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为研究不同土地利用方式对土壤团粒的影响,探索土壤质量、结构的定量化描述,采用湿筛法对重庆市荣昌县吴家镇的旱地(玉米地),水田(望天田),撂荒地(旱地撂荒8年以上,常年为白茅草覆盖)和人工林(柏树,种植年限12年)4种利用方式下土壤的团聚体含量进行了测定并对其分形特征进行了研究。结果表明:土壤团聚体总量为人工林地>水田>旱地>撂荒地。且这4种土地利用方式土壤团粒结构分形维数在2.057～2.833之间,表现为团聚体总量越高,其结构的粒径分布的分形维数越高。不同剖面深度表现为:0～5cm团聚体分形维数最高;5～10cm团聚体分形维数最小。分形维数具体表现为林地>水田>旱地>撂荒地,其中分形维数平均为2.832,水田为2.819,旱地为2.658,撂荒地为2.239。土壤颗粒分形维数和有效钾含量呈极显著的正相关;与土壤全氮和速效磷含量呈显著正相关;与全磷、全钾、碱解氮关系不密切。因此,土壤分形维数能客观反映土壤结构性状,是表征土壤结构好坏的一个综合性定量指标。
In order to study the influence of different land use patterns on soil aggregate and to explore the quantitative description of soil quality and structure, the wet sieve method was used to analyze the dry land (corn land), paddy field (Wangtian Tian) and abandoned land The dry land was abandoned for more than 8 years and covered with perennial white grass, and the plantation (Cypress tree, 12-year planting period) was used to determine the soil aggregates content and the fractal characteristics were studied. The results showed that the total amount of soil aggregate was from plantation land> paddy field> dry land> abandoned land. The fractal dimension of soil aggregate was between 2.057 and 2.833, which showed that the higher the total amount of aggregates, the higher the fractal dimension of the particle size distribution of the four land use patterns. The depth of different sections showed the highest fractal dimension of 0 ~ 5cm aggregates and the smallest fractal dimension of 5 ~ 10cm aggregates. The fractal dimension is forest land> paddy field> dry land> wasteland. The average fractal dimension is 2.832, the paddy field is 2.819, the dry land is 2.658 and the wasteland is 2.239. There was a significant positive correlation between fractal dimension of soil particles and available potassium content, a significant positive correlation with soil total nitrogen and available phosphorus, and a weak relationship with total phosphorus, total potassium and available nitrogen. Therefore, the fractal dimension of soil can objectively reflect the soil structure and is a comprehensive quantitative index to characterize the soil structure.