地形部位对亚热带低丘梯田土壤性态与类型的影响

Effects of Topographic Position on Soil Properties and Types of Terraced Fields in Subtropical Low Hills

【目的】为了解地形对亚热带丘陵地区稻田土壤发生与演变的影响。【方法】在浙江省衢州市和杭州市分别选择了由第四纪红土和凝灰岩风化物等2类母质发育的地形系列梯田,比较分析了岗背、高坡、缓坡和坡麓等不同地形部位梯田土壤剖面发生学性状及土壤类型的差异。【结果】结果表明,由岗背经高坡、缓坡至坡麓,土壤受耕作熟化影响(包括颜色变化、酸度下降)的程度逐渐加深,土体厚度、氧化还原层厚度和铁锰新生体数量、剖面中黏粒和氧化铁含量的垂直分异呈增加的趋势,同时表土有机碳、全氮、全磷、有效磷的积累也呈现增加趋势。调查表明,2类母质发育的土壤中位于坡麓地带的梯田土壤剖面氧化铁垂直迁移显著,土壤类型属铁聚水耕人为土;岗背和高坡部分的梯田土壤剖面发育相对较弱,形成的为简育水耕人为土;缓坡地梯田中可发生铁的渗移,形成的土壤或为铁渗水耕人为土或为简育水耕人为土。【结论】研究认为,地形部分可通过改变土壤剖面中水分状况和运移影响亚热带低丘陵地区水耕人为土的发育。

[Objective] In order to understand the influence of topography on the occurrence and evolution of Stagnic Anthrosols in subtropical hilly area, [Method] the topographic series of terraces formed from quaternary red clay and tuff rock were selected in Quzhou and Hangzhou, Zhejiang Province. The genetic characteristics and soil types of terraced fields were compared in different topographical positions such as back of hill, high slope, gentle slope and foot of the slope. [Result] The results showed that the soil developing degrees were gradually deepened by cultivation and ripening(including color change and acidity decrease) from the back of the hill to the foot of the slope. The vertical differentiation in soil thickness, redox layer thickness and the number of Fe-Mn new-growth, clay and iron oxide content of the profile increased, and the accumulations of organic matter, total nitrogen, total phosphorus and available phosphorus also increased. The investigation showed that the vertical migration of iron oxide in the terrace soil profile at the foot of the slope was significant,and the soil type in the position belonged to the Fe-accumuliStagnic Anthrosols. The development of soil profiles in the back of the hill and the high slope was relatively weak, and the soil type was the Hapli-Stagnic Anthrosols. The iron infiltration could occur in the terrace on the gentle slope, and the soil type was classified as Fe-leached Stagnic Anthrosols or the Hapli-Stagnic Anthrosols. [Conclusion] Topography could affect the development of Stagnic Anthrosols in subtropical low hill area by changing the status and migration of moisture in soil profile.