亚热带稻田土壤持续固碳机制研究进展

Progress on the mechanism of sustainable carbon sequestration in subtropical paddy soils

为准确评估亚热带稻田土壤的固碳特性及其有机碳的储量动态变化情况,进一步提升稻田土壤肥力,从亚热带稻田土壤碳库储量的时空分布与演变规律、稻田土壤有机碳的输入、微生物固碳的功能、有机碳矿化特性及其作用机制等方面进行了探讨。我国亚热带区稻田土壤有机碳储量与固碳效应明显高于旱地,其突出的碳固持能力主要是由于水稻光合碳的输入、土壤自养微生物固碳及淹水限制了微生物活性、抑制植物残体微生物分解过程,促进以植物残体直接积累。稻田土壤有机碳的矿化速率受碳氮磷计量、水肥管理措施以及温度等因素调控,从而影响着稻田土壤的固碳减排效率与潜力。本文提出“碳中和”背景下稻田土壤固碳减排的研究展望:基于亚热带稻田土壤对我国农田土壤碳固碳减排方面的重要性,提出了系统研究稻田生态系统中土壤有机碳累积和转化的作用机制,构建高精度的区域土壤有机碳库模拟模型及储量估算方法,以助力提升农田土壤肥力,加快我国农业双碳目标和农业绿色发展。

The subtropical paddy soils have the racteristics of long-term and sustainable carbon sequestration,and the dynamics of soil organic carbon(SOC)storage is of great significance for accurately assessing the“source-sink”function of regional carbon in China.This article discussed the temporal and spatial distribution and evolution of soil carbon storage in subtropical paddy soils,the input of soil organic carbon in paddy fields,the function of microbial carbon sequestration,the characteristics of organic carbon mineralization and its mechanism.The soil carbon sequestration and emission reduction in paddy soils under the background of"carbon neutrality"was prospected.The soil organic carbon storage and carbon sequestration of paddy soils in the subtropical region of China are obviously higher than those in other regions.Its outstanding carbon sequestration ability is mainly due to the input of photosynthetic carbon in rice,soil autotrophic microbial carbon sequestration and flooding,which limits microbial activity,inhibits the microbial decomposition process of plant residues,and promotes the direct accumulation of plant residues.The mineralization rate of soil organic carbon in paddy soils is regulated by factors including the stoichiometetry of carbon,nitrogen and phosphorus,management of water and fertilizer,and temperature,which affect the efficiency and potential of carbon sequestration and emission reduction in paddy soils.Based on the importance of subtropical paddy soils to soil carbon sequestration and carbon reduction of farmland soil in China,a systematic study on the mechanism of soil organic carbon accumulation and transformation in paddy ecosystems was proposed,and a high-precision regional soil organic carbon simulation model and methods for estimating soil organic carbon storage were constructed.It will help improve the soil fertility of farmland,accelerate the double-carbon goal of agriculture and promote the green development of agriculture in China.