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

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。

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

Changes of the SOC and STN concentrations in paddy soil of Sichuan Basin were studied through the data of the Second China National Soil Survey and the sampled data collected in 2008. The results showed that the SOC concentrations in gley paddy soil was obviously higher than that in both the submerged paddy soil and the waterlogged paddy soil in 1982 and 2008. However, the STN concentration of the three soils presents a different trend. The STN concentration in gley paddy soil in 1982 was higher than that in submerged paddy soil and higher than that 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 submerged paddy soil and gley paddy soil were higher. From 1982 to 2008, the SOC and STN concentrations in plain area, gully and toe of slope increased obviously and the amplitudes showed a decreasing trend from plain area and upper part of slope; the concentrations were higher in the paddy soils generated from alluvium and mudstone for the reason that the SOC and STN were more easily to accumulate; the concentrations were higher in weight loam for the reason that the SOC and STN were more easily to accumulate than light loam; the increase amplitudes of SOC and STN in winter paddy yield and rice-rape rotation soils were obviously higher than that of rice-wheat rotation.