CAJ | 학술논문

时间序列方法是研究土壤发生特性演变的重要途径,而比较土壤变化的重要前提之一是序列中的土壤具有相同的起源,即具有母质的相对均一性.本研究根据史料记载中浙江慈溪海塘修筑年代估计出水稻土的耕作年龄,选择了植稻年龄约为50、300、500、700、1 000 a以及一个未垦滩涂剖面组成的一个时间序列作为研究对象.利用各种土壤属性参数对该时间序列的母质不连续性(或母质均一性)以及水稻土相对年龄进行了判定和验证.结果表明,时间序列的6个剖面虽然具有微小的差异,但其剖面内与剖面间母质来源相同.在水稻土母质不连续性判定中,去除黏粒的粉粒与粉粒中稳定元素Ti/Zr比值具有较好的指示作用.相对易变的土壤属性参数如碳酸钙、磁化率以及游离铁的剖面分异程度在水稻土相对年龄的判定中具有较好的指示作用.综合这些参数在时间序列中的演化趋势,发现500 a剖面与整个序列的变化趋势不相符合,可能是利用历史的差异所致,在相关的性质演变研究中应该从序列中剔除.
시간서렬방법시연구토양발생특성연변적중요도경,이비교토양변화적중요전제지일시서렬중적토양구유상동적기원,즉구유모질적상대균일성.본연구근거사료기재중절강자계해당수축년대고계출수도토적경작년령,선택료식도년령약위50、300、500、700、1 000 a이급일개미은탄도부면조성적일개시간서렬작위연구대상.이용각충토양속성삼수대해시간서렬적모질불련속성(혹모질균일성)이급수도토상대년령진행료판정화험증.결과표명,시간서렬적6개부면수연구유미소적차이,단기부면내여부면간모질래원상동.재수도토모질불련속성판정중,거제점립적분립여분립중은정원소Ti/Zr비치구유교호적지시작용.상대역변적토양속성삼수여탄산개、자화솔이급유리철적부면분이정도재수도토상대년령적판정중구유교호적지시작용.종합저사삼수재시간서렬중적연화추세,발현500 a부면여정개서렬적변화추세불상부합,가능시이용역사적차이소치,재상관적성질연변연구중응해종서렬중척제.
Soil chronosequence is a valuable means in investigating rates and directions of pedogenic evolution. A soil chronosequence consisting of one tract of mudflat and five paddy soils of different rice cultivation ages were selected for this study. Ages of the paddy fields were estimated according to the literature available indicating the time when the polder was built up to reclaim the mudflat into paddy fields. The objectives of this study were to evaluate lithologic discontinuity (LDs) of the parent material in the inter-and intra-profiles of the chronosequence, and to verify relative ages of the fields by making use of various soil attribute parameters. Results show that low variation coefficient was associated with clay-free silt and Ti/Zr ratio of the silt fraction between horizons, suggesting no LDs in the studied profiles, that is to say, the profiles of the chronosequence have developed from a relatively homogeneous parent material. The clay-free silt and Ti/Zr ratio of the silt fraction are the most useful parameters in identifying LDs in this study. In order to establish a well-dated chronosequence, CaCO_(3) content, magnetic susceptibility and differentiation degree of free iron oxide in the profiles were used to assess soil relative ages and they were shown as good indicators of soil age and development. However, these parameters in the 500a soil profile have an odd tendency along the sequence, so it should be excluded from the chronosequence when a reliable comparison of soil changes is desired.