四川盆地水稻土有机碳与全氮的时空变异及影响因素研究

Spatial-temporal Variability of Soil Organic Carbon and Total Nitrogen in Paddy Soils in Sichuan Basin

利用全国第二次土壤普查数据与2008年采样数据对四川盆地水稻土有机碳和全氮的含量水平变化进行了研究。结果表明:研究区1982年和2008年3种水稻土亚类有机碳含量均呈现潜育型水稻土显著高于淹育型和潴育型水稻土。研究区1982年3种水稻土亚类全氮含量呈现潜育型水稻土显著高于淹育型水稻土,2008年则为潜育型水稻土显著高于淹育型和潴育型水稻土。26年间水稻土有机碳与全氮含量均增长明显,且淹育型与潜育型两种水稻土的增长幅度高于潴育型水稻土。1982年至2008年,平坝、冲沟和坡脚稻田中有机碳及全氮含量增长明显,且大致呈从平坝、冲沟到坡中上部递减;冲积物和泥岩发育的水稻土有机碳及全氮因易于积累而含量更高;质地黏重的土壤有机碳与全氮的含量较高,同时也比质地偏轻的土壤更利于碳、氮的积累;冬水田与稻–油轮作的农田土壤有机碳与全氮的含量与增长幅度显著高于稻–麦轮作田。

Changes of the soil organic carbon （SOC） and soil total nitrogen （STN） concentrations in paddy soil of Sichuan Basin were studied using the data of the Second China National Soil Survey and the data of soil samples collected in 2008. The results showed that the SOC concentrations in gley paddy soils were obviously higher than these in both the submerged paddy soils and the waterlogged paddy soils in 1982 and 2008. However, the STN concentrations in the three types of paddy soils showed different trends. The STN concentrations in gley paddy soils in 1982 were higher than these in submerged paddy soils and higher than these in the other two soils in 2008. The concentrations of STN and SOC increased sharply in the past 26 years and the increasing amplitudes of STN and SOM in the submerged paddy soils and gley paddy soils were higher than these in the waterlogged paddy soils. From 1982 to 2008, the SOC and STN concentrations in plain area, gully and toe of slope increased obviously and the increasing amplitudes followed the order： plain area 〉 upper part of slope. The concentrations of SOM and STN were higher in the paddy soils generated from alluvium and mudstone due to the easier accumulation of SOC and STN in the soils. The easier accumulation of SOM and STN in weight loam soils led to the higher concentrations the SOC and STN in the soils compared with light loam soils. The increasing amplitudes of SOC and STN in the soils of winter paddy yield and rice-rape rotation were obviously higher than these in the soils of rice-wheat rotation.