Lin Sen, Xiao Mou-Liang, Jiang Jia-Bin, Wei Liang, Li Ke-Lin, Liu Shou-Long, Zhu Zhen-Ke, Ge Ti-da, Wu Jin-Shui
School of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China.
Key Laboratory of Subtropical Agro-Ecological Processes, Institute of Subtropical Agro-Ecology, Chinese Academy of Sciences, Changsha 410125, China.
Huan Jing Ke Xue. 2021 Feb 8;42(2):988-995. doi: 10.13227/j.hjkx.202007177.
The rhizosphere priming effect (RPE) caused by carbon inputs from crop rhizodeposits plays a key role in regulating the carbon emission flux and carbon balance of farmland soils. Due to frequent alternations between dry and wet conditions, CO and CH emissions and the RPE in paddy field ecosystems are significantly different to those of other ecosystems. Therefore, it is of great significance to determine the direction and intensity of the rice RPE under alternations of dry and wet to limit greenhouse gas emissions. In this study, using a C-CO continuous labeling method combined with a pot-based experiment, the response of rice growth and the RPE under alternating dry and wet and continuous flooding conditions was examined. The results showed that, compared with the continuous flooding treatment, the alternating dry and wet treatments significantly increased aboveground and root biomass and the root-to-root ratio, and also increased soil microbial biomass. Under continuous flooding conditions, fluxes of CO and CH increased with rice growth from 10.2 μg·(kg·h) and 2.8 μg·(kg·h) (63 d) to 16.0 μg·(kg·h) and 3.2 μg·(kg·h) (75 d), respectively. During the 12-day drying process, the emissions of CO and CH derived from rhizosphere deposited C decreased by 57.5% and 88.1%. Under continuous flooding conditions, the RPE for CO and CH were positive and increased with the growth of rice. Under the alternating dry and wet treatment, after 12 days of drying, the RPE for CO and CH was reduced from 0.29 mg·(kg·h) and 12.3 μg·(kg·h) (63 d) to -0.39 mg·(kg·h) and 0.07 μg·(kg·h) (75 d). Thus, alternating wet and dry treatment can effectively promote rice growth and reduce the cumulative emissions of CH. Therefore, adopting appropriate field water management is of great significance for increasing rice yields and mitigating greenhouse gas emissions.
由作物根际沉积物输入的碳所引起的根际激发效应（RPE）在调节农田土壤碳排放通量和碳平衡方面起着关键作用。由于干湿条件频繁交替，稻田生态系统中的CO和CH排放以及根际激发效应与其他生态系统显著不同。因此，确定干湿交替条件下水稻根际激发效应的方向和强度对于限制温室气体排放具有重要意义。在本研究中，采用C-CO连续标记法并结合盆栽试验，研究了干湿交替和持续淹水条件下水稻生长及根际激发效应的响应。结果表明，与持续淹水处理相比，干湿交替处理显著增加了地上部和根系生物量以及根冠比，还增加了土壤微生物生物量。在持续淹水条件下，CO和CH通量随水稻生长分别从10.2 μg·(kg·h)和2.8 μg·(kg·h)（63天）增加到16.0 μg·(kg·h)和3.2 μg·(kg·h)（75天）。在为期12天的干燥过程中，根际沉积碳产生的CO和CH排放分别减少了57.5%和88.1%。在持续淹水条件下，CO和CH的根际激发效应为正，且随水稻生长而增加。在干湿交替处理下，干燥12天后，CO和CH的根际激发效应从0.29 mg·(kg·h)和12.3 μg·(kg·h)（63天）降至-0.39 mg·(kg·h)和0.07 μg·(kg·h)（75天）。因此，干湿交替处理可有效促进水稻生长并减少CH的累积排放。所以，采用适当的田间水分管理对于提高水稻产量和减轻温室气体排放具有重要意义。
