie
Ping
P
Zhou
Ti-Da
TD
Ge
Cheng-Li
CL
Tong
He-Ai
HA
Xiao
Jin-Shui
JS
Wu
Yang-Zhu
YZ
Zhang
D002244:Carbon / Q000032:analysis* / Q000378:metabolism; D002250:Carbon Radioisotopes / Q000032:analysis*; D009930:Organic Chemicals / Q000032:analysis; D012275:Oryza / Q000378:metabolism / Q000502:physiology*; D010788:Photosynthesis / Q000502:physiology*; D012987:Soil / Q000737:chemistry*
D002250:Carbon Radioisotopes; D009930:Organic Chemicals; D012987:Soil; D002244:Carbon