成陆时间和沉积环境对宁绍平原水耕人为土形成的影响

为了解低平原地区水耕人为土分布的空间规律,以宁绍平原为例,探讨了成陆时间和沉积环境对水耕人为土性状与剖面发育的影响。田间调查表明,宁绍平原因成陆时间和成因的差异可被划分为近代浅海沉积区、低洼湖沼沉积区、古水陆相沉积区和古滨岸河湖沉积区等4种沉积环境,相应地分布的水耕人为土类型及性状有较大的差别。近代浅海沉积区主要分布普通简育水耕人为土,其性状变化与海涂围垦时间有关。低洼湖沼沉积区主要分布普通潜育水耕人为土或底潜简育水耕人为土,其性状的差异主要与距古湖沼中心距离有关。古水陆相沉积区主要分布普通铁聚水耕人为土,局部区域因上层滞水可形成铁聚潜育水耕人为土。古滨岸河湖沉积区的土壤类型主要为普通铁聚水耕人为土或普通简育水耕人为土。研究认为,通过沉积环境的识别有助于低平原地区水耕人为土类型的鉴定。

Terrestrial Formation Time and Sedimentary Environments: Effects on the Formation of Stagnic Anthrosols in Ningshao Plain

To understand the spatial distribution patterns of Stagnic Anthrosols in the low plain areas, the effects of terrestrial formation time and sedimentary environments on the characteristics and profile development of the soils was studied in the Ningshao plain as a case. The field survey showed that,based on the difference in terrestrial formation time and genesis of sediment, the Ningshao plain could be divided into four kinds of sedimentary environments, such as modern shallow marine sedimentary area, low-lying lake marshland area, paleo-continental facies sedimentary area and paleo-lake bank alluvium-lacustrine sedimentary area. Correspondingly, the types and properties of the Stagnic Anthrosols were also quite different. Types of the soils in modern shallow marine sedimentary area were mainly of typic haply-Stagnic Anthrosols, and their properties were related to the reclamation time of the tidal flat. Those in low-lying lake marshland area were mainly of typic gleyi-Stagnic Anthrosols and endogleyic haply-Stagnic Anthrosols, and their properties were mainly related to the distance from the center of the ancient lake and marshland. Typic Fe-accumuli-Stagnic Anthrosols was a main soil in the paleo-continental facies sedimentary area, Fe-accumulic gleyi-Stagnic Anthrosols were also distributed in some of the area because of the stagnant water in the upper part of soil profiles. Common types of the soils in paleo-lake bank alluvium-lacustrine sedimentary area were typic Fe-accumuli-Stagnic Anthrosols or/and typic hapli-Stagnic Anthrosols. The study indicated that identification of the sedimentary environment was helpful for identification of groups and subgroups of Stagnic Anthrosols in low plain areas.