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稳定的土壤团聚结构对种子发芽、根系发育、作物生长以及有机碳保护有着重要的影响。农业管理措施对团聚体胶结剂质量和保存时间影响较大,必然影响土壤团聚体的形成和稳定,不同耕作和育苗方式作为重要的农业管理措施也必将对土壤团聚作用产生影响。选择玉米平作和垄作条件下6种育苗方式的土壤为供试材料,采用标准化平均质量直径和分形理论,探讨了土壤团聚体的稳定性、分形特征及二者之间的关系。结果表明,平作和垄作条件下6种育苗方式对土壤团聚体的稳定性影响不同,平作方式下,秸秆钵直播、包衣直播和垄作方式下,肥团育苗、秸秆钵育苗更有利于大于0.25 mm粒径较大团聚体的形成,对土壤形成稳定的结构具有积极意义;土壤团粒的分形维数与小于0.25 mm粒径含量呈极显著正相关,与0.5～1 mm、1～2 mm粒径含量呈极显著负相关,说明土壤团粒的分形维数越小,土壤团聚体稳定性越强。研究结果说明土壤团聚体的分形维数可以客观地表征土壤结构的稳定性,可以作为表征土壤结构和性质的重要参数,对于深入探讨分形学在土壤综合评价中具有重要意义。
Stable soil agglomeration structure has an important impact on seed germination, root development, crop growth and organic carbon conservation. Agricultural management measures have a great influence on the quality and storage time of agglomerate cement, which will inevitably affect the formation and stability of soil aggregates. As an important agricultural management measure, different farming and nursery methods will also have an impact on soil aggregation. Six kinds of soils were selected as test materials under the conditions of flat planting and ridge cultivation. The stability and fractal characteristics of soil aggregates and the relationship between them were discussed by using standardized average mass diameter and fractal theory. The results showed that under the condition of flat planting and ridge planting, the effect of six kinds of seedling raising methods on the stability of soil aggregates was different. Under the condition of flat cropping, straw stalks direct seeding, direct seeding and ridge planting, seedling raising and straw stalk seedling raising were more beneficial than 0.25 mm particle aggregates formed a positive effect on the formation of stable structure of soil. The fractal dimension of soil aggregates was significantly and positively correlated with the particle size of less than 0.25 mm, but significantly different from that of 0.5 ~ 1 mm and 1 ~ 2 mm particles The results showed that the smaller the fractal dimension of soil aggregates, the stronger the stability of soil aggregates. The results show that the fractal dimension of soil aggregates can objectively characterize the stability of soil structure and can be used as an important parameter to characterize soil structure and properties, which is of great significance for further exploration of the comprehensive evaluation of soil fractal.