Land use affects soil organic carbon of paddy soils: empirical evidence from 6280 years BP to present
Land use affects soil organic carbon of paddy soils: empirical evidence from 6280 years BP to present
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DOI：
10.1007/s11368-015-1297-x
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发表时间：
2016-03
影响因子：
3.6
通讯作者：
Jin Zhang;Minyan Wang;Shengchun Wu;K. Müller;Yucheng Cao;P. Liang;Z. Cao;A. Leung;P. Christie-P.-Ch
中科院分区：
文献类型：
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作者：
Jin Zhang;Minyan Wang;Shengchun Wu;K. Müller;Yucheng Cao;P. Liang;Z. Cao;A. Leung;P. Christie-P.-Ch
目的中国的水稻栽培已有 7000 年历史。关于这一历史时期稻田土壤有机碳（SOC）含量变化的经验证据很少。因此，本研究开展了田间研究，探讨淹水栽培对稻田SOC积累和保存的影响。 材料与方法通过在中国东部长江三角洲地区发掘出两处埋藏古稻剖面（距今6280年，命名为P-01和P-03），揭示从史前时期至今，在人为土地利用和环境变化下，稻田演化过程中土壤中SOC含量的变化。确定了不同时间点的 SOC 浓度、总氮浓度和稳定碳同位素比的趋势。结果与讨论 P-01 水稻土层 100-174 cm 深度处发现有机碳积累。该遗址在距今约 6280 年前就进行了水下水稻种植。史前水稻表土100~130 cm深度的平均SOC浓度为1.27%，是P-03附近103~130 cm深度未耕地土壤有机碳浓度的7倍。这意味着在此期间，水稻土在淹没管理下经历了大量的二氧化碳封存。到距今约 3320 年，有机碳含量减半，可能是由于海平面上升导致海洋淹没。截至2003年，当前水稻土各层的SOC含量均有所增加，特别是表层，表明水稻连续种植。然而，由于快速的城市化和工业化，中国东部地区的水稻种植逐渐停止，导致 SOC 储量在 6 年时间里（2003 年至 2009 年）损失了约 10%。 P-01（r= 0.71，p< 0.01）和P-03（r= 0.72，p< 0.01）稻田土壤层中的SOC与水稻植硅体含量之间存在显着相关性，表明植硅体吸留的有机碳可以作为生物标志物来确定过去稻田演化中SOC的发展情况6000 年。结论沉水水稻种植导致稻田中 SOC 显着积累。植硅体包埋有机碳可作为监测稻田土壤有机碳含量变化的生物标志物。
PurposeSubmerged rice cultivation has been practiced in China for 7000 years. Empirical evidence on changes of soil organic carbon (SOC) contents in paddy soils over this historical time period is scarce. Therefore, a field study was conducted to investigate the effect of submerged rice cultivation on the accumulation and preservation of SOC in paddies.Materials and methodsTwo buried ancient paddy profiles (6280 years BP, named P-01 and P-03) in the Yangtze Delta of eastern China were excavated to illustrate the development of SOC contents in soils during the evolution of paddies under anthropogenic land use and environmental changes from the prehistoric period to the present time. Trends in SOC concentrations, total nitrogen concentrations, and stable carbon isotope ratio were identified for different points in time.Results and discussionAccumulation of organic carbon was found in the paddy soil layers of P-01 at 100–174 cm depth. This site was taken under submerged rice cultivation in about 6280 years BP. The average SOC concentration in the prehistoric paddy topsoil in 100–130 cm depth was 1.27 %, which is seven times higher than that in the adjacent uncultivated land at 103–130 cm depth of P-03. This implies that the paddy soil has experienced substantial CO2sequestration under submerged management during that time. By about 3320 years BP, organic carbon contents were halved, potentially due to marine inundation by sea level rise. Up to the year 2003, the SOC contents in all horizons in the present time paddy soil have increased, especially in the surface layer, indicative of continuous rice cultivation. However, due to rapid urbanization and industrialization, the cultivation of paddies in eastern China has gradually been discontinued leading to the loss of SOC stocks of approximately 10 % in a 6-year interval (from 2003 to 2009). A significant relationship between SOC and rice phytolith contents was found in the paddy soil horizons of P-01 (r= 0.71,p< 0.01) and P-03 (r= 0.72,p< 0.01), suggesting that phytolith-occluded organic carbon could be used as a biomarker to ascertain the development of SOC in the evolution of rice paddies over the past 6000 years.ConclusionsSubmerged rice cultivation led to a noticeable accumulation of SOC in paddies. Phytolith-occluded organic carbon could be used as a biomarker to monitor changes of OC contents in paddy soils.