水耕条件下两类富钙母岩发育土壤的系统分类归属及成因探讨  

Taxonomy and Genesis of Soils Derived from Two Types of Calcium-rich Rocks Under Rice-planting Conditions

作　　者：李松 慈恩[1] 连茂山 曾蔓漫 胡瑾 LI Song;CI En;LIAN Maoshan;ZENG Manman;HU Jin(College of Resources and Environment,Southwest University,Chongqing 400715,China)

机构地区：[1]西南大学资源环境学院,重庆400715

出　　处：《土壤学报》2022年第3期678-687,共10页Acta Pedologica Sinica

基　　金：国家自然科学基金项目(41977002);国家科技基础性工作专项(2014FY110200);中央高校基本科研业务费专项资金项目(XDJK2020B069)资助。

摘　　要：在重庆境内,遂宁组(J_(3)s)钙质泥岩发育水耕人为土的剖面分异多不明显,而石灰岩发育水耕人为土则不尽如此,其原因尚不明确。为此,以上述两类母岩在不同坡位发育的水耕人为土为研究对象,分析水耕条件下钙质泥岩和石灰岩发育土壤的发生特征及系统分类归属,并以有机碳矿化特性为切入点,探讨其成因。结果表明,从中坡至坡麓,钙质泥岩发育的水耕人为土(CS)结构面上均仅有少量锈斑且游离铁的垂直分异不明显,而石灰岩发育的水耕人为土(LS)结构面上有少量至多量锈斑且在不同坡位的分布状况不同,特别是下坡呈酸性的土体中游离铁的下层聚集显著,表明两类母岩发育水耕人为土铁的剖面迁移特征有明显差异。CS的有机碳累积矿化量(C_(15))显著低于同坡位的LS(P<0.05),较低量的易矿化有机碳使得CS土体中高价铁难以发生还原,铁的剖面迁移不明显,导致不同坡位的CS典型个体均被归为简育水耕人为土;从中坡至坡麓,LS的C_(15)逐级增高,且坡麓的C_(15)显著高于其他坡位(P<0.05),加之受与坡位关联的土壤水分状况影响,其典型个体依次被归为“简育”“铁聚”和“潜育”水耕人为土土类。易矿化有机碳含量可能是决定坡位能否引起富钙母岩发育的水耕人为土产生类型分异的重要因素。【Objective】In Chongqing,changes in soil morphological characteristics of Stagnic Anthrosols derived from calcareous mudstone are not obvious from top to bottom of the soil profile in most cases.However,this phenomenon is not always so for Stagnic Anthrosols derived from limestone.Given that the reason for this difference is not clear,there is a need for further studies in this area.Therefore,this paper discusses the occurrence and evolution characteristics;types and causes of calcareous mudstone and limestone soils under rice-planting conditions,to improve the accuracy of the systematic classification and spatial distribution prediction.【Method】Field soil surveys were conducted to identify six Stagnic Anthrosols profiles of different slope positions(mesoslope,baseslope and footslope)on limestone and calcareous mudstones and to obtain soil-forming conditions and soil morphological characteristics of the profiles.Soil samples were collected from the profiles by horizon for analysis of physical and chemical properties.According to the“Keys to Chinese Soil Taxonomy(3rd ed.)”,diagnostic horizons and diagnostic characteristics for the tested soils were determined,and the soils were attributed and named in Chinese Soil Taxonomy level by level.The soil genesis of the tested soils is discussed based on the characteristics of organic carbon mineralization.【Result】From the mesoslope to footslope,there was very few rust mottles on the structural plane of Stagnic Anthrosols derived from calcareous mudstone(CS),and the vertical differentiation of free iron was not obvious.However,there was very few to many rust mottles on the structural plane of Stagnic Anthrosols derived from limestone(LS),and the distribution was different in different slope positions.Especially in the acid soil of the baseslope,the lower layer of free iron accumulated significantly.This showed that there were differences in iron migration characteristics between the Stagnic Anthrosols derived from the different types of parent rocks.The accu

关 键 词：土壤发生 系统分类 水耕人为土 有机碳矿化 富钙母岩 

分 类 号：S155.3[农业科学—土壤学]